Devices and methods for fluid manipulation

Abstract

An Intentional Fluid Manipulation (IFMA) assembly includes: an upstream Intentional Momentum Release Actuator (IMSA) configured to apply a first induced velocity to a localized free-flow during nominal operating requirements, the upstream IMSA generating a flow tube. The IFMA includes a downstream IMSA, wherein a portion or all of the downstream IMSA is located in the downstream portion of the flow tube. The downstream IMSA applies a second induced velocity to the localized free-flow within at least a portion of the flow tube. The second induced velocity at the location of the downstream IMSA has a component in the opposite direction to the first induced velocity at the location of the downstream IMSA.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 933,995, filed November 12, 2019. This application is also a partial successor to U.S. Application No. 16 / 101,391, filed August 10, 2018, which claims the benefits of U.S. Provisional Application No. 62 / 543,371, filed August 10, 2017; U.S. Provisional Application No. 62 / 685,295, filed June 15, 2018; U.S. Provisional Application No. 62 / 703,898, filed July 27, 2018; and U.S. Provisional Application No. 62 / 714,778, filed August 6, 2018. Each of these applications is incorporated herein by reference. Background Technology

[0003] Many fluid interaction devices consume a significant amount of power at low free-flow velocities. For example, a helicopter may require twice the power to hover as it does at nominal level cruise. The propellers of conventional fixed-wing aircraft or the turbofans of commercial jet airliners consume a greater amount of power for a given thrust at lower free-flow velocities (such as those observed during takeoff) than at higher free-flow velocities (such as those observed at nominal level cruise). Similarly, a conventional open-rotor wind turbine is not necessarily capable of extracting a small amount of power from a fluid.

[0004] Attempts to mitigate the inefficiencies in thrust generation or power extraction associated with relatively low free-flow velocities are limited in effectiveness. For example, ducts can be used to increase the local free-flow velocity in propellers, helicopter rotors, or wind turbines. The magnitude of this increase is determined by the geometry of the duct, which is strictly limited by constraints, such as those related to flow separation. These constraints are particularly stringent for smaller free-flow velocities, where ducts are most needed. Due to these constraints, a significant impact on the local free-flow can only be achieved through ducts with large diffusers, which may be associated with excessively large wetting areas and increased weight.

[0005] Objects moving relative to a fluid (such as an aircraft fuselage) typically experience frictional or traction drag. In the prior art, attempts to minimize this traction drag are generally limited to ensuring the wetted surface of the object is as smooth as possible. In some cases, this smoothness can facilitate laminar flow on at least a portion of the wetted surface, which can help reduce viscous traction drag. However, even in the presence of laminar flow, this traction drag is considerable. Summary of the Invention

[0006] According to some embodiments, a fluid manipulation device (such as a helicopter main rotor system) can be configured to reduce power consumption during hovering and increase, for example, hovering duration compared to a conventional helicopter rotor system. These principles also improve the efficiency of thrust generation or power extraction in other types of fluid interaction devices (such as propellers or wind turbines). In some embodiments, the local free-flow velocity of at least a portion of the fluid interaction device that increases thrust generation or power extraction is altered.

[0007] The aforementioned viscous traction resistance is a function of the local free-flow velocity of the fluid relative to the wetted surface of an object. According to some embodiments, a fluid manipulation device can be configured to change the local free-flow velocity of the fluid relative to the wetted surface of an object and reduce the viscous traction resistance. In some embodiments, changing the local free-flow velocity involves reducing at least a portion of the wetted surface of the object.

[0008] Some embodiments include an intentional fluid manipulation device and / or related method, wherein a thrust device assembly having an upstream thrust device can be configured to generate a desired force or thrust relative to free flow in a first direction during nominal operation. The thrust device assembly may further include at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed in at least a portion of the downstream flow tube of the upstream thrust device. The downstream thrust device can be configured to generate thrust at the location of the downstream thrust device in the flow tube of the upstream thrust device, the thrust having at least one vector component in a direction parallel to the induced velocity vector of the upstream thrust device. The thrust of the downstream thrust device may satisfy this directional criterion over at least a portion of the overlapping region between the flow tubes of the upstream and downstream thrust devices. The thrust device assembly may include at least two thrust devices.

[0009] In some embodiments, the flow tube can be bent by an external lifting or thrusting device. In some embodiments, the induced velocity vector of the upstream thrusting device at the location of the downstream thrusting device no longer needs to be aligned with the thrust received by the upstream thrusting device. In some embodiments, it is also possible that the induced velocity vector of the downstream thrusting device at the location of the upstream thrusting device is no longer aligned. In some embodiments, the induced velocity vector of the downstream thrusting device at the location of the downstream thrusting device can be configured to have at least one component in the opposite direction to the induced velocity vector of the upstream thrusting device at that location. In some embodiments, the thrust received by the downstream thrusting device therefore does not necessarily need to have a component in the opposite direction to the thrust of the upstream thrusting device.

[0010] Other embodiments include an intentional fluid manipulation device and / or related method, wherein a thrust device assembly having an upstream thrust device can be configured to apply a first rate of momentum change at least in a desired direction relative to the free-flow velocity vector. The thrust device assembly can include at least one downstream thrust device, wherein the downstream thrust device can be at least partially disposed in at least a portion of the downstream flow tube of the upstream thrust device. The downstream thrust device can be configured to apply a second rate of momentum change to the fluid in the flow tube of the upstream thrust device, wherein, for at least a portion of the overlapping region between the flow tubes of the upstream and downstream thrust devices, the direction of the second rate of momentum change has at least one component in the opposite direction to the effect of the first rate of momentum change on the fluid in the flow tube of the upstream thrust device.

[0011] Other embodiments include an intentional fluid manipulation device and / or related method, wherein a thrust device assembly may include an upstream thrust device configured to deliver a desired amount of induced power to the fluid. The thrust device assembly may include at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed within at least a portion of a downstream flow tube of the upstream thrust device. The downstream thrust device may be configured to extract the desired amount of induced power from the fluid over at least a portion of the overlap between the flow tubes of the upstream and downstream thrust devices.

[0012] Other embodiments include an intentional fluid manipulation device and / or related method, wherein a thrust device assembly includes an upstream thrust device configured to extract a desired amount of induced power from the fluid. The thrust device assembly may include at least one downstream thrust device. The downstream thrust device may be at least partially disposed in at least a portion of the downstream flow tube of the upstream thrust device, and the downstream thrust device may be configured to deliver the desired amount of induced power to the fluid over at least a portion of the overlap between the flow tubes of the upstream and downstream thrust devices.

[0013] Other embodiments include another Intentional Fluid Manipulation Device (IFMA) assembly. The IFMA may include a first thrust device configured to apply a first induced velocity to a localized free-flow during nominal operating requirements, the first thrust device generating a flow tube. A second thrust device may be included. The second thrust device may be located downstream of the flow tube. The second thrust device may be configured to apply a second induced velocity to the localized free-flow. The second induced velocity at the location of the second thrust device may have a component in the opposite direction to the first induced velocity at the location of the second thrust device.

[0014] In some embodiments, the second thrust device may be configured to generate a second thrust at the location of the second thrust device in the flow tube, the second thrust having a vector component that is parallel to and aligned with the direction of the induced velocity vector of the first thrust device.

[0015] In some embodiments, the thrust of the second thrust device can be calculated over at least a portion of the overlapping area between the flow tube of the upstream thrust device and the second flow tube of the second thrust device.

[0016] In some embodiments, nominal operating requirements can be used to provide net thrust, wherein the net thrust in the inertial frame is equal to the first thrust vector of the first thrust device plus the second thrust vector of the second thrust device.

[0017] In some embodiments, the induced power required to generate net thrust can be reduced compared to cases where the effect of the second thrust device on fluid flow is negligible.

[0018] In some embodiments, at least a portion of one of the first or second thrust devices can extract power from a non-zero free-flow.

[0019] In some embodiments, the boundary device can spatially separate the first thrust device from the second thrust device.

[0020] In some embodiments, the first and second thrust devices may be configured to reduce drag loss of the boundary device.

[0021] In some embodiments, the first and second thrust devices may include open rotors or ducted rotors.

[0022] Other embodiments include another intentional fluid manipulation device (IFMA) component. The IFMA may include a boundary device having an outer surface. This boundary device may be configured to move relative to the surrounding fluid. An intentional momentum carrier device (IMCA) may be coupled to the boundary device frame. The IMCA may be coupled to the boundary device in a manner that reduces the velocity gradient near the outer surface of the boundary device frame.

[0023] In some embodiments, the IMCA may be one of a plurality of IMCAs connected to the boundary device frame, and the plurality of IMCAs may be connected to the boundary device in a manner that reduces the velocity gradient near the outer surface of the boundary device frame.

[0024] In some embodiments, a plurality of IMCAs may include a front IMCA located upstream of the boundary device frame, the front IMCA being configured to generate a flow tube extending from the trailing edge of the front IMCA to surround the boundary device frame.

[0025] In some embodiments, multiple IMCAs may include one or more intermediate IMCAs located around a portion of the boundary device frame, wherein the intermediate IMCAs are not following the upstream IMCAs.

[0026] In some embodiments, the intermediate IMCA can be configured to allow the flow tube to be incident on the leading edge stagnation line of the intermediate IMCA.

[0027] In some embodiments, the plurality of IMCAs may include a rear IMCA located downstream of the boundary device frame, the rear IMCA being configured to surround the flow tube from the intermediate IMCA at the leading edge of the rear IMCA.

[0028] In some embodiments, multiple IMCAs may include multiple circular catheters.

[0029] In some embodiments, each of the plurality of catheters may be configured to generate lift having a component in the radially outward direction of a direction axis configured to move relative to the boundary device.

[0030] In some embodiments, multiple IMCAs can be configured to reduce the flow velocity at the outer surface of the boundary device in the event of full slippage.

[0031] In some embodiments, reducing the flow rate can result in lower skin resistance at the outer surface without slippage.

[0032] Some embodiments may include an aircraft. The aircraft may have wings and a fuselage. A downstream thrust device may be attached to the fuselage. The downstream thrust device may be configured to apply a first thrust vector. During nominal level cruise, the aircraft may have a flight direction along the direction of the first thrust vector.

[0033] In some embodiments, the upstream thrust device may be attached to the fuselage. The upstream thrust device may be configured to apply a second thrust vector opposite to the first thrust vector. The second thrust vector may reduce the velocity gradient in the airflow near the fuselage during nominal level cruise.

[0034] In some embodiments, the upstream thrust device may include a duct fan configured to slow the fluid flow before it encounters a fan disc located within the duct fan.

[0035] In some embodiments, the upstream thrust device may be configured to extract energy from the fluid flow.

[0036] In some embodiments, the upstream thrust device may be configured to electrically or mechanically transfer at least a portion of the energy to the downstream thrust device.

[0037] In some embodiments, the magnitude of the first thrust vector may be greater than the magnitude of the second thrust vector.

[0038] Some embodiments may include a fluid manipulation device that may have a boundary device having a surface configured for interaction with a fluid. An intentional fluid manipulation device (IFMA) assembly may be coupled to the boundary device. The IFMA assembly may be configured to reduce the spatial velocity gradient near the surface of the boundary device.

[0039] In some embodiments, the IFMA component may include at least one intentional momentum carrier (IMCA) connected to the boundary device frame.

[0040] In some embodiments, the at least one IMCA may be one of a plurality of IMCAs connected to the boundary device frame.

[0041] In some embodiments, the IFMA component may include an upstream intentional momentum release device (IMSA) configured to apply a first induced velocity to the local free-flow.

[0042] In some embodiments, the IFMA component may include a downstream IMSA configured to apply a second induced velocity to the local free-flow.

[0043] In some embodiments, the thrust vector may be associated with at least one of the upstream IMSAs, and the downstream IMSAs are located in substantially the same direction as the local free-flow.

[0044] In some embodiments, the boundary device may be located between the upstream IMSA and the downstream IMSA.

[0045] In some embodiments, at least one of the upstream IMSA and the downstream IMSA may be configured to extract energy from the fluid flow.

[0046] In some embodiments, energy can be transferred electrically or mechanically between the upstream IMSA and the downstream IMSA.

[0047] In some embodiments, at least one of the upstream IMSA and the downstream IMSA may include a propeller.

[0048] In some embodiments, reducing the velocity of the local free-flow can reduce the resistance of the boundary device.

[0049] In some embodiments, the velocity of the local free flow in the boundary device can be reduced.

[0050] Some embodiments include an Intentional Fluid Manipulation (IFMA) assembly. In some embodiments, the IFMA assembly may include an upstream Intentional Momentum Release (IMSA) configured to apply a first induced velocity to a localized free-flow during nominal operating requirements. In some embodiments, the upstream IMSA may create a flow tube. Some embodiments include a downstream IMSA, wherein at least a portion of the downstream IMSA may be located in a downstream portion of the flow tube. In some embodiments, the downstream IMSA may be configured to apply a second induced velocity to a localized free-flow within at least a portion of the flow tube. In some embodiments, the second induced velocity at the location of the downstream IMSA may have a component in a direction opposite to the direction of the first induced velocity at the location of the downstream IMSA.

[0051] In some embodiments, the intermediate IMSA may be located upstream of the downstream IMSA and / or downstream of the upstream IMSA. In some embodiments, at least a portion of the intermediate IMSA may be located within a portion of the flow tube. In some embodiments, the intermediate IMSA may be configured to apply a third induced velocity to the local free-flow within at least a portion of the flow tube.

[0052] In some embodiments, nominal operating requirements can be used to provide net thrust, wherein the net thrust is equal to the first thrust vector of the upstream IMSA added to the second thrust vector of the downstream IMSA and the third thrust vector of the intermediate IMSA.

[0053] In some embodiments, the induced power associated with the generation of net thrust can be reduced compared to cases where the intermediate IMSA and / or downstream IMSA have a negligible effect on fluid flow, wherein the induced power can be positive or negative.

[0054] In some embodiments, the upstream IMSA or downstream IMSA may include an open rotor, a duct rotor, or a translational or rotating blade or foil.

[0055] In some embodiments, the pitch angle of the rotor blades relative to the rotor hub of the propeller can be changed.

[0056] In some embodiments, the upstream IMSA and / or downstream IMSA are surrounded by pipes.

[0057] In some embodiments, the first induced velocity or the second induced velocity may have a non-zero component that is perpendicular to the local free flow at the upstream IMSA or the downstream IMSA, respectively.

[0058] In some embodiments, the first induced velocity or the second induced velocity may have a non-zero component that is parallel to the local free flow at the upstream IMSA or the downstream IMSA, respectively.

[0059] In some embodiments, the first induced velocity may have a non-zero component in the direction opposite to the direction of the local free flow at the upstream IMSA.

[0060] In some embodiments, the first induced velocity has a non-zero component in the same direction as the local free flow direction at the upstream IMSA.

[0061] In some embodiments, power can be transferred between the upstream IMSA and the downstream IMSA via a power transfer device.

[0062] In some embodiments, power can be transferred mechanically.

[0063] In some embodiments, the power transmission device may include a drive shaft, a gear train, and / or a clutch.

[0064] In some embodiments, power can be transmitted electrically.

[0065] In some embodiments, the downstream IMSA can drive a generator. In some embodiments, electrical energy can be delivered to a motor connected to the upstream IMSA. In some embodiments, the upstream IMSA can drive a generator. In some embodiments, electrical energy can be delivered to a motor connected to the downstream IMSA.

[0066] In some embodiments, power can be transferred from the downstream IMSA to the upstream IMSA.

[0067] In some embodiments, the downstream thrust device may be configured to extract power from the fluid.

[0068] In some embodiments, the power extracted from the fluid by the downstream IMSA may be greater in magnitude than the power transferred to the fluid by the upstream IMSA.

[0069] In some embodiments, the power extracted from the fluid by the downstream IMSA may be less in magnitude than the power delivered to the fluid by the upstream IMSA.

[0070] In some embodiments, the upstream thrust device may be configured to extract power from the fluid.

[0071] In some embodiments, the power extracted from the fluid by the upstream IMSA may be greater in magnitude than the power transferred to the fluid by the downstream IMSA.

[0072] In some embodiments, the power extracted from the fluid by the upstream IMSA may be less in magnitude than the power transferred to the fluid by the downstream IMSA.

[0073] In some embodiments, for a given net thrust, the mass flow rate of the fluid in the flow tube can be altered compared to cases where the effect of the downstream IMSA on fluid flow is negligible. In some embodiments, this alteration can be an increase or a decrease in the mass flow rate.

[0074] In some embodiments, the third induced velocity may have a non-zero component perpendicular to the local free flow at the intermediate IMSA within the flow tube.

[0075] In some embodiments, the third induced velocity may have a non-zero component parallel to the local free flow at the intermediate IMSA within the flow tube.

[0076] In some embodiments, the intermediate IMSA can deliver power to the fluid.

[0077] In some embodiments, the intermediate IMSA can remove electricity from the fluid.

[0078] In some embodiments, the intermediate IMSA may be configured to deliver power to the upstream IMSA and / or downstream IMSA.

[0079] In some embodiments, power can be mechanically transferred between intermediate IMSA and upstream and / or downstream IMSA.

[0080] In some embodiments, power can be electrically transferred between intermediate IMSA and upstream and / or downstream IMSA. In some embodiments, the intermediate IMSA can drive a generator or can be driven by an electric motor. In some embodiments, electrical energy can be transferred to or from an electric motor or generator connected to the upstream and / or downstream IMSA.

[0081] In some embodiments, the intermediate IMSA may include a propeller in an open rotor or duct configuration.

[0082] In some embodiments, the pitch angle of the rotor blades relative to the propeller hub can be varied.

[0083] In some embodiments, the upstream IMSA, intermediate IMSA, and / or downstream IMSA may be surrounded by a conduit.

[0084] In some embodiments, the intermediate IMSA may include a wing or a foil.

[0085] In some embodiments, the intermediate IMSA may include at least a portion of a jet engine. In some embodiments, a group of jet engines may include a turboprop engine, a turbofan jet engine, a turbojet engine, and / or a ramjet engine.

[0086] In some embodiments, the intermediate IMSA may include the core of a jet engine.

[0087] In some embodiments, a portion of the upstream IMSA flow tube may flow over the core of the jet engine. In some embodiments, the remaining portion may form a bypass around the core of the jet engine.

[0088] In some embodiments, the upstream IMSA may include a rotor, and the downstream IMSA may also include a rotor. In some embodiments, the upstream IMSA, the jet engine core, and / or the downstream IMSA may be surrounded by ductwork in the turbofan assembly.

[0089] In some embodiments, the upstream IMSA may include an open rotor and / or the downstream IMSA may include an open rotor.

[0090] In some embodiments, at least a portion of the jet engine's power can be delivered to the upstream IMSA and / or downstream IMSA.

[0091] In some embodiments, the upstream IMSA and downstream IMSA may be configured to increase the mass flow rate of the fluid through the jet engine for a given net thrust during nominal operation, compared to the case where the downstream IMSA has a negligible effect on fluid flow.

[0092] In some embodiments, the third induced velocity at the location of the intermediate IMSA may have a component in the opposite direction to the direction of the first induced velocity at the location of the intermediate IMSA.

[0093] In some embodiments, the third induced velocity at the location of the intermediate IMSA may have a component in the same direction as the first induced velocity at the location of the intermediate IMSA.

[0094] Some embodiments include an IFMA component that may include a volume force generating device configured to generate a volume force per unit mass acting on a fluid and configured to artificially change the mass flow rate of the fluid through a specified cross-sectional area of ​​the fluid flow.

[0095] In some embodiments, the change is an increase or decrease in the mass flow rate.

[0096] In some embodiments, the mass flow rate can be changed by altering the density of the fluid.

[0097] In some embodiments, the mass flow rate can be changed by increasing the fluid density.

[0098] In some embodiments, an increase in fluid density can be facilitated by substantially adiabatic compression of the working material by a volume force generating device.

[0099] In some embodiments, the volume force per unit mass of the fluid may have a component perpendicular to the fluid flow at a specified cross-sectional area.

[0100] In some embodiments, the volumetric force per unit mass of fluid is essentially electric.

[0101] In some embodiments, the volume force generating device may include a collection of electric charges.

[0102] In some embodiments, the collection of charges may be located at the center of the annular flow tube or arranged circumferentially around the annular flow tube.

[0103] In some embodiments, the volume force per unit mass of fluid may be magnetic. In some embodiments, the volume force generating device may include a magnetic field generating device. In some embodiments, the magnetic field generating device may include a permanent magnet or current-carrying wires. In some embodiments, the current-carrying wires may be superconducting or conductive.

[0104] In some embodiments, the specified cross-sectional area may be at least a portion of a jet engine. In some embodiments, the jet engine may include a turboprop engine, a turbofan jet engine, a turbojet engine, or a ramjet engine.

[0105] In some embodiments, the specified cross-sectional area is the cross-sectional area of ​​the core of the jet engine.

[0106] In some embodiments, the specified cross-sectional area is the cross-sectional area of ​​the core of the ramjet engine. Attached Figure Description

[0107] Figures 1 and 2 are cross-sectional views of existing thrust devices.

[0108] Figure 3 This is a cross-sectional view of an intentional fluid manipulation device (“IFMA”) configuration according to some embodiments.

[0109] Figure 4 This is a cross-sectional view of the IFMA configuration according to some embodiments.

[0110] Figure 5 is a cross-sectional view of a prior art fluid manipulation device.

[0111] Figure 6 This is a cross-sectional view of the IFMA configuration according to some embodiments.

[0112] Figure 7 This is a cross-sectional view of the IFMA configuration according to some embodiments.

[0113] Figure 8 and Figure 9 These are cross-sectional views and front views of IFMA configurations according to some embodiments.

[0114] Figure 10 , Figure 11 , Figure 12 and Figure 13 These are perspective views, side views, top views, and rear views configured according to some embodiments of IFMA.

[0115] Figure 14 These are sectional views, perspective views, and oblique views configured according to some embodiments of IFMA.

[0116] Figures 15 to 18 This is a perspective view of various IFMA configurations according to some embodiments.

[0117] Figures 19 to 21 This is a side view of various IFMA configurations according to some embodiments.

[0118] Figures 22 to 26 This is a cross-sectional view of various IFMA configurations according to some embodiments. Detailed Implementation

[0119] As used herein, the term "fluid" encompasses all types of materials that exhibit fluid properties. One such property is the ability of the constituent particles to move relative to each other. For example, it can refer to liquids such as liquids or gases such as air. It should be noted that a fluid can simultaneously contain several different types and kinds of fluids, such as air, which is composed of several gases. Unless otherwise specified, for simplicity, a combination of different fluids is still referred to as a "fluid".

[0120] The term "free-flow" is defined as the theoretical flow relative to a specific point that occurs if an object (such as a component of a device) does not interact with the fluid. Therefore, it can also be called global free-flow. A component of a device can be a vehicle (such as an aircraft or ship) or a different type of fluid manipulation device (such as a wind turbine), or any part of such a component. Free-flow can include the contribution of the motion of a specific point in inertial space, such as the motion of a vehicle in inertial space. It can also include the contribution of the fluid motion in inertial space, such as wind or airflow. Different specific points can experience different free-flows. For example, a device can rotate, causing different points on the device to move at different velocities in inertial space and experience different free-flow velocities in a fluid that is theoretically stationary in inertial space.

[0121] The term "local free-flow" is defined as the theoretical flow relative to a specific device that occurs if only that specific device does not interact with the fluid. Local free-flow includes the contribution of the free-flow itself, as well as contributions due to other devices that interact with the fluid, such as those in the rest of the assembly. For example, the downwash generated by a horizontally fixed wing may affect the magnitude and direction of the local free-flow velocity relative to a horizontal stabilizer mounted downstream of the wing.

[0122] A “fluid manipulation device” or FMA is defined as a device that manipulates the properties of a fluid. For example, for a specific situation or boundary condition, an FMA can change the velocity of a fluid element relative to the magnitude of the free-flow velocity. In another instance, for a specific situation, an FMA can change the direction of the fluid velocity of a fluid element relative to the direction of the free-flow velocity. This effect on fluid flow can be intentional or involuntary. When at least some of the effects on the fluid are intentional, an FMA can be further classified as an “intentional fluid manipulation device” or IFMA. Intentional effects on fluid flow are limited to some IFMAs, such as in the case of an “intentional momentum carrying device” or IMCA as defined below. For other IFMAs, intentional effects on fluid flow can also occur in the far wake, such as in the case of an “intentional momentum release device” or IMSA. These definitions will be clarified in the following paragraphs.

[0123] Due to the intentional nature of momentum release, an IMSA can also be called a "thrust device" or TA, defined as any device configured to apply an intentional rate of change of momentum to a fluid during nominal operation. An example of a TA is a conventional propeller or helicopter main rotor. The wings of fixed-wing aircraft that provide lift during nominal constant-speed cruise can also be considered thrust devices. Many other possible types of TAs are available. For example, the rate of change of momentum can be applied to the fluid by the TA via electromagnetic force. For example, a TA can be a Hall effect thruster or a magnetohydrodynamic (MHD) actuator. Voith-Schneider thrusters, gyroscopes, or similar devices are also examples of TAs.

[0124] In the above definition of a thrust device, the requirement to impose an intentional rate of change of momentum on the fluid can be described in several ways. For example, consider isolating the thrust device from other fluid manipulation devices in the device assembly. For example, consider isolating an airfoil from the rest of a fixed-wing aircraft. Or, consider isolating a helicopter main rotor from the rest of a conventional helicopter. In the theoretical case known as the "isolation case," the thrust device is considered isolated and is defined or characterized as follows: under nominal operating conditions, there is an intentional non-zero induced flow relative to the thrust device in the far wake.

[0125] In some cases, nominal operating conditions may involve the magnitude and direction of a free-flow velocity that is uniform in space and time. In other cases, operating conditions during constant-speed cruise can be described as nominal operating conditions. Under such nominal operating conditions, the far wake is located at an infinite distance from the thrust device. In other words, the thrust device has an intentional, non-negligible effect on the flow field at an infinite distance from the thrust device compared to the free-flow field.

[0126] The term "intentionality," as defined and used herein, refers to the requirement that the rate of change of momentum be useful or deliberate. For example, in the isolation described above, a useful rate of change of momentum can contribute to the average induced velocity of a fluid element in the far wake, where this velocity has a non-zero component in the direction opposite to the expected thrust or lift. For some thrust devices, the average induced velocity of a fluid element in the far wake has a considerable component in the direction opposite to the expected thrust or lift. The far wake-induced flow of a fixed-wing or helicopter main rotor associated with lift or thrust generation is considered intentional. The relevant rate of change of fluid momentum near the thrust device is also considered intentional. The intentional effect of a thrust device on the far wake differs from the unintentional, useless, or reactive effects on the fluid flow field in the far wake, which may be associated with, for example, form drag or pressure drag acting on certain elements of the thrust device. That is, these unintentional effects unnecessarily increase power consumption compared to the theoretical case where these effects are mathematically eliminated, all other things being equal.

[0127] The requirement to impose an intentional rate of change of momentum on a fluid can also be described in another way. For example, a thrust device can also be defined as any device that intentionally releases eddies within the simplified framework of Prandtl's lift line theory. Thus, a thrust device, or TA, or IMSA, can also be described as an "intentional eddy release device" or IVSA. It should be noted that the framework of lift line theory should only be considered as a reference or guide, as it relies on simplifying assumptions such as inviscid and incompressible flow. The intentionally or intentionally released eddies by the thrust device contribute to the lift or thrust acting on the thrust device by imposing a rate of change of momentum on the fluid. When considering the thrust device in the aforementioned isolated case under nominal operating conditions, the intentionally released eddies also exist at an infinite distance from the thrust device, where intentionally induced flow occurs. In other words, there exists a non-zero intentional far-wake induced velocity due to or generated by the thrust device. It should be noted that in some models, such as mathematical models that consider viscous drag or theoretical boundary layer effects that release eddies, the thrust device can also be regarded as releasing eddies unintentionally. Unintentional eddy release refers to any eddy that is not intentionally released, that is, any eddy that does not perform or contribute to a useful function such as generating lift or thrust.

[0128] Intentional momentum-carrying devices (IMCAs) are fluid manipulation devices that, when considered in isolation, do not intentionally release momentum into the far wake. An example of an IMCA is a duct or a conventional tubular or cigar-shaped axisymmetric fuselage. The fuselage alters free-flow by intentionally deflecting the airflow around it, which also increases the magnitude of the flow velocity near the fuselage in isolation, where the fuselage is considered isolated from any other fluid manipulation device (such as a wing) under nominal operating conditions (such as constant speed cruise). The intentional deflection of the flow described above is confined to the vicinity of the fuselage. Therefore, fluid elements near the fuselage experience an intentional local rate of momentum change. Ideally, this has no effect on fluid flow at an infinite distance from the fuselage. In other words, the fuselage has no intentional far wake effect on fluid flow. However, there may be inadvertent rates of momentum change in the fluid near the fuselage, which, compared to free-flow, may also be associated with inadvertent momentum changes in fluid elements at an infinite distance from the fuselage in isolation. For example, such unintentional changes in fluid flow in the far wake can be caused by the shape drag effect.

[0129] Similarly, a conduit alters free-flow by intentionally changing the velocity magnitude near the conduit. For example, a conduit can be configured to reduce the velocity magnitude of the fluid element at the center of a circular conduit relative to free-flow under isolated conditions of nominal operating conditions. In this case, nominal operating conditions can refer to a constant and uniform free-flow velocity parallel to the conduit's central axis of symmetry. This intentional change is limited to the vicinity of the conduit and converges to a negligible value at an infinite distance from the conduit center. Therefore, the conduit has no intentional far-wake effect on the fluid flow; that is, there is no intentionally induced velocity in the far-wake of the fluid element due to the interaction between the conduit and the fluid. As mentioned earlier, there may be unintentional changes in the fluid flow in the far-wake due to traction drag or transient effects, as well as associated unintentional rates of momentum change of the fluid near the conduit.

[0130] IMCA can also be described within a simplified framework of lift line theory. IMCA can be viewed as having closed or bounded vorticity. Therefore, IMCA can also be considered as an "intentional vortex-carrying device" or IVCA. For example, the intentional effect of an axially symmetric circular duct on the fluid can be modeled as a circular vortex ring, or a two- or three-dimensional continuous vortex distribution, or a gradually decreasing discrete vortex ring. Note that under nominal operating conditions, no intentional vorticity is released into the fluid, where the magnitude of the vorticity is constant in time and uniform along the circumference of the vortex ring. Similarly, the intentional effect of the fuselage on fluid flow can be modeled as a three-dimensional continuous vortex distribution contained within the fuselage or located on the fuselage surface (i.e., the interface between the fuselage and the fluid).

[0131] The “induced power” of an IMSA is the rate of change of fluid energy associated with the intentional rate of change of the fluid’s momentum. Any other power consumption is included in the “zero-lift power” or “profile power.” It should be noted that in this context, the term “lift” also includes thrust. It should be noted that IMCA does not consume any induced power. Any power loss associated with pure IMCA is considered a profile power loss. An IMSA can consume induced power, in which case intentional work is done on the fluid through the fluid manipulation device. For example, the propeller of an aircraft or ship, or the fixed wing of a conventional fixed-wing aircraft, results in or is associated with induced power consumption. An IMSA can also recover induced power, in which case intentional work is done on the fluid manipulation device through the fluid. For example, the power generated by a wind turbine can be considered induced power.

[0132] In applying a rate of change of momentum to a fluid, a fluid manipulation device can alter the flow velocity relative to the local free-flow velocity. This velocity change is called "downwash" or "induced velocity." It should be noted that, for example, the induced velocity can be directed downstream or upstream, or perpendicular to the airflow. The induced velocity can be generated by an IMSA or an IMCA. In the latter case, the induced velocity is localized, i.e., confined to the vicinity of the IMCA. In these terms, an IMSA can also be characterized as a device that contributes an intentional induced velocity to the far wake in isolated conditions. It should be noted that when two IMSAs are considered simultaneously, the induced velocity contribution of one IMSA can be canceled out by the other.

[0133] Several apparatuses and methods used in the prior art will be discussed in the following paragraphs and in the context of Figures 1 and 2.

[0134] Figure 1 is a cross-sectional view of the prior art TA. It illustrates propeller 1, with the thrust of propeller 1 pointing towards the top of the figure, as shown by thrust vector 39. Under the operating conditions shown, there is a non-zero free flow from the top to the bottom of the figure, as indicated by arrow 40.

[0135] The dashed line schematically represents the approximate boundary 2 between the free-flow and the flow passing through the rotor disk. The line on the boundary can be described as a streamline, and the volume enclosed by the boundary can be described as a flow tube. It should be noted that the boundary shown in the figures is only an example of a specific operating condition. For other operating conditions or modes of operation of the depicted TA, such as hovering or extracting energy from free-flow (such as a phoenix or water flow), the shape of the boundary can be quite different. In the free-flow far in front of the propeller, the flow is approximately equivalent to free-flow.

[0136] This state of the fluid is represented by station 3 in Figure 1. The fluid characteristics at the propeller are encapsulated by station 4. The flow in the far wake, or the free flow far downstream of the propeller, is represented by station 5. Because the propeller accelerates the flow, the area of ​​the flow tube decreases from station 3 to station 4 and from station 4 to station 5.

[0137] At station 5, the flow exhibits a greater velocity than free-flowing flows (such as those observed at station 3), where, within the framework of conventional simple momentum theory, it can be assumed that the flow pressure inside the flow tube has returned to the free-flow pressure. The greater velocity at station 5 indicates an increase in fluid momentum due to the propeller accelerating the flow and subjecting it to an equal and opposite force or thrust. The higher the velocity, the greater the kinetic energy in the fluid; in the aforementioned framework, kinetic energy represents the power required to provide the thrust.

[0138] It should be noted that the simple momentum theory is used only as a framework to describe the basic principles of lift using TA, and the assumptions generally included in this theory are not intended to apply to the embodiments or limit the scope. For example, the distribution of the airflow downwash generally does not need to be constant across the cross-section of the flow tube. It should be noted that the flow tube radius drawn at each station is approximate and is intended only to indicate the general shape of the flow tube.

[0139] The cross-sectional view of the propeller shows the first propeller blade 6 and the second propeller blade 7. The trailing edge 9 of the first propeller blade 6 and the leading edge 10 of the second propeller blade 7 are also visible. A similar configuration is shown in all the figures containing the propeller.

[0140] Figure 2 is a cross-sectional view of another prior art TA. A ducted propeller is illustrated, with the thrust of propeller 11 pointing towards the top of the figure, as shown by thrust vector 41. Under the operating conditions shown, there is a non-zero free flow from the top to the bottom of the figure, as indicated by arrow 42. Additional thrust is generated by duct 16, which has a leading edge 17, a trailing edge 18, and a cross-section 19. Similar to Figure 1, there is a flow tube boundary 12 with a far upstream position 13, a position 14 at the rotor, and a far wake position 15. Duct 16 circumferentially surrounds propeller 11.

[0141] According to some embodiments, an apparatus and method are provided that can modify flow more effectively than methods employed in the prior art. The modification may involve, but is not limited to, the flow velocity at a specific location in the flow, and may be applied, but is not limited to, generating thrust.

[0142] The method includes: providing a thrust device assembly having an upstream thrust device configured to generate a desired force or thrust relative to free-flow in a first direction during nominal operation; and further providing a thrust device assembly having at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed in at least a portion of a downstream flow tube of the upstream thrust device; and wherein the downstream thrust device is configured to generate thrust at the location of the downstream thrust device in the flow tube of the upstream thrust device, the thrust having at least one vector component in a direction parallel to the induced velocity vector of the upstream thrust device, wherein the thrust of the downstream thrust device satisfies the directional criterion in at least a portion of the overlapping region between the flow tubes of the upstream and downstream thrust devices. The thrust device assembly may include at least two thrust devices.

[0143] It should be noted that the flow tube can be bent by an external lifting device or thrust device. In some cases, the induced velocity vector of the upstream thrust device at the location of the downstream thrust device no longer needs to be aligned with the thrust received by the upstream thrust device. In some cases, it may also be unnecessary for it to be aligned with the induced velocity vector of the upstream thrust device at its location. The induced velocity vector of the downstream thrust device at its location is configured to have at least one component in the direction opposite to the induced velocity vector of the upstream thrust device at that location. Therefore, the thrust received by the downstream thrust device does not necessarily need to have a component in the direction opposite to the thrust of the upstream thrust device.

[0144] Alternatively, the method includes: providing a thrust device assembly having an upstream thrust device configured to apply a first momentum change rate in at least a predetermined direction relative to the free flow velocity vector; and further providing a thrust device assembly having at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed in at least a portion of a downstream flow tube of the upstream thrust device; and wherein the downstream thrust device is configured to apply a second momentum change rate to fluid in the flow tube of the upstream thrust device, wherein, for at least a portion of the overlapping region between the flow tubes of the upstream and downstream thrust devices, the direction of the second momentum change rate has at least one component in the opposite direction to the effect of the first momentum change rate on the fluid in the flow tube of the upstream thrust device.

[0145] Alternatively, the method includes: providing a thrust device assembly having an upstream thrust device configured to deliver a desired amount of induced power to a fluid, and further providing a thrust device assembly having at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed in at least a portion of a downstream flow tube of the upstream thrust device, and wherein the downstream thrust device is configured to extract the desired amount of induced power from the fluid in at least a portion of the overlapping region between the flow tubes of the upstream and downstream thrust devices.

[0146] Alternatively, the method includes: providing a thrust device assembly having an upstream thrust device configured to extract a desired amount of induced power from a fluid, and further providing a thrust device assembly having at least one downstream thrust device, wherein the downstream thrust device is at least partially disposed in at least a portion of a downstream flow tube of the upstream thrust device, and wherein the downstream thrust device is configured to deliver the desired amount of induced power to the fluid over at least a portion of the overlap region between the flow tubes of the upstream and downstream thrust devices.

[0147] One advantage of such thrust device components is the alteration of flow velocity at specific points within the flow tube. For example, at a station between upstream and downstream thrust devices, the flow velocity can be artificially increased. Ideally, any work done by the upstream thrust device can be recovered by the downstream thrust device, minimizing energy loss in the process. Furthermore, any undesirable momentum changes exerted on the fluid by the upstream thrust device can be eliminated by the downstream thrust device. In other words, any undesirable thrust experienced by the upstream thrust device can be counteracted by the downstream thrust device. Therefore, some embodiments provide a method for altering flow that can be more efficient than methods employed in the prior art.

[0148] There are many possible embodiments of apparatus employing the above method. Figure 3 One embodiment is shown. The figure illustrates a thrust assembly comprising an upstream thrust unit 20 and a downstream thrust unit 21. The upstream thrust unit 20 can be classified as a propeller, and the downstream thrust unit 21 can also be described as a propeller in this case. In other embodiments, the type of thrust unit 20 or 21 may differ from the open rotor type shown. For example, the thrust unit may comprise several open rotors, or it may comprise at least one ducted fan or a pair of counter-rotating coaxial propellers. Similar to Figure 1, there is a flow tube boundary 22 having a far upstream position 23, a position 24 at the upstream thrust unit 20, a position 25 between the upstream thrust unit 20 and the downstream thrust unit 21, a position 26 at the downstream thrust unit 21, and a far wake position 27. In this case, the downstream thrust unit 21 is disposed within the flow tube 22 of the upstream thrust unit 20.

[0149] In this example, the thrust assembly needs to provide a net thrust pointing vertically upwards towards the top of the figure, as shown by the thrust vector. There is a free flow from the top to the bottom of the figure, as indicated by arrow 45. The purpose of this embodiment is to reduce the induced power of the thrust assembly for a given amount of thrust, compared to a baseline configuration. In this case, the baseline configuration is a single open rotor, such as the open rotor example shown in Figure 1, where the net thrust and actuator disk area are the same at stations 4 and 24.

[0150] According to some embodiments, this is achieved through the following Figure 3 This is achieved using the IFMA configuration shown. The upstream thrust unit 20 is configured to provide thrust parallel to and greater than the required net thrust of the thrust unit assembly, where the net thrust is the sum of the thrust of the upstream thrust unit 20 and the thrust of the downstream thrust unit 21. The net thrust on the thrust unit assembly needs to equal the required thrust. Therefore, the thrust on the downstream thrust unit 21 is equal to the difference between the net thrust and the thrust of the upstream thrust unit 20. In this case, this results in the thrust on the downstream thrust unit 21 pointing vertically downwards towards the bottom of the figure, as shown by the thrust vector, in the opposite direction to the thrust on the upstream thrust unit 20. In other words, the downstream thrust unit 21 is configured to extract any momentum applied to the fluid by the upstream thrust unit that would violate, and in this case exceed, the required net thrust constraint on the thrust unit assembly. The downstream thrust unit 21 is also configured to extract power from the fluid. To improve induced power consumption compared to the baseline, sufficient portion or all of the extracted induced energy needs to be reversibly recovered or directly transferred to the upstream thrust unit 20.

[0151] Energy can be reversibly recovered by either storing it reversibly within the thrust assembly or transferring it reversibly to another device that interacts with the thrust assembly. For example, a downstream thrust unit can drive a generator G, which may include an electric motor configured to convert a portion of mechanical energy into electrical energy. A portion of the electrical energy can be reversibly stored in a battery, capacitor, or other energy storage device. The battery can be located within the thrust assembly or on an external device attached to the thrust assembly (such as the rest of the vehicle). Energy can also be mechanically extracted and stored in the form of a flywheel.

[0152] Energy can be directly transferred to the upstream thrust device 20 in several ways. For example, if energy is extracted from the downstream thrust device 21 via a generator G, electrical energy can be transferred via electrical conductors or wires to the electric motor M driving the upstream thrust device 20. Alternatively, the power extracted by the downstream thrust device can be mechanically transferred in the form of a drive shaft that rigidly connects the upstream thrust device 20 and the downstream thrust device 21. In some embodiments, the mechanical energy transfer device does not need to form a rigid connection, but instead includes adjustable linkages, gears, and other mechanisms such as clutches.

[0153] There are many other known methods in the art for recovering and storing mechanical energy from downstream thrust device 21 or for transferring mechanical energy to upstream thrust device 20.

[0154] The above embodiment results in an induced power lower than the baseline induced power. For a given maximum actuator disk area and a given net thrust at stations 4 and 24, the induced power decreases as the thrust of the upstream thrust device 20 increases. It should be noted that the thrust of the upstream thrust device 20 needs to be greater than the required net thrust in order to achieve a reduction in induced power compared to the baseline in this example.

[0155] Some embodiments provide improvements to the ducted thrust device shown in Figure 2. This duct offers several advantages, such as reduced propeller tip losses, allowing the duct to operate with lower induced power at the same thrust as an open rotor. However, the duct also has several disadvantages. It can increase the weight of the TA, as well as the wetting area and associated drag. The effectiveness of the duct is also limited by the risk of flow separation in the diffuser. Furthermore, due to complexity and weight, altering the shape of the duct to achieve efficiency gains at different flow rates is generally impractical.

[0156] Some embodiments are less affected by some of these disadvantages. For some ductless embodiments, the thrust unit can benefit from the duct without equivalent losses in weight and wetting area. To avoid flow separation, a duct would require a large diffuser, which may be impractical due to weight and size constraints. Ductless embodiments are less sensitive to stall constraints, which will allow some embodiments to achieve better performance than ducted rotors. The thrust unit can also be reconfigured with less complexity than a ducted rotor. For example, an open rotor type thrust unit can be reconfigured by changing the overall pitch of the propeller blades, and the rotational speed can be easily controlled. This allows the thrust unit to operate more efficiently with less complexity under different operating conditions, such as hovering or level cruise.

[0157] It should be noted that, Figure 3In this configuration, the upstream thrust device 20 provides the required thrust for a particular thrust device assembly and additional thrust offset by the downstream thrust device 21. In some embodiments, it may be desirable to physically separate the thrust devices that offset each other's net thrust contribution to the thrust device assembly from the rest of the thrust device assembly.

[0158] Figure 4 This situation is illustrated. The figure shows an auxiliary thrust assembly comprising an upstream thruster 28 and a downstream thruster 30, where the upstream thruster 28 can be classified as a propeller, and the downstream thruster 30 can also be described as a propeller in this case. The figure also shows an intermediate thruster 29, which is also an open rotor type. There is a free flow pointing vertically downwards from the top of the figure to the bottom, as indicated by arrow 49. Similar to Figure 1, there is a flow tube boundary 31 with a far upstream position 32, a position 33 at the upstream thruster 28, a position 34 between the upstream thruster 28 and the intermediate thruster 29, a position 35 at the intermediate thruster 29, a position 36 between the intermediate thruster 29 and the downstream thruster 30, a position 37 at the downstream thruster 30, and a far wake position 38. In this case, the intermediate thrust device 29 and the downstream thrust device 30 are disposed in the flow tube 31 of the upstream thrust device 28.

[0159] In this example, the intermediate thrust unit 29 provides thrust equal to the required net thrust of the total thrust assembly, as shown by thrust vector 47, where the thrust assembly includes the upstream thrust unit 28, the intermediate thrust unit 29, and the downstream thrust unit 30. Therefore, the auxiliary thrust assembly does not need to provide net thrust. Figure 3 As shown, the purpose of the embodiment in this example is to reduce the induced power of the total thrust device assembly at a given amount of thrust, compared to the baseline configuration. In this case, the baseline configuration is also a single open rotor, such as the open rotor example shown in Figure 1, where the net thrust and actuator disk area are the same at stations 4 and 33.

[0160] According to some embodiments, this is achieved through the following Figure 4This is achieved in the illustrated embodiment. The upstream thrust device 28 is configured to provide thrust that is parallel to and greater than the required net thrust of the total thrust device assembly, where the net thrust is the thrust of the upstream thrust device 28 plus the thrust of the intermediate thrust device 29 plus the thrust of the downstream thrust device 30. Therefore, the thrust of the upstream thrust device 28 points towards the top of the page, as shown by thrust vector 46. In this case, the thrust on the downstream thrust device 30 is equal to and opposite to the thrust of the upstream device 28, as shown by thrust vector 48. In other words, the downstream thrust device 30 is configured to extract any momentum applied to the fluid by the upstream thrust device that would violate, and in this case exceed, the required net thrust constraint on the total thrust device assembly. The downstream thrust device 30 is also configured to... Figure 3 The downstream thrust device 21 in the process describes the way power is extracted from the fluid.

[0161] It should be noted that the upstream and downstream thrust devices do not need to operate individually with minimum induced power, as long as the total induced power is minimized, if that is the objective. For example, if the objective is to maintain a constant airflow downwash across the cross-section of the far-flow tube at station 38, the airflow downwash from the upstream thrust device 28 or the intermediate thrust device 29 does not need to be uniform, as long as any non-uniformity is eliminated by the downstream thrust device.

[0162] It should be noted that the principles applicable to coaxial propellers also apply to some embodiments. For example, the actuator disk area at station 35 of the intermediate thrust unit 29 can be as large as the actuator disk area of ​​the upstream thrust unit 28 at station 33. Therefore, a portion of the intermediate thrust unit interacts with the free flow. This area can be used to further apply a rate of change of momentum to the fluid in the direction of the desired thrust of the total thrust unit assembly. This allows the thrust unit assembly to further reduce the induced power compared to the baseline. Similarly, the actuator disk area of ​​the downstream thrust unit can be increased, such as... Figure 4 30 or Figure 3 21. The concept of interaction with bypass fluid flow is well known in the art. Furthermore, as is known in the prior art, the direction of rotation of the propeller in the flow tube can be selected to minimize vortices in the far wake.

[0163] Other embodiments will be described in the following paragraphs.

[0164] For generality, it is beneficial to consider embodiments individually. In one embodiment, the purpose of the device is to increase the local velocity relative to free flow at a specific point in the flow. This can be achieved by a thrust device assembly having an upstream thrust device configured to apply a rate of change of momentum downstream, thereby generating a downstream induced velocity vector. The upstream thrust device is located upstream of the specific point in the flow and is thrust in the upstream direction, doing work on the fluid, resulting in induced power consumption. The thrust device assembly may further include a downstream thrust device configured to apply a rate of change of momentum upstream, thereby generating an upstream induced velocity vector. The downstream device is located in the flow tube of the upstream thrust device. The downstream thrust device is located downstream of the specific point in the flow and is thrust in the downstream direction, recovering power from the fluid. Ideally, all induced power applied to the fluid by the upstream device is recovered by the downstream device, such that no net induced power is lost to the fluid. In an idealized case requiring zero net thrust of the thrust device assembly, the thrusts on the upstream and downstream thrust devices further cancel each other out. Provided the upstream and downstream thrust assembly are positioned sufficiently far apart to allow for flow acceleration, a specific point between the upstream and downstream thrust assemblies can experience a desired increase in local velocity. This is due to the induced flow or downwash from the upstream thrust assembly and the downwash from the downstream thrust assembly. This downwash can then be further recovered downstream of the specific point by the downstream thrust assembly, so that, ideally, no downwash exists in the far wake of the flow tube.

[0165] In another embodiment, the purpose of the device is to reduce the local velocity at a specific point in the flow. According to some embodiments, this can be achieved by reversing the actions of the upstream and downstream thrust devices, compared to the examples described above. Thus, the upstream thrust device can be configured to apply a rate of change of momentum upstream, thereby generating an upstream induced velocity vector. Similarly, the downstream thrust device can be configured to apply a rate of change of momentum downstream, thereby generating a downstream induced velocity vector. Ideally, all induced power recovered by the upstream device is consumed by the downstream device, so that the thrust devices do not extract net induced power from the fluid.

[0166] It should be noted that the upstream thrust device only needs to meet local velocity requirements at specific points. Compared to free flow, different points in the flow tube containing the actuator disk area of ​​the upstream thrust device may require different increases or decreases in local velocity. Local velocity requirements can be viewed as requirements for the airflow downwash of the thrust device components at specific points or point sets within the flow tube, or near the flow tube. These requirements can be met by varying the thrust distribution over the actuator disk areas of the upstream and downstream thrust devices. Considering these flow constraints at specific points, additional objectives may exist, such as minimizing induced power, which can be translated into additional requirements for zero or uniform downwash in the far wake. This objective could also be minimizing the total power consumed under these operating conditions.

[0167] Consider the operating conditions of the thrust assembly, aiming to maximize the power extracted from the fluid for a given maximum actuator disk area and freeflow velocity, assuming that structural constraints are always satisfied. A baseline configuration consisting of open rotors (such as wind turbines) can be considered. According to some embodiments, the thrust assembly may include an upstream thrust unit and a downstream thrust unit. In this example, the downstream thrust unit is disposed in the slipstream of the upstream thrust unit. There is a non-zero freeflow. The upstream thrust unit is configured to do work on the freeflow by applying a rate of change of momentum to the flow in the downstream direction. Through interaction with the fluid, the upstream thrust unit is thus subjected to an upstream-directed force. The downstream thrust unit is configured to extract power from the flow in the flow tube of the upstream thrust unit. In other words, the fluid does work on the downstream thrust unit and is subjected to an upstream-directed rate of change of momentum, causing the downstream thrust unit to be subjected to a downstream-directed force. Therefore, performance improvements can be achieved compared to the baseline open rotor configuration. For example, a wind turbine may include two open rotors, one located upstream of the mast and the other downstream of the mast. The rotors can operate as described above. The power consumed by the upstream rotor can be supplied by an external power source or the downstream rotor. For example, in Figure 3 As mentioned in the description, power can be mechanically transferred between the upstream and downstream thrust units, for example, via a direct connection to the shaft or via an adjustable transmission including gear trains and clutches. Power can also be transferred electrically, in which the downstream rotor drives a generator, and the generator's electrical energy is transferred to the electric motor driving the upstream rotor. It should be noted that other configurations are also possible, and the principle also applies to hydraulic turbines or other thrust units or operating conditions.

[0168] In some embodiments or operating conditions, it may be desirable to reduce, rather than increase, the local flow velocity at the actuator disk of the downstream rotor. For example, in the case of a wind turbine, the free-flow velocity may exceed the permissible peak free-flow velocity of the downstream rotor under certain operating conditions. It should be noted that due to the different dimensions and nominal operating loads of the upstream and downstream rotors, the peak free-flow velocity of the upstream rotor, determined by structural constraints, may be greater than that of the downstream rotor. They may also differ in design. In this case, the thrust on the upstream rotor can be reversed to extract power from the flow and reduce the velocity at the downstream rotor to a nominal level. This prevents the thrust on the downstream rotor from exceeding design limits. Therefore, the upstream thrust device can be used to modify the flow field, thereby optimizing the performance of the entire thrust device assembly. It should be noted that other methods known in the art are also applicable to such situations. In the case of a single open rotor, operating conditions such as rotational speed and propeller pitch can be adjusted. However, the effectiveness of these methods is limited by the range of free-flow velocities, and some embodiments can extend these limitations. The principles described in the context also apply to other operating conditions and situations.

[0169] In the following paragraphs and in the context of Figure 5, some of the devices and methods used in the prior art will be discussed.

[0170] "Boundary device" includes any incremental surface or volume of a fluid manipulation device that directly applies force or torque to a fluid element, or vice versa. Examples of boundary devices are the wetted surfaces of an aircraft fuselage, the wetted surfaces of a ship's hull, the skin of an aircraft wing, the surface of a flat plate, or the outer surface of a car.

[0171] Figure 5 shows a cross-sectional view of a boundary device 61 moving relative to the surrounding fluid. The boundary device 61 has a leading edge point 64 and a trailing edge point 65. The leading and trailing edge points can also be edges, such as the leading or trailing edge of an airfoil. In this particular embodiment, for simplicity, the boundary device is a rigid body that can be described as a thin shell, having a closed outer surface 62 and an inner surface 63. In this embodiment, the boundary device 61 has a shape of revolution, i.e., it is axisymmetric about an axis passing through the leading edge point 64 and the trailing edge point 65.

[0172] The "Boundary Device Frame" or "BAF" can be defined as follows: The origin is located at the geometric centroid of the volume enclosed by the outer surface 62 of the boundary device 61. The x-axis coincides with the line connecting the leading edge point 64 and the trailing edge point 65, and points towards the leading edge point 64. Unless otherwise specified, the z-axis points perpendicularly to the page of the accompanying drawing.

[0173] Three velocity distribution diagrams 67-69 are shown. Each arrow in the velocity distribution diagram indicates the velocity vector of the incremental fluid element relative to the boundary device, with the incremental fluid element located at the base of the arrow. The line connecting the tips of the arrows in velocity distribution diagram 67 describes the continuous velocity distribution.

[0174] Boundary device 61 moves relative to the surrounding fluid. The free-flow velocity is spatially uniform and temporally constant. In Figure 5, the free-flow fluid relative to boundary device 61 is parallel to the x-axis of the BAF and guided in the opposite direction to the x-axis of the BAF, i.e., from the top to the bottom of the figure. Upstream of the distal end of boundary device 61, the velocity of the incremental fluid element is approximately equal to the free-flow velocity. Therefore, the velocity distribution map 67 is uniform, with both magnitude and direction equal to the free-flow velocity.

[0175] Velocity distribution diagram 68 illustrates the velocity distribution near the boundary device 61. In this embodiment, a no-slip condition exists on the surface of the boundary device 61. In other embodiments, non-zero slip velocity may exist along the outer surface 62. Due to viscous effects, the velocity gradient generated in the y-axis direction of the BAF causes shear stress acting on the boundary device 61, which in turn causes viscous traction drag. The viscous traction drag is parallel to the x-axis of the BAF and points in the negative x-direction.

[0176] Streamline 66 describes the approximate thickness of the boundary layer associated with boundary device 61. Since boundary device 61 is cylindrically symmetrical, streamline 66 can also be referred to as flow tube 66.

[0177] Velocity distribution diagram 69 illustrates the velocity distribution in the far wake of boundary device 61. The decreasing velocity magnitude within flow tube 66 in velocity distribution diagram 69 indicates the momentum deficit in the far wake caused by the viscous drag acting on boundary device 61.

[0178] According to some embodiments, the flow field around the boundary device is altered by a fluid flow manipulation device in such a way that, for at least one operating condition, the viscous resistance on the combined device is lower than that of the baseline boundary device.

[0179] The baseline boundary device does not need to have the same shape as the boundary device in the combined device. The baseline boundary device is a conventional device used in the prior art, such as the boundary device 61 shown in Figure 5. For example, the baseline boundary device can have the shape of a conventional tubular aircraft fuselage.

[0180] Slip velocity is the velocity of a fluid at and relative to the surface of a boundary device. In viscous fluids, the slip velocity is typically smaller in magnitude than the slip velocity calculated for the theoretical case of an inviscid fluid. The difference between these two velocities is called the "velocity deficit." Due to viscous effects, the velocity deficit at the boundary device surface propagates through the fluid in a direction perpendicular to the local free-flow velocity. As a result, a non-negligible fluid volume is affected by the velocity deficit. The fluid flow region affected by this velocity deficit is called the boundary layer. The thickness of this region is called the boundary layer thickness. All else being equal, the boundary layer thickness can be defined as the region where the velocity deficit is greater than 1% of the magnitude of the velocity calculated for the theoretical case of an inviscid fluid. The velocity deficit translates into a momentum deficit, which causes viscous shear stress and viscous drag acting on the boundary device.

[0181] According to some embodiments, compared to a case where the influence of the fluid flow manipulation device on the fluid flow is mathematically eliminated, the local free-flow velocity is reduced for at least a portion of the wetted area of ​​the combined device. The fluid flow manipulation device is configured such that the increase in power consumption of the combined device due to the additional wetted area of ​​the fluid flow manipulation device compared to the baseline boundary device is less than the reduction in power consumption of the boundary device due to the traction resistance acting on the boundary device compared to the baseline boundary device. A portion of the reduction in power consumption of the boundary device can be caused by the reduction in the local free-flow velocity of the boundary device. Alternatively or simultaneously, the fluid manipulation device can be configured to favor laminar flow rather than turbulent flow in at least a portion of the boundary layer of the boundary device. Another portion of the reduction in power consumption can be caused by a change in the shape of the boundary device compared to the baseline boundary device. The fluid flow manipulation device can manipulate the flow such that the wetted area of ​​the boundary device can be reduced without increasing pressure drag due to the separation of a portion of the flow. For a given volume to be surrounded by the boundary device, the shape of the boundary device with the smallest wetted area is a sphere. However, a sphere causes significant pressure drag due to stall flow downstream of it. Even without stall, a sphere exhibits significant viscous drag due to its large mean square local free-flow velocity over its wetted area and the boundary layer effect. Besides reasons such as ease of manufacture, most fuselages have an elongated shape resembling a tube or teardrop for these reasons. Fluid manipulation devices can alter the flow, reducing the wetted area of ​​the boundary device and simultaneously decreasing the mean square local free-flow velocity compared to the baseline boundary device.

[0182] Flow field alterations can take several forms, and each form of alteration can be performed through several different embodiments of the fluid manipulation device.

[0183] Figure 7An IFMA configuration is depicted, comprising a boundary device 95 that moves relative to the surrounding fluid. The boundary device 95 has a leading edge point 98 and a trailing edge point 99. The leading and trailing edge points can also be edges, such as the leading or trailing edge of a wing or airfoil. In the case of a wing, the leading and trailing edges can be considered as a leading and trailing stagnation line under specific flow conditions. In this embodiment, the boundary device is a rigid body that can be described as a thin shell, having a closed outer surface 96 and an inner surface 97. In this embodiment, the boundary device 95 has a rotational shape, i.e., it is axisymmetric about an axis passing through the leading edge point 98 and the trailing edge point 99.

[0184] Boundary device 95 can be the hull of a ship or the fuselage of an aircraft. In other embodiments, boundary device 95 can have different geometries. For example, the shape of the boundary device can be similar to that of boundary device 61 shown in FIG. 5. Suitable geometries can be found for any given application. Boundary devices can be manufactured using a variety of existing methods and materials.

[0185] The "Boundary Device Frame" or "BAF" can be defined as follows. The origin is located at the geometric centroid of the volume enclosed by the outer surface 96 of the boundary device 95. The x-axis coincides with the line connecting the leading edge point 98 and the trailing edge point 99, and points towards the leading edge point 98. Unless otherwise specified, the z-axis points perpendicularly to the page of the accompanying drawing.

[0186] Three velocity distribution diagrams 101-103 are shown. Each arrow in the velocity distribution diagram indicates the velocity vector of the incremental fluid element relative to the boundary device, where the incremental fluid element is located at the base of the arrow at the time point in time at which the velocity is measured relative to the boundary device. The line connecting the tips of the arrows in the velocity distribution diagram describes a continuous velocity distribution.

[0187] The boundary device 95 moves relative to the surrounding fluid. In the simplified case illustrated, the free flow velocity is spatially uniform and temporally constant. Figure 7 In the diagram, the free-flowing fluid relative to boundary device 95 is parallel to the x-axis of the BAF and guided in the opposite direction to the x-axis of the BAF, i.e., from the top to the bottom of the diagram. Upstream of the far end of boundary device 95, the velocity of the incremental fluid element is approximately equal to the free-flowing velocity. Therefore, the velocities in velocity distribution diagram 101 are spatially uniform and temporally constant, with magnitude and direction equal to the free-flowing velocity relative to the boundary device.

[0188] Velocity distribution diagram 102 illustrates the velocity distribution near the boundary device 95. In this embodiment, a no-slip condition exists on the outer surface 96 of the boundary device 95. In other embodiments, there may be non-zero slip velocity along the outer surface 96.

[0189] Streamline 100 describes the boundary of the flow tube, which has a circular cross-section when viewed along the x-direction. Figure 7 The dashed line in the diagram schematically represents the approximate boundary 100 between the free flow and the flow passing through the rotor disk of the upstream IMSA 104. The lines on the boundary can be described as streamlines, and the volume enclosed by the boundary can be described as a flow tube. It should be noted that... Figure 7 The boundary shown is only an example of a specific operating condition. For other operating conditions or modes of operation of the IMSA depicted, the shape of the boundary can be quite different.

[0190] Velocity distribution diagram 103 depicts the velocity distribution in the far wake of boundary device 95. In a simplified ideal case, velocity distribution diagram 103 is essentially equal to velocity distribution diagram 101, as shown below. Figure 7 As shown. In other embodiments, this is not necessarily the case.

[0191] According to some embodiments, the boundary device (such as boundary device 95) is provided with intentional fluid manipulation means. Figure 7 In the illustrated IFMA configuration, the intentional fluid manipulation device can be described as an IMSA assembly comprising an upstream IMSA 104 and a downstream IMSA 110. The upstream IMSA 104 can be classified as a propeller, and the downstream IMSA 110 can also be described as a propeller in this case. In this configuration, the downstream IMSA 110 is disposed within the flow tube 100 of the upstream IMSA 104. In other embodiments, this is not necessary. For example, in other embodiments, the downstream IMSA 110 may extend beyond the flow tube 100 of the upstream IMSA 104. Such a configuration is useful when the downstream IMSA 110 also contributes positively to the net thrust of the IMSA assembly.

[0192] A cross-sectional view of a propeller (such as propeller 104 or upstream IMSA 104) shows a first propeller blade 105 and a second propeller blade 106. The leading edge 109 of the first propeller blade 105 and the trailing edge 108 of the second propeller blade 106 are also visible. A similar configuration is shown in all the figures containing propellers. The propeller blades are structurally supported by a rotor hub 107.

[0193] The downstream IMSA 110 is configured in a similar manner to the upstream IMSA 104, and therefore will not be described in detail. The upstream IMSA 104 and the downstream IMSA 110 are rigidly connected to the boundary device 95 via a connecting device. For clarity, in Figure 7 The device is not shown in the image.

[0194] In other embodiments, the type of IMSA 104 or 110 may differ from the depicted open rotor type. For example, the IMSA may include several open rotors, or may contain at least one ducted fan or a pair of counter-rotating coaxial propellers. The IMSA may also be a gyroscope or a different type of IMSA.

[0195] According to some embodiments, the flow field near the boundary device is intentionally altered by a fluid manipulation device in such a way that the average spatial gradient of the flow velocity in the direction perpendicular to the surface of the boundary device is artificially and intentionally reduced. Shear stress is proportional to the velocity gradient of a Newtonian fluid. Therefore, the viscous shear stress acting on the boundary device is lower compared to prior art embodiments. In some embodiments, the reduction in viscous power consumed by the boundary device is greater than the increase in viscous power consumption by the intentional fluid manipulation device compared to a representative boundary device of the prior art. Therefore, for a certain range of operating conditions, a net reduction in viscous power consumption can be achieved through some embodiments. The optimal configuration of the intentional fluid manipulation device and the boundary device depends on the application and constraints and can be discovered using various methods. For example, many such methods are well known in computational fluid volume mechanics.

[0196] exist Figure 7 In the illustrated embodiment, the fluid manipulation device may include an upstream IMSA 104 and a downstream IMSA 110. This fluid manipulation device is referred to as an "IMSA assembly". The IMSA assembly reduces the average spatial gradient of the flow velocity at the surface of the boundary device 95 and in the direction perpendicular to the surface of the boundary device 95 by intentionally and deliberately altering the spatial distribution of the flow velocity near the surface of the boundary device 95.

[0197] In some embodiments, this change includes reducing the flow velocity magnitude at the outer surface 96 of the boundary device 95 in a fully slip condition. A “fully slip condition” is a theoretical case where there is no boundary layer effect or no-slip condition on a particular surface. In this theoretical case, the boundary layer effect or viscous drag effect of the outer surface 96 on the fluid flow has been mathematically eliminated for the particular surface. The aforementioned velocity reduction occurs relative to local free-flowing fluid flow (i.e., flow around the boundary device 95 without the IMSA components), and in this case, is also calculated for the fully slip condition. The case assuming that the IMSA components have no effect on the fluid flow is called the “reference case.” It should be noted that the nature of the reference case is determined by the case to which it is compared. For example, it should be clear from the context whether a particular reference case should consider conditions with or without slip. The velocity reduction is a result of the combined induced velocities of the upstream IMSA 104 and downstream IMSA 110 at the surface of the boundary device 95 pointing in the positive x-direction of the BAF. This reduction in the flow velocity magnitude at the outer surface 96 of the boundary device 95 in a fully slip condition, compared to the reference case, can reduce the Reynolds number at the outer surface 96. In the no-slip condition, a decrease in the Reynolds number can increase the boundary layer thickness and reduce the average spatial gradient of the flow velocity at the outer surface 96 in the direction perpendicular to the outer surface 96. Therefore, the average viscous shear stress and viscous drag loss at the outer surface 96 can be reduced.

[0198] In some embodiments, although the velocity at the outer surface 96 is reduced in magnitude, it can still have a non-zero component in the negative x direction under the condition of full slip at the outer surface 96. In other words, compared with the reference case with the full slip condition described above, the overall direction of the velocity of the fluid element at the outer surface 96 can remain substantially unchanged under the condition of full slip.

[0199] In the depicted example, the magnitude of the fluid flow at the outer surface 96 of the boundary device 95 has been artificially reduced to essentially zero in the case of full slip. When the magnitude of the fluid velocity at a given surface is zero in the case of full slip, the no-slip case would be equivalent to the full-slip case, all other things being equal. In this case, the viscous resistance on the outer surface 96 would be zero. In this idealized simplification, the flow tube 100 can be considered as an artificial boundary layer of the boundary device 95. It should be noted that this configuration may not be optimal, i.e., minimizing the total viscous resistance, when the viscous resistance effect of the IMSA components is also considered.

[0200] As shown in velocity distribution diagram 102, at the indicated location, the gradient of the fluid velocity magnitude in the direction perpendicular to the outer surface 96 is also essentially zero. In some embodiments, this gradient may be greater than zero on an average value calculated over the entire outer surface 96. However, this average gradient can be smaller compared to a reference case with no-slip conditions.

[0201] In other embodiments, the fluid flow within the flow tube 100 near the boundary device 95 can have different spatial variations or spatial distributions. For example, flow recirculation can exist. In other words, for all or part of the outer surface 96, the fluid velocity on the outer surface 96 adjacent to the boundary device 95 can have a non-zero component in the positive x-direction under full slip conditions. In this case, a stagnant vortex ring (i.e., a ring of circulating flow) will surround all or part of the boundary device 95. Due to symmetry, this vortex ring will have a central axis aligned and coincident with the x-direction of the BAF and will lie in a plane parallel to the yz plane of the BAF. Such a vortex ring will be held in place by the MSA assembly and re-excited by the surrounding flow.

[0202] In some embodiments, the spatial distribution of flow velocity within the flow tube 100 near the boundary device 95 is also intentionally altered. Figure 7 In the illustrated embodiment, the spatial distribution of the induced velocity is configured to produce a substantially linear change in the magnitude of the fluid velocity within the flow tube 100. As shown, the magnitude of the fluid velocity within the flow tube 100 increases substantially linearly in the positive y-direction. In other embodiments, the magnitude of the velocity within the flow tube 100 increases at an incremental rate in the positive y-direction. This configuration can help artificially maintain a low Reynolds number for the boundary layer of the outer surface 96, even if the boundary layer thickness increases in the flow direction (i.e., the negative x-direction of the BAF). The gradual gradient of the velocity magnitude can also minimize frictional heating and turbulence effects within the flow tube 100, thereby reducing drag losses or net power consumption associated with the boundary device 95. In simulations where the flow tube 100 is considered an artificial boundary layer of the boundary device 95, a gradual gradient of the velocity magnitude may be desirable to ensure that the artificial boundary layer is substantially laminar and remains laminar. Furthermore, the gradual increase in velocity magnitude within the flow tube 100 will ensure a minimum momentum transfer from the surrounding flow to the flow tube 100, which will result in a momentum deficit in the flow around the flow tube 100 in the far wake (i.e., in velocity distribution diagram 103) and contribute to the viscous power dissipation associated with the boundary device 95.

[0203] The optimal spatial variation of the fluid velocity within flow tube 100 can be found using existing methods, and it does not have to be linear. For example, among other criteria, it may be desirable to reduce the rate at which the total vorticity released into the fluid from upstream IMSA 104 is reduced.

[0204] The optimal magnitude and direction of the fluid flow at the outer surface 96 under full slip conditions, as well as the magnitude and characteristics of the velocity gradient at the outer surface 96, can be optimized using existing methods for a given flow condition or application. The same methods can also be used to optimize the optimal distribution of fluid velocity within the flow tube 100. The aim of such optimization can be to minimize the total power consumption of the boundary devices and IMSA components.

[0205] The aforementioned velocity distribution near the boundary device 95 is illustrated by a snapshot provided in velocity distribution diagram 102. This velocity distribution differs significantly from the velocity distribution for reference cases with or without slippage. According to some embodiments, this difference is provided by an intentional fluid manipulation device. Figure 7 In the illustrated embodiment, the fluid manipulation device is implemented by an IMSA component. The IMSA component manipulates the fluid by applying a specific spatially induced flow distribution. This induced flow can be viewed as superimposed on the fluid flow under a fully slip condition. In other words, the desired velocity distribution can be generated by calculating the induced flow distribution required to change the flow from the reference condition to the desired velocity distribution and configuring the IMSA component in a manner that achieves the desired induced flow distribution. The degree of viscous drag associated with the outer surface 96 (i.e., the degree of influence of the boundary layer and no-slip condition) is determined or defined by this superimposed flow (i.e., the superposition of the induced flow and the flow under the reference condition). This viscous effect can also be viewed as superimposed on the aforementioned superimposed flow. As described in the following paragraphs, there are several ways to describe the generation or creation of the aforementioned induced velocity distribution of the IMSA component.

[0206] The induced velocity distribution near the boundary device 95 can be considered as being generated by the rate of momentum change of the fluid elements due to their interaction with the upstream IMSA 104. In some embodiments, some fluid elements experience a negative average rate of momentum change during their interaction with the upstream IMSA 104. This rate of momentum change can result in a net reduction in the momentum of the fluid elements near the outer surface 96 of the boundary device 95 after the fluid elements have interacted with the upstream IMSA 104. This reduction occurs relative to a reference case of complete slip condition, i.e., relative to a case where the IMSA components do not interact with the fluid. In other words, in some embodiments, the upstream IMSA 104 is configured to reduce the average momentum of at least a portion of the fluid flow in the far wake of the upstream IMSA 104 under the aforementioned isolation conditions.

[0207] In some embodiments, the reduction in the average momentum of the fluid flow in the far wake occurs at least for streamlines interacting with the outer surface 96 of the boundary device 95 or for streamlines passing near the outer surface 96. This reduction in the momentum of the fluid flow results in a far wake-induced velocity, which has a non-zero component in the upstream direction, as defined by the free flow in the isolated case, compared to the free flow in the isolated case. Since the outer surface 96 of the boundary device 95 is located downstream of the upstream IMSA 104, the flow at or near the outer surface 96 of the boundary device 95 is also subject to an upstream-induced velocity. As described above, the magnitude and spatial distribution of the upstream-induced velocity at or near the outer surface 96 of the boundary device 95 can be configured to reduce the magnitude of the free flow in the fully slipped reference case compared to the fully slipped reference case, and thus reduce the average drag of the boundary device 95 or the average power dissipation associated with the interaction between the boundary device 95 and the fluid.

[0208] Within the simplified framework of the lift line theory, the aforementioned induced velocity distribution can also be generated by free vortices released into the wake by the propeller blades of the upstream IMSA 104. This is similar to the vortex release of a helicopter rotor, a conventional propeller blade, or a wind turbine blade. It should be noted that in some embodiments, vortices released by the downstream IMSA 110 also contribute to the induced velocity near the boundary device 95 (such as at the location in velocity distribution diagram 102).

[0209] The aforementioned induced velocity distribution can also be generated by an appropriate lift or thrust distribution along the propeller blades of the upstream IMSA 104. Since the induced velocity of the upstream IMSA 104 points upstream for at least a portion of the upstream IMSA 104 (i.e., the positive x-direction of the BAF), the operation of the upstream IMSA 104 is analogous to that of a wind turbine. In other words, corresponding to the induced velocity distribution in the wake of the upstream IMSA 104, the thrust experienced by at least a portion of the blades of the upstream IMSA 104 (e.g., the first propeller blade 105) has a non-zero component in the negative x-direction of the BAF, as shown by thrust vector 127.

[0210] At least a portion of the upstream IMSA 104 is configured to extract useful power from the fluid. This power can be extracted in various ways. For example, a generator can be rigidly connected to a drive shaft, which in turn is rigidly connected to the propeller blades of the upstream IMSA 104. Figure 7In the illustrated embodiment, the drive shaft may be parallel to the rotation axis of the propeller blades of the upstream IMSA 104 and parallel to the x-axis of the BAF. In some embodiments, when the upstream IMSA 104 is configured as a conventional propeller, the aforementioned drive shaft is considered as the rotor hub or the propeller shaft of a conventional propeller. Since the electric motor is directly connected to the drive shaft, and the drive shaft is directly connected to the propeller blades, this configuration can also be described as a direct drive configuration.

[0211] In some embodiments, a transmission or gear train may also be present between the generator and the drive shaft. In some embodiments, a clutch may also be present between the propeller and the transmission. In some embodiments, the transmission may be reconfigured. In other words, the gear ratio may be changed, or the gears may be changed. In some embodiments, a mechanical disc brake attached to the drive shaft may also be present, wherein the brake is configured to stop or prevent rotation of the drive shaft. The electricity generated by the generator due to the rotation of the drive shaft may be stored in an energy storage device. For example, such an energy storage device may be a battery or a capacitor. The energy storage device may also include mechanical elements. For example, the energy storage device may include an electric motor or generator configured to accelerate or decelerate the rotational rate of a flywheel that mechanically stores energy in the form of rotational kinetic energy. The electric generator may also power a pump configured to compress and / or expand a gas, such as air, within a tank. It should be noted that at least a portion of the energy stored in the energy storage device can be extracted at a later point in time. Many such energy storage devices or mechanisms are available.

[0212] Electrical power can also be directly transferred to the second actuator, for example, via an electrical conductor. In some embodiments, the second actuator can instantaneously consume power. The second actuator can be any actuator of a device or device assembly associated with the boundary device 95. For example, the second actuator can be used to actuate the downstream IMSA 110. Thus, a portion of the power extracted from the fluid by the upstream IMSA 104 can be transferred to the downstream IMSA 110, whereby the power is reinjected into the fluid. In some embodiments, the second actuator can also be used to... Figure 7 Power is provided by a separate device or mechanism not shown in the diagram.

[0213] The electricity supplied by the upstream IMSA 104 can also be decomposed and used to drive the second actuator, the third actuator, and to increase the energy contained, for example, within an energy storage device. In some embodiments, the power extracted from the fluid by the upstream IMSA 104 and applied to a drive shaft rigidly connected to the propeller blades of the upstream IMSA 104 is mechanically transferred to the downstream IMSA 110. This transfer can be facilitated in several ways. For example, the drive shaft rigidly attached to the propeller blades of the upstream IMSA 104 (referred to as the "upstream drive shaft") can also be rigidly connected to the drive shaft rigidly connected to the propeller blades of the downstream IMSA 110 (referred to as the "downstream drive shaft"). In other words, the upstream drive shaft can be the same as the downstream drive shaft. In such a configuration, the upstream rotor and downstream rotor of the upstream IMSA 104 and the downstream IMSA 110 rotate in the same direction, respectively. In other embodiments, the upstream drive shaft can transfer power to the downstream drive shaft via a transmission, gear train, or a series of gears and a secondary or auxiliary drive shaft. In some embodiments, a clutch may also be present along the load path between the upstream and downstream drive shafts. In some embodiments, the gear ratio or transmission ratio of the mechanical connection between the upstream and downstream drive shafts may be reconfigured. In other words, the gear ratio may be changed, or the gears may be changed.

[0214] In some embodiments, the upstream and downstream rotors of the upstream IMSA 104 and downstream IMSA 110 rotate in opposite directions. This configuration can reduce any power losses associated with the IMSA components. This may be a result of the downstream IMSA 110 eliminating any vortices imposed on the flow by the upstream IMSA 104.

[0215] In some embodiments, the angle of attack of the propeller blades of the upstream IMSA 104 or downstream IMSA 110 relative to the fluid can be controlled by a pitch control mechanism at the rotor hub (such as rotor hub 107). This pitch control mechanism and the associated pitch degree of freedom, or "DOF," may comprise an electric motor and a disc brake. As an alternative to or in parallel with the disc brake, some embodiments may also include a mechanical lock, which can be configured to lock the propeller blade's pitch DOF at a given pitch angle relative to the rotor hub. The pitch control mechanism may also include a hydraulic system and mechanical linkages, such as those found in common pitch mechanisms in conventional helicopters or propellers. The pitch control mechanism and pitch DOF of the propeller blades of the upstream IMSA 104 or downstream IMSA 110 may also be configured to allow the propeller blades to feather. The pitch angle and the rotational rate of the propeller blades can be controlled, thereby allowing adjustment of the IMSA assembly's influence on the fluid. This will allow for optimization of the performance of IMSA components for different flow conditions, such as different free-flow velocities.

[0216] exist Figure 7 In the illustrated IFMA configuration, the downstream IMSA 110 is configured to balance, eliminate, or counteract the effects of the upstream IMSA 104 and boundary device 95 on the fluid. In this way, the fluid velocity distribution in the far wake (as shown in velocity distribution diagram 103) is substantially equal to the free-flow fluid velocity distribution (as shown in velocity distribution diagram 101). During nominal cruise, the power consumed by the downstream IMSA 110 in this process is typically greater than the power extracted by the upstream IMSA 104.

[0217] The downstream IMSA 110 is configured to apply a positive rate of change of momentum to the fluid, i.e., to accelerate the fluid in the negative x-direction. As a result, in the isolated case, the induced velocity of the downstream IMSA 110 in the far wake points in the negative x-direction of the BAF. The induced velocity of the downstream IMSA 110 in the far wake can be considered to counteract the induced velocity of the upstream IMSA 104 in the far wake.

[0218] Within the simplified framework of lift line theory, the desired induced velocity distribution in the far wake of the downstream IMSA 110 can also be considered as generated by free vortices released into the wake by the propeller blades of the downstream IMSA 110. This is similar to the vortex release of helicopter rotors and conventional propeller blades.

[0219] In the isolated configuration, the aforementioned induced velocity distribution of the downstream IMSA 110 can also be considered as being generated by a suitable lift or thrust distribution along the propeller blades of the downstream IMSA 110. Since the induced velocity of the downstream IMSA 110 in the isolated configuration points downstream (i.e., the negative x-direction of BAF) for at least a portion of the downstream IMSA 110, the operation of the downstream IMSA 110 is similar to the operation of a conventional propeller in a conventional fixed-wing aircraft. In other words, corresponding to the induced velocity distribution in the wake of the downstream IMSA 110 in the isolated configuration, the thrust experienced by at least a portion of the blades of the downstream IMSA 110 has a non-zero component in the positive x-direction of BAF, as shown by thrust vector 128.

[0220] It should be noted that in some embodiments, there is no designated downstream IMSA, for example... Figure 7 The downstream IMSA 110. In such embodiments, the power extracted by the upstream IMSA can be stored or used to provide thrust via alternative fluid manipulation devices or methods. It should be noted that Figure 7 The upstream IMSA 104 in the BAF exerts a force in the negative x-direction. During cruise flight, this force will need to be counteracted by adequate thrust to maintain a constant cruise speed for the BAF. This thrust can be provided in several ways. Figure 7 In this embodiment, the thrust is provided by the downstream IMSA 110. In other embodiments, the thrust may be provided by different thrust devices.

[0221] In some embodiments, this thrust can be provided by increasing the radius of the propeller blades of the upstream IMSA. In such embodiments, the length of the propeller blades of the upstream IMSA is greater than... Figure 7 The radius of the flow tube 100 shown. In this case, the propeller blade of the upstream IMSA 104 can have two distinct parts. The first part can be the portion of the propeller blade located within a first internal flow tube, which can have a radius similar to... Figure 7 The flow tube 100 shown has similar dimensions and configuration and achieves the same Figure 7 The flow tube 100 shown serves a similar purpose. The first part of the propeller blades of the upstream IMSA can be configured to achieve the same purpose as... Figure 7The entire upstream IMSA 104 shown serves a similar purpose. The remaining second section of the propeller blades of such an upstream IMSA can be configured to generate the desired thrust described above. The wake of the second section forms an outer flow tube that surrounds or encloses the inner flow tube. The induced velocity of the thrust-generating section of the upstream IMSA can be uniform throughout the entire outer flow tube in the far wake in order to minimize induced power consumption. Thus, the power extracted by the first section of the propeller blades is directly and mechanically transferred to the second section of the propeller blades via a rigid structural connection between the first and second sections of the propeller blades. A portion of the energy loss of the fluid within the inner flow tube is used to generate thrust and increase the energy of the fluid within the outer flow tube. It should be noted that such a configuration will generate a momentum deficit in the wake within the inner flow tube because, as mentioned above, there is no designated downstream IMSA in such embodiments. Such a configuration will result in a non-uniform velocity distribution in the far wake and will therefore be less efficient than a configuration with a substantially uniform velocity distribution throughout the far wake (i.e., in both the inner and outer flow tubes). However, such a configuration can still provide an improvement over embodiments of the prior art due to the recovery of a portion of the energy loss attributable to viscous drag.

[0222] In other embodiments, the aforementioned momentum loss in the internal flow tube is eliminated by adding a downstream IMSA to the above configuration.

[0223] In other embodiments, the downstream IMSA may extend beyond the flow tube 100. For example, the length of the propeller blades of the downstream IMSA may be greater than the radius of the flow tube 100. In this way, the induced power consumption of the downstream IMSA that generates thrust can be reduced. In this configuration, a uniform far-wake induced velocity distribution can be achieved on both the inner and outer flow tubes of the downstream IMSA, which is desirable for minimizing induced power.

[0224] In other embodiments, with Figure 7 Compared to the illustrated embodiments, both the upstream IMSA and the downstream IMSA can include rotor tip extensions. In some such embodiments, the rotor diameters of the upstream IMSA and the downstream IMSA are substantially the same. In other such embodiments, this is not necessarily the case. As previously described, the rotor tip extensions create an outer flow tube surrounding the inner flow tube. The interiors of the rotors of the upstream IMSA and the downstream IMSA can be aligned with... Figure 7The rotor exterior can be configured in the same manner as described in the context of flow tube 100. The rotor exterior can be configured to generate a desired amount of thrust while minimizing total power consumption, which includes form drag and induced drag. For example, the exteriors of the upstream and downstream IMSAs (i.e., the portions associated with the external flow tube) can be configured similarly to a coaxial rotor rotating in opposite directions, with both the upstream and downstream IMSAs generating thrust in the positive x-direction of the BAF. In another instance, the exterior of the upstream IMSA can be configured to generate thrust directed in the positive x-direction of the BAF, and the magnitude of this thrust is greater than the desired thrust required for the exteriors of both the upstream and downstream IMSAs. Therefore, the exterior of the downstream IMSA can be configured to generate thrust directed in the negative x-direction of the BAF. This configuration reduces the induced power consumption associated with the exteriors of the upstream and downstream IMSAs compared to a configuration where the thrust vectors of both the upstream and downstream IMSAs are directed in the positive x-direction of the BAF.

[0225] In some embodiments, there may be more than one single upstream propeller (such as upstream IMSA 104) and more than one single downstream propeller (such as downstream IMSA 110). Several propellers may be located within the flow tube 100 near the boundary device 95. Using several propellers within the flow tube 100 may be desirable in order to maintain a desired velocity distribution within the flow tube 100. For example, consider a cylindrical boundary device with a tapered end, such as the fuselage of a conventional commercial transport aircraft. In this case, it is convenient and desirable to arrange several rotors or propellers along the length of the fuselage. For example, the propellers may be located along the x-axis of the BAF, such as... Figure 6 The location shown is the same as the location of the duct (such as the third IMCA 81). The propeller can be mounted on the fuselage in a manner that maintains the fuselage diameter, i.e., the fuselage is located within the propeller hub or passes through the center of the propeller hub. The circular shape of the fuselage facilitates the rotation of the rotor around the fuselage. The rotor hub can form a rigid ring capable of rotating around the fuselage. For example... Figure 7 As shown, in this configuration, the axis of rotation is parallel to the longitudinal axis of the cylindrical fuselage. Several propeller blades can be attached to the rotor hub and perform the desired fluid flow manipulation. An electric motor can power the rotor hub and extract power from the rotation of the rotor hub relative to the fuselage, depending on whether the rotor is in an "upstream" or "downstream" position or configuration. In such a configuration, at least theoretically, the fuselage can be infinitely long, and during nominal constant speed cruise, the flow field within the flow tube 100 remains constant on average, where the average is calculated along the x-axis of the BAF at a distance between propellers evenly spaced along the fuselage length.

[0226] The length of each rotor blade can be a fraction of the fuselage diameter. In the absence of a slip reference, the length of the rotor blade can be approximately the thickness of the boundary layer at that particular location in the flow. In some embodiments, in the absence of a slip reference, the ratio of the rotor blade length to the maximum thickness of the boundary layer along the outer surface of the boundary device (such as the fuselage) is less than 2. In some embodiments, this ratio is less than 5. In some embodiments, this ratio is less than 10. In some embodiments, this ratio is less than 100.

[0227] Figure 6 A cross-sectional view of another IFMA configuration is shown. Figure 6 Some features of the device shown and some operating principles of the device are related to Figure 7 The devices shown are similar, therefore in Figure 6 The context will not describe it in detail, and vice versa.

[0228] Figure 6 A boundary device 70 moving relative to the surrounding fluid is depicted. The boundary device 70 has a leading edge point 73 and a trailing edge point 74. The leading and trailing edge points can also be edges, such as the leading or trailing edge of a wing or airfoil. In the case of a wing, the leading and trailing edges can be considered as the leading and trailing stagnation lines under specific flow conditions. In this embodiment, the boundary device is a rigid body that can be described as a thin shell, having a closed outer surface 71 and an inner surface 72. In this embodiment, the boundary device 70 has a rotational shape, i.e., it is axisymmetric about an axis passing through the leading edge point 73 and the trailing edge point 74.

[0229] Boundary device 70 can be the hull of a ship or the fuselage of an aircraft. In other embodiments, boundary device 70 can have different geometries. For example, the shape of the boundary device can be similar to that of boundary device 61 shown in FIG. 5. Suitable geometries can be found for any given application. Boundary devices can be manufactured using a variety of existing methods and materials.

[0230] The "Boundary Device Frame" or "BAF" can be defined as follows: The origin is located at the geometric centroid of the volume enclosed by the outer surface 71 of the boundary device 70. The x-axis coincides with the line connecting the leading edge point 73 and the trailing edge point 74, and points towards the leading edge point 73. Unless otherwise specified, the z-axis points perpendicularly to the page of the accompanying drawing.

[0231] Three velocity distribution diagrams 76-78 are shown. Each arrow in the velocity distribution diagram indicates the velocity vector of the incremental fluid element relative to the boundary device, where the incremental fluid element is located at the base of the arrow at the time point in time at which its velocity is measured relative to the boundary device. The line connecting the tips of the arrows in the velocity distribution diagram describes a continuous velocity distribution.

[0232] The boundary device 70 moves relative to the surrounding fluid. In the simplified case illustrated, the free flow velocity is spatially uniform and temporally constant. Figure 6 In the diagram, the free-flowing fluid relative to the boundary device 70 is parallel to the x-axis of the BAF and guided in the opposite direction to the x-axis of the BAF, i.e., from the top to the bottom of the diagram. Upstream of the far end of the boundary device 70, the velocity of the incremental fluid element is approximately equal to the free-flowing velocity. Therefore, the velocities in the velocity distribution diagram 76 are spatially uniform and temporally constant, with magnitude and direction equal to the free-flowing velocity relative to the boundary device.

[0233] Velocity distribution diagram 77 depicts the velocity distribution near the boundary device 70. In this embodiment, a no-slip condition exists on the outer surface 71 of the boundary device 70. In other embodiments, non-zero slip velocity may exist along the outer surface 71. Velocity distribution diagram 77 and... Figure 7 The velocity distribution diagram shown is similar to that in diagram 102. Therefore, in Figure 6 The characteristics of the velocity distribution map and its alternative embodiments will not be described in detail in the context of this document.

[0234] Velocity distribution diagram 78 depicts the velocity distribution in the far wake of boundary device 70. In a simplified ideal case, velocity distribution diagram 78 is essentially equal to velocity distribution diagram 76, as shown below. Figure 6 As shown. It should be noted that there is a momentum deficit due to resistance associated with the IMCA component, for example, this can be caused by pressure resistance or viscous resistance. In other embodiments, there may also be a momentum deficit due to resistance associated with the boundary device 70.

[0235] According to some embodiments, the boundary device (such as boundary device 70) is provided with intentional fluid manipulation means. Figure 6 In the illustrated embodiment, the intentional fluid manipulation device can be described as an IMCA assembly comprising a first IMCA 79, a second IMCA 80, a third IMCA 81, and a fourth IMCA 82. Four IMCAs are shown in this embodiment; however, more or fewer IMCAs may be used.

[0236] Each IMCA (such as the first IMCA 79) can be described as a circular conduit. Figure 6In the illustrated embodiment, each conduit is configured to generate lift with a component in the radially outward direction. The central axis of each circular conduit coincides with and points in the direction of the x-axis of the BAF. Roughly speaking, the effect of the conduit on fluid flow can be considered as generated by vortex rings in the lift line theory. In this simplified model, each vortex ring of each IMCA lies in a plane parallel to the yz plane. When viewed along the positive x-direction, the circulation of each vortex ring surrounds each ring in a clockwise direction. Each IMCA has a leading edge (such as the leading edge 83 of the first IMCA 79) and a trailing edge (such as the trailing edge 89 of the third IMCA 81).

[0237] Streamline 75 describes the boundary of the flow tube, which has a circular cross-section when viewed along the x-direction. Figure 6 The dashed streamline 75 schematically indicates the approximate location of the stagnant streamline of the first IMCA 79, i.e., the streamline incident on the leading edge stagnant line of the first IMCA 79. The volume surrounded by all such streamlines can be described as a flow tube.

[0238] It should be noted that Figure 6 The flow tube 75 shown is merely an example of a specific operating condition and configuration for the IMCA assembly. For other operating conditions, such as different free-flow velocities, the shape of the flow tube 75 may differ. For example, the flow tube 75 may pass through the interior region of the second IMCA 80, rather than also incident on the leading edge stagnation line of the second IMCA 80. To avoid flow separation and the associated increase in pressure drag, it may be desirable that the IMCA is not located within the wake of the upstream IMCA, i.e., along or near the stagnation streamline of the upstream IMCA. However, this can increase the viscous skin frictional drag losses associated with the IMCA assembly.

[0239] Each IMCA in the IMCA assembly is rigidly connected to the boundary device 70 via a connecting device. For clarity, in Figure 6 The device is not shown in the image.

[0240] In other embodiments, the IMCA (such as IMCA 79) may comprise several conduits. In such configurations, the IMCA may be described as a multi-element airfoil, rather than... Figure 6 The illustrated unit airfoil. For example, an IMCA can comprise a four-element airfoil, each section effectively forming a separate duct. Such a configuration can increase the maximum lift coefficient of the IMCA.

[0241] The effect of the IMCA component on fluid flow is to generate a localized induced velocity distribution in the vicinity of the IMCA component. Typically, the induced velocity within the IMCA component (i.e., near the central axis of the IMCA component) has a non-zero component in the positive x-direction of the BAF. The desired induced velocity distribution can be achieved by placing the IMCA (such as the first IMCA 79 and the second IMCA 80) at appropriate locations within the fluid flow and by selecting an appropriate circulation intensity or an appropriate lift per unit circumference.

[0242] According to some embodiments, the IMCA component is configured to reduce the flow velocity at the outer surface 71 of the boundary device 70 in a fully slipped reference condition compared to the fully slipped reference condition. This reduction can result in lower skin frictional resistance at the outer surface 71 in a no-slip condition. For example, this reduction can be caused by a reduction in effective free flow at the outer surface 71, the establishment or maintenance of laminar flow on the outer surface 71, or a reduction in the Reynolds number of the flow at the outer surface 71. For some operating conditions, this reduction in resistance associated with the boundary device 71 can be greater than the increase in resistance of the IMCA component.

[0243] Figure 8 This is a cross-sectional view of IFMA Configuration 150. The center of mass of IFMA Configuration 150 moves at a velocity in an inertial frame of reference, where the magnitude and direction of this velocity are constant in space and time. This velocity is aligned with the X-axis, i.e., pointing in the positive X direction.

[0244] An upstream IMSA 151 exists, which in this embodiment can be described as a propeller. A cross-sectional view of the upstream IMSA 151 shows a first propeller blade 152 and a second propeller blade 154. The trailing edge 153 of the first propeller blade 152 and the leading edge 155 of the second propeller blade 154 are also visible. The propeller blades are structurally supported by a rotor hub 156. The thrust of the IMSA 151 is represented by a thrust vector 183. At station 179, in this embodiment, a positive rate of change of momentum is applied to the fluid via the upstream IMSA 151.

[0245] A downstream IMSA 166 exists, which in this embodiment can be described as a propeller. A cross-sectional view of the downstream IMSA 166 shows a first propeller blade 167 and a second propeller blade 169. The trailing edge 168 of the first propeller blade 167 and the leading edge 170 of the second propeller blade 169 are also visible. The propeller blades are structurally supported by a rotor hub 171. The thrust of the IMSA 166 is represented by a thrust vector 184. At station 181, a negative rate of change of momentum is applied to the fluid via the downstream IMSA 166. Downstream of the IFMA configuration 150, the direction of the flow within the flow tube 176 relative to the IFMA configuration 150 is indicated by arrow 185.

[0246] An intermediate IMSA 161 is also shown. In this embodiment, the intermediate IMSA 161 can be described as a wing. For simplicity, the wing 161 is a straight wing. For example, the wing can be rigidly attached to the fuselage. For clarity, the fuselage is not shown. The intermediate IMSA 161 can be configured in a manner similar to the fixed wing of a conventional fixed-wing aircraft. The intermediate IMSA 161 generates lift in the positive Y direction and the negative X direction. It should be noted that, for illustrative purposes, the relevant deflection of the flow direction within the flow tube 176 has been amplified.

[0247] The intermediate IMSA 161 includes an outer surface 162, a trailing edge 165, and a matrix material 164. The matrix material 164 may comprise a metal such as aluminum or steel, or a composite material such as glass fiber or carbon fiber. The upstream IMSA 151 is rigidly attached to the intermediate IMSA 161 via a hollow link 157 having an outer surface 158. The downstream IMSA 166 is rigidly attached to the intermediate IMSA 161 via a link 172 having an outer surface 173.

[0248] In other embodiments, link 157 or link 172 is rotatably connected to the intermediate IMSA 161 or an associated intermediate support device. In some embodiments, link 157 or link 172 is rotatably connected to hub 157 or hub 171, respectively. Rotary connections allow this configuration to adapt to different operating conditions. During cruise or maneuvering, the rotary connection can facilitate control of the pitch angle of the intermediate IMSA 161 and any associated devices, such as the fuselage.

[0249] In this particular embodiment, the magnitude of the upstream thrust vector 183 is greater than the magnitude of the downstream thrust vector 184. Therefore, the upstream IMSA 151 and the downstream IMSA 166 generate a net thrust with a non-zero component in the positive X direction. This net thrust thus helps to counteract any traction drag acting on the IFMA configuration 150. In other embodiments, the magnitudes of these thrust vectors may be substantially the same. In other embodiments, the magnitude of the upstream thrust vector 183 is smaller than the magnitude of the downstream thrust vector 184.

[0250] The upstream IMSA 151 is configured to increase the local free-flow velocity of the intermediate IMSA 161 to a value greater than the free-flow velocity of the intermediate IMSA 161. The downstream IMSA 166 is configured to recover at least a portion of the excess thrust and excess energy transferred to the fluid by the upstream IMSA 151 throughout the process. Compared to a baseline case where the same intermediate IMSA 161 produces the same amount of lift without the upstream IMSA 151 and downstream IMSA 166, the induced drag of the intermediate IMSA 161 can be reduced.

[0251] As a result, the average flow velocity at station 180 is greater than that at stations 178 and 182. The flow tube 176 at station 180 has a smaller flow cross-sectional area than the flow tubes at stations 182 or 178. The increase in the flow cross-sectional area of ​​the flow tube 176 at station 182 compared to station 180 can be considered as an increase in the aspect ratio or span of the intermediate IMSA 161.

[0252] Figure 9 yes Figure 8 The image shows a front view of the IFMA configuration 150. When viewed in the negative X direction, the upstream IMSA 151 and downstream IMSA 166 can rotate counterclockwise. Alternatively, the upstream and downstream IMSA can rotate in opposite directions.

[0253] In other embodiments, the upstream IMSA or downstream IMSA may comprise a plurality of individual propellers. These propellers may be offset from each other in the flow direction. For example, the upstream IMSA or downstream IMSA may comprise coaxial propellers rotating in opposite directions. In some embodiments, the upstream IMSA or downstream IMSA may comprise a plurality of propellers distributed along the width of the flow tube. In other words, the propellers may also be offset from each other in a direction transverse to the flow direction.

[0254] The path followed by the tip of the propeller blade of the upstream IMSA 151 is shown by dashed line 186. Figure 9 The dashed line 187 shows the path followed by the tip of the propeller blade of the downstream IMSA 166.

[0255] Figure 10 , Figure 11 , Figure 12 and Figure 13 Perspective, side, top, and rear views of the IFMA configuration 200, including the intermediate IMSA 201, are shown. For simplicity, the intermediate IMSA 201 can be configured as a straight wing with an elliptical aspect ratio, constant airfoil shape, and zero twist. For example, the wing can be rigidly attached to the fuselage. The fuselage is not shown for clarity. The intermediate IMSA 201 can be configured in a similar manner to the intermediate IMSA 161, or vice versa. The intermediate IMSA 201 can be configured like a wing or horizontal rudder of an aircraft or ship. The intermediate IMSA 201 includes an outer surface 202 and a trailing edge 205.

[0256] IMCA 206 is configured to increase the local free flow of intermediate IMSA 201. In other words, the flow velocity at station 224 is artificially increased by IMCA 206 compared to the flow velocity at upstream station 223 or downstream station 224. IMCA 206 can be considered as a conduit.

[0257] IMCA 206 is rigidly attached to IMSA 201. IMCA 206 includes an outer surface 207 and a trailing edge 210. In this embodiment, when viewed in the flow direction, IMCA 206 is rectangular in shape, as shown below. Figure 13 As shown. In other embodiments, the shape of IMCA206 may be elliptical or circular. In other embodiments, IMCA may describe a mirrored bell shape, wherein the mirror plane coincides with the wingspan of the wing.

[0258] IMCA 206 can be configured not to release any vorticity within the framework of lift line theory. In other words, the circulation associated with IMCA 206 is constant along the wingspan of IMCA 206. In other embodiments, IMCA 206 may also release vortices. For example, IMCA 206 may be configured to contribute to the net lift of IFMA configuration 200. In such embodiments, IMCA 206 can be viewed as a conventional closed wing or annular wing, with the constant wingspan circulation added to the boundary vorticity released into the far wake of IMCA. In other words, IMCA can be viewed as a superposition of IMCA and IMSA. In some embodiments, the intermediate IMSA 201 may also be described as a closed wing.

[0259] The variation of the torsion angle along the span of IMCA 206 is a result of the influence of IMSA 201 on the flow field and the requirements of the boundary vorticity or circulation of IMCA 206.

[0260] In some embodiments, IFMA configuration 200 may include several independent closed airfoils configured in a manner similar to IMCA 206. These independent IMCAs may be offset in the flow direction in a manner similar to that of a multi-element airfoil. Individual independent IMCAs may also be offset in a direction perpendicular to the local flow direction. IMCAs may also be considered to be located within another IMCA. For example, a first circular IMCA may be considered to be concentrically arranged with a second circular IMCA.

[0261] Streamline 222 illustrates the reduction in the cross-sectional area of ​​the flow tube surrounded by IMCA 206 at station 224 due to the accelerated flow via IMCA 206. The cross-sectional area of ​​this flow tube is larger at station 225, corresponding to the larger effective span of IMSA 201.

[0262] Figure 14 This is a cross-sectional view of IFMA configuration 240, which is used in conjunction with... Figure 10The IFMA200 shown is configured in a similar manner. In this embodiment, the conduit 241 releases the eddies into the wake. Therefore, the conduit 241 is also referred to as IMSA 241. IMSA 241 can be considered as a superposition of IMCA and IMSA. IMSA 241 is configured to increase the local free-flow velocity of the intermediate IMSA 247.

[0263] In this embodiment, IMSA 241 is substantially axially symmetrical. IMSA 241 includes an outer surface 242, an inner surface 243, a substrate material 246, and a trailing edge 244. The substrate material 246 can be configured in a similar manner to substrate material 164. The intermediate IMSA 247 is configured in a similar manner to the intermediate IMSA 201. The intermediate IMSA 247 includes an outer surface 248 and a trailing edge 250.

[0264] Flow tube 254 surrounds all streamlines, which encircle IMSA 241, i.e., pass through the interior of IMSA 241. The cross-sectional area of ​​the flow tube at upstream station 255 is larger than that at station 256, while the cross-sectional area of ​​station 256 is smaller than that at downstream station 257.

[0265] Figure 15 This is another perspective view of IFMA configuration 270. Figure 15 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 7 The apparatus shown in ) is similar, therefore in Figure 15 The context will not describe it in detail, and vice versa.

[0266] IFMA Configuration 270 is depicted as a fixed-wing aircraft, such as a commercial transport aircraft or a jet airliner, such as a Boeing 737 or Airbus A320. It has a fuselage 293, a left wing 300 and a right wing 299, a vertical tail 301 including a rudder, and a left horizontal stabilizer 304 and a right horizontal stabilizer for all-flight operations. During nominal level cruise, the flight direction of IFMA 270 is substantially in the direction of thrust vector 292. During nominal level cruise, the direction of airflow around Configuration 270 relative to the free flow of Configuration 270 is indicated by arrow 305.

[0267] An upstream IMSA 271 exists, which in this embodiment can be described as a ducted fan. In this embodiment, the duct is configured to slow the flow before encountering a fan disk located within the fan. In some embodiments, this can be used to avoid or mitigate wave drag losses associated with the fan disk. The upstream IMSA 271 includes a duct 272 and a fan disk. The upstream IMSA 271 is configured to apply a force to an IFMA configuration 270, directed in the same direction as the mean free flow relative to the IFMA 270, as indicated by thrust vector 281. The upstream IMSA 271 is configured to extract energy from the surrounding fluid. The IFMA 270 is configured to transfer at least a portion of the energy to the downstream IMSA 282. As described above, the transfer can be facilitated by connecting the fan disk of the upstream IMSA 271 to the fan disk of the downstream IMSA 282 via a mechanical drive shaft. The fan disk of the upstream IMSA 271 can transfer power to the fan disk of the downstream IMSA 282 via, for example, a direct, rigid mechanical connection. The fan disk of the upstream IMSA 271 can transmit power to the fan disk of the downstream IMSA 282 via a drive shaft and gear train. The drive shaft can pass through the fuselage 293. The fan disk of the upstream IMSA 271 can transmit power to the fan disk of the downstream IMSA 282 via a generator, which transmits power to an electric motor via wires or conductors, and the electric motor then transmits power to the fan disk of the downstream IMSA 282. The upstream IMSA 271 and downstream IMSA 282 are rigidly attached to the fuselage 293.

[0268] In some embodiments, the downstream IMSA 282 may be described as a turbofan engine. Where power is transferred from the upstream IMSA 271 to the downstream IMSA 282, the downstream IMSA 282 may be described as a hybrid electric turbofan engine. In other embodiments, the downstream IMSA 282 may be described as a turbojet engine. The downstream IMSA 282 includes a duct 283. The downstream IMSA 282 is configured to apply a force to embodiment 270 directed in the opposite direction to the mean free flow relative to the IFMA configuration 270, as indicated by thrust vector 292. In this embodiment, the thrust magnitude of the downstream IMSA 282 is greater than the thrust magnitude of the upstream IMSA 271. Therefore, the downstream IMSA 282 is configured to meet any unresolved thrust requirements of the IFMA configuration 270. In other embodiments, at least one separate propulsion unit or engine may be attached to at least one wing. For example, such a separate engine may be a conventional turbofan or a hybrid electric turbofan.

[0269] The upstream IMSA 271 can be configured to artificially reduce at least the local free flow of the fuselage 293, and the downstream IMSA 282 is configured to counteract at least a portion of the reduction in velocity in the wake of the fuselage 293 and near the fuselage 293.

[0270] In some embodiments, the upstream IMSA 271 can be considered as generating an artificial boundary layer for the fuselage 293, wherein the boundary layer is generally surrounded by flow channels passing through the interior of the conduit 272. It should be noted that the fuselage 293 and the artificial boundary layer can also be considered as being surrounded by a natural boundary layer. The upstream IMSA 271 is configured to alter the velocity distribution within the artificial boundary layer or near the wetted surface of the fuselage 293 in such a way that it reduces the overall drag of the fuselage 293 and the IFMA configuration 270 compared to the baseline case where the upstream IMSA 271 is absent, i.e., compared to the case where the fuselage is surrounded only by a natural boundary layer. For example, the reduction in drag can include a reduction in viscous drag, and / or a reduction in wave drag or compressive drag. The reduction in drag is associated with altering the spatial distribution of fluid velocity relative to the fuselage 293 through the upstream IMSA 271 and, to a lesser extent, the downstream IMSA 282.

[0271] Reducing the magnitude of the local free-flow fluid velocity in the fuselage 293 via the upstream IMSA 271, reducing the fluid velocity at and relative to the wetted surface of the fuselage 293, and generating a more favorable velocity distribution near the wetted surface of the fuselage 293 can contribute to the reduction of viscous drag. For example, a more favorable velocity distribution may include a reduced peak spatial fluid velocity gradient or a reduced spatial average magnitude of the spatial fluid velocity gradient near the IMSA configuration 270.

[0272] The reduction in wave drag can result from a smoother change in the fluid flow direction as the fluid flows around the IFMA configuration 270, or from a smoother displacement of the fluid by the IFMA configuration 270. This is facilitated by the deceleration of the fluid flow by the upstream IMSA 271 and the acceleration of the fluid flow by the IMSA 282. Therefore, the intensity of the disturbance to the fluid flow by the IFMA configuration 270 can be reduced, which can reduce the wave drag associated with the IMMA configuration 270.

[0273] The reduction in drag can decrease the power consumption of the IFMA configuration 270 compared to the baseline case, or, for a given power consumption, allow the IFMA configuration 270 to move faster relative to the fluid. This can increase the range or maximum speed of the IFMA configuration 270.

[0274] Figure 16 This is a top-down view of another IFMA configuration 315. Figure 16 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 3The apparatus shown in ) is similar, therefore in Figure 16 The context will not describe it in detail, and vice versa.

[0275] IFMA configuration 315 can be described as a quadcopter helicopter or quadcopter aircraft. Embodiment 315 can also be described as an octocopter or multi-rotor. IFMA configuration 315 includes four IMSA components, such as IMSA components 316, 339, 362, and 385. Each IMSA component includes an upstream IMSA (such as upstream IMSA 365 of IMSA component 362) and a downstream IMSA (such as downstream IMSA 375 of IMSA component 362).

[0276] Each upstream or downstream IMSA can be described as a propeller. Each propeller may include a first propeller blade (such as the first propeller blade 377 of the downstream IMSA 375) and a second propeller blade (such as the second propeller blade 378 of the downstream IMSA 375). In other embodiments, the propeller may include at least one blade or only one blade. In other embodiments, the propeller may include at least three blades. A propeller hub (such as propeller hub 379 or 369) connects each propeller to a drive shaft or actuator.

[0277] IFMA configuration 315 is displayed as hovering. The flow induced by the IMSA component points in a vertically downward direction, essentially aligned with the thrust vector 380.

[0278] An upstream IMSA (such as upstream IMSA 365) is configured to generate thrust acting on IFMA configuration 315 in an upward direction, as shown by thrust vector 370 or 347. A downstream IMSA (such as downstream IMSA 375) is configured to generate thrust acting on configuration 315 in a downward direction, as shown by thrust vector 380 or 357.

[0279] Compared to the case where the IMSA assembly comprises only one IMSA (i.e., only the upstream IMSA), the upstream IMSA is configured to increase the local free-flow velocity relative to itself. The corresponding downstream IMSA is configured to counteract any excess momentum in the fluid flow in the wake of the upstream IMSA. It should be noted that during nominal hover, the sum of the net thrust generated by all four IMSA assemblies is substantially equal to the weight of the IFMA configuration 315. During nominal hover, the net thrust generated by any one IMSA assembly is substantially equal to the net thrust generated by any of the other four IMSA assemblies. The downstream IMSA is configured to generate thrust acting on embodiment 315 in the direction of fluid flow relative to embodiment 315 through the upstream IMSA, as indicated by thrust vectors 380 or 357. During nominal hover, the magnitude of the thrust vector of the downstream IMSA is smaller than the magnitude of the thrust vector of the corresponding upstream IMSA.

[0280] Each IMSA component in IFMA configuration 315 also includes a nacelle, such as nacelle 340, which houses actuators, generators, gearboxes, or drive shafts that facilitate the transfer of energy from the downstream IMSA to the upstream IMSA. It should be noted that a downstream IMSA of the first IMSA component can also transfer power to the upstream IMSA of the second IMSA component.

[0281] exist Figure 16 In the configuration shown, the induced power consumption of the IMSA component is lower than that of the equivalent baseline or reference configuration, where the effect of the downstream IMSA on the fluid is negligible, meaning the thrust of the upstream IMSA is essentially equal to the net thrust requirement. In the baseline configuration, the IMSA component can be considered to consist only of the upstream IMSA. It should be noted that, as mentioned above, in some embodiments, the IMSA (such as the upstream IMSA) may include several propellers or thrust devices. In this case, the baseline configuration is the same as that of a conventional quadcopter helicopter.

[0282] Each IMSA assembly is rigidly connected to the fuselage 408 via a beam. Each beam is enclosed in an aerodynamic or hydrodynamic fairing, such as beam fairing 341. In some embodiments, the beam fairing is rotatably connected to the beam, i.e., capable of rotating relative to the fuselage 408 and the corresponding nacelle. In some embodiments, at least one beam fairing can be used to generate lift during nominal level cruise, wherein the lift is generated in a manner similar to that of a conventional fixed-wing aircraft, wherein the fuselage long axis is oriented in a substantially horizontal direction, i.e., the direction of motion in the inertial frame, and at least one IMSA assembly is configured to generate net thrust to counteract the drag acting on the IFMA configuration 315. It should be noted that in some embodiments, the pitch angle of the propellers of some IMSAs can be varied. It should be noted that during cruise, the propellers of some IMSA assemblies can be feathered.

[0283] In some embodiments, the upstream IMSA may be powered by an electric motor. In some embodiments, the upstream IMSA may be powered by a brushless DC motor containing permanent magnets. In some embodiments, the IMSA assembly may be powered by an AC induction motor. In some embodiments, the drive shaft of the upstream IMSA is rigidly connected to the drive shaft of the corresponding downstream IMSA. In some embodiments, an actuator powering the drive shaft is rigidly connected to the drive shaft in a direct drive configuration. In some embodiments, the actuator is connected to the drive shaft via a clutch or gear train. For example, power may be provided by a battery, an internal combustion engine, or a turboshaft engine. Actuators powering one or more IMSA assemblies may also be located within the housing 408. For example, power may be transferred mechanically or electrically from such actuators to the IMSA assemblies.

[0284] In some implementations, the upstream or downstream IMSA includes several propellers. For example, the upstream or downstream IMSA may include at least two coaxial propellers rotating in opposite directions or in the same direction.

[0285] It should be noted that the propellers of the upstream IMSA and the corresponding downstream IMSA do not need to be in phase and do not need to rotate at the same angular velocity during nominal operation. In some embodiments, there exists an optimal phase angle for a given interval between the upstream and downstream IMSA, where optimality may refer to minimizing vehicle operating costs or maximizing vehicle durability.

[0286] Figure 17 This is another IFMA configuration 425 oblique top view. Figure 17 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 3 The apparatus shown in ) is similar, therefore in Figure 17 The context will not describe it in detail, and vice versa.

[0287] The IFMA configuration 425 can be described as a conventional helicopter. The IFMA configuration 425 includes a fuselage 448 with windows 449 and a tail rotor assembly 451.

[0288] IFMA configuration 425 is displayed as being in nominal hover, where the induced flow is directed vertically downward, as shown in flow direction 456.

[0289] The upstream IMSA 426 is configured to generate thrust acting on the IFMA configuration 425 in an upward direction, as shown by thrust vector 434 associated with the first rotor blade 427 or thrust vector 435 associated with the second rotor blade 430. The first blade 427 and the second blade 430 are connected to the drive shaft via a rotor hub 433. The drive shaft may be surrounded by an aerodynamic fairing 436.

[0290] The downstream IMSA 437 is configured to generate thrust acting on embodiment 425 in a downward direction, as shown by thrust vector 445 associated with the first rotor blade 438 or thrust vector 446 associated with the second rotor blade 441. The first blade 438 and the second blade 441 are connected to a drive shaft via rotor hub 444. The drive shaft may be surrounded by an aerodynamic fairing 447. In some embodiments, the drive shafts of the upstream IMSA 426 and the downstream IMSA 437 are identical. In other embodiments, the drive shaft of the upstream IMSA 426 passes coaxially through the center of the drive shaft of the downstream IMSA 437. In other embodiments, a fuselage 448 is located between the upstream IMSA 426 and the downstream IMSA 437.

[0291] The IFMA Configuration 425's main rotor system can be described as an IMSA assembly comprising the upstream IMSA 426 and the downstream IMSA 437. Figure 17 In the hovering configuration shown, the induced power consumption of the IMSA component is lower than that of the equivalent baseline or reference configuration, where the impact of the downstream IMSA on the fluid is negligible, meaning the thrust of the upstream IMSA is essentially equal to the net thrust requirement. In the baseline configuration, the IMSA component can be considered to consist only of the upstream IMSA. In this case, the baseline configuration is the same as that of a conventional helicopter.

[0292] Within the nominal level cruise operating conditions, at least a portion of the downstream IMSA 437 is no longer located in the wake of the upstream IMSA 426. When this portion is sufficiently large, the downstream IMSA 437 can feather. In some embodiments, feathering of the downstream IMSA 437 may involve reducing the angular velocity of the rotor blades to zero. In some embodiments, the rotor blades of the downstream IMSA 437 are folded. For example, the rotor blades may be folded into an aerodynamic fairing for nominal level cruise. In other embodiments, during nominal level cruise, the downstream IMSA 437 may be configured to generate thrust or lift with a positive component along the lift vector of the upstream IMSA 426. In this respect, the downstream IMSA 437 and the upstream IMSA 426 may operate or be configured in a manner similar to the rotors of a coaxial helicopter in the prior art.

[0293] It should be noted that the principles of some embodiments can also be applied to tiltrotor aircraft. For example, a single rotor of a tiltrotor aircraft can be replaced by two rotors separated by a support shaft, similar to two rotors, namely the upstream IMSA 426 and the downstream IMSA 437, as shown below. Figure 17 As shown. In this way, some of the advantages of the embodiments can be applied to cruise flight and hovering flight.

[0294] Figure 18 This is another oblique side view of IFMA configuration 470. Figure 18 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 3 The apparatus shown in ) is similar, therefore in Figure 18 The context will not describe it in detail, and vice versa.

[0295] The IFMA configuration 470 can be described as a wind turbine. Wind direction is indicated by arrow 501. The IFMA configuration 470 includes a vertical support 496 rotatably connected to a horizontal nacelle 495, with the rotation axis parallel to the vertical axis. An upstream IMSA 471 and a downstream IMSA 483 are rotatably connected to the nacelle 495, with their rotation axes coaxial and parallel to the horizontal axis.

[0296] In this embodiment, the upstream IMSA 471 can be described as a propeller and includes a first blade 472, a second blade 478, and a third blade 475. Each blade is rotatably connected to a rotor hub 481, with the axis of rotation substantially parallel to the long axis of the blade. The pitch angle of each rotor blade can be adjusted according to wind conditions to optimize the performance of the wind turbine, where performance can refer to, for example, the power extracted from the wind. The upstream IMSA 471 is configured to accelerate the fluid flow at the location of the downstream IMSA 483, i.e., to increase the magnitude of the fluid velocity relative to the inertial frame. The upstream IMSA 471 applies a thrust in the upstream direction in embodiment 470, as indicated by thrust vector 482.

[0297] The downstream IMSA 483 in this embodiment can be described as a propeller and includes a first blade 484, a second blade 490, and a third blade 475. Each blade is rotatably connected to a rotor hub 493, with the axis of rotation substantially parallel to the long axis of the blade. The pitch angle of each rotor blade can be adjusted. The downstream IMSA 483 is configured to slow the fluid flow downstream of the downstream IMSA 483, i.e., reduce the magnitude of the fluid velocity relative to the inertial frame. The downstream IMSA 483 applies a downstream thrust at the IFMA configuration 470, as shown by thrust vector 494. A portion of the power extracted from the fluid by the downstream IMSA 483 is transferred to the upstream IMSA 471, and a portion of the transferred power is applied to the fluid by the upstream IMSA 471. As described above, this power can be transferred mechanically or electrically, for example.

[0298] The rotor system of IFMA Configuration 470 can be described as an IMSA assembly comprising upstream IMSA 471 and downstream IMSA 483. Figure 18In the configuration shown, the power extracted by the IMSA component from the motion of the surrounding fluid (e.g., wind or water flow) is greater than the power extracted by the equivalent baseline or reference configuration, where the effect of the upstream IMSA on the fluid is negligible, i.e., the thrust of the downstream IMSA in the baseline configuration is essentially equal to... Figure 18 The IFMA configuration shown has a net thrust of 470. In the baseline configuration, the IMSA component can be considered as containing only the downstream IMSA. For the depicted configuration, the baseline configuration is the same as that of a conventional wind turbine. The performance improvement is particularly significant at low wind or low flow rates.

[0299] Figure 19 This is a side view of another IFMA configuration 515. Figure 19 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 7 The apparatus shown in ) is similar, therefore in Figure 19 The context will not describe it in detail, and vice versa.

[0300] The IFMA configuration 515 can also be described as a vessel having a hull 536, a superstructure 539 above the water surface 548, and a rudder 542 below the water surface.

[0301] The upstream IMSA 516 can be described as a propeller having at least a first propeller blade 517 and a second propeller blade 520. Each propeller blade is rotatably connected to a hub 523, with the axis of rotation parallel to the long axis of the blade. The pitch of each propeller blade can be adjusted according to the operating conditions of the vessel. The upstream IMSA 516 is supported by a fairing 525, which in some embodiments surrounds a drive shaft rigidly connected to the hub 523. In some embodiments, the hub 523 is connected to a generator in a direct-drive configuration. The upstream IMSA 516 is configured to slow the flow and reduce local free-flow flow on the hull 536. Therefore, the upstream IMSA 516 applies thrust to the IFMA configuration 515 in the direction of fluid flow relative to the hull 536, as indicated by thrust vector 524.

[0302] The downstream IMSA 526 can be described as a propeller having at least a first propeller blade 533 and a second propeller blade 530. Each propeller blade is rotatably connected to a hub, with the axis of rotation parallel to the long axis of the blade. The pitch of each propeller blade can be adjusted according to the operating conditions of the vessel. The downstream IMSA 526 is supported by a fairing 535, which in some embodiments surrounds a drive shaft rigidly connected to the hub. In some embodiments, the hub is connected to an electric motor in a direct-drive configuration. The downstream IMSA 526 is configured to accelerate flow. Therefore, the downstream IMSA 526 applies thrust to the IFMA configuration 515 in the direction opposite to the fluid flow relative to the hull 536, as indicated by thrust vector 534.

[0303] The upstream IMSA 516 can reduce the drag of the IFMA configuration 515. This drag reduction can include a reduction in the viscous drag of the hull 536 and / or a reduction in the gravitational wave drag of the hull 536. The drag reduction is associated with altering the spatial distribution of fluid velocity relative to the hull 536 via the upstream IMSA 516. Reducing the magnitude of the local free-flow fluid velocity of the hull 536, reducing the fluid velocity at and relative to the wetted surface of the hull 536, and generating a more favorable velocity distribution near the wetted surface of the hull 536 via the upstream IMSA 516 can contribute to the reduction of viscous drag. For example, a more favorable velocity distribution can include a reduced peak spatial fluid velocity gradient or a reduced spatial average magnitude of the spatial fluid velocity gradient near the IFMA configuration 515. The reduction in wave drag can result from a smoother change in the direction of fluid flow as the fluid flows around the IFMA configuration 515, or from a smoother displacement of the fluid by the IFMA configuration 515 due to the deceleration of the fluid flow by the upstream IMSA 516 and the acceleration of the fluid flow by the IMSA 526. Therefore, the intensity of the disturbance to the fluid flow by the IFMA configuration 515 can be reduced. In some embodiments, for example, the upstream IMSA 516 can be configured to perform a function similar to that of a spherical bow found in conventional hull designs.

[0304] Figure 20 This is a side view of another IFMA configuration 560. Figure 20 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 7 The apparatus shown in ) is similar, therefore in Figure 20 The context will not describe it in detail, and vice versa.

[0305] The IFMA configuration 560 can also be described as a train or truck, and includes a first car 561, a second car 576, a third car 577, a fourth car 589, and a fifth car 591. Each car is supported by wheels (such as wheels 563), which facilitate movement of the car relative to the road or track 605. Each car is connected to an adjacent car via connectors (such as connectors 566). The cars are rotatably connected to the wheels via support structures (such as support structures 578).

[0306] The upstream IMSA 567 can be described as a propeller having at least a first propeller blade 568 and a second propeller blade 571. Each propeller blade is rotatably connected to a hub 574, with rotation parallel to the long axis of the blade. The pitch of each propeller blade can be adjusted according to the operating conditions of the vehicle. The upstream IMSA 567 is configured to slow the flow and reduce the local free flow of the remaining vehicle. Therefore, the upstream IMSA 567 applies thrust to the IFMA configuration 560, which is directed in the direction of fluid flow relative to the IFMA configuration 560, as indicated by thrust vector 575.

[0307] The downstream IMSA 596 can be described as a propeller. In the IFMA configuration 560, the first carriage 561 can be the same as the fifth carriage 591 to reduce the manufacturing cost of embodiment 560. It should be noted that the first carriage 561 operates in a different manner than the fifth carriage 591. The downstream IMSA 596 is configured to accelerate the flow. Therefore, the downstream IMSA 596 applies thrust to the IFMA configuration 560 in the opposite direction of the fluid flow relative to embodiment 560, as shown by thrust vector 604.

[0308] Due to the length of the IFMA configuration 560, the drag reduction effect of the upstream IMSA 574 decreases with increasing distance from the upstream IMSA 574 along the length of embodiment 560. This could be due to viscous effects, for example. The intermediate IMSA 580 is configured to correct any distortions in the actual velocity distribution compared to an ideal velocity distribution near the outer surface of the IFMA configuration 560. The intermediate IMSA 580 includes at least a first propeller blade 581 and a second propeller blade 584. Each propeller blade is rotatably connected to a hub 587, with the axis of rotation parallel to the long axis of the blade. The pitch of each propeller blade can be adjusted according to the operating conditions of the vehicle. The intermediate IMSA 580 is configured to slow the flow and reduce local free-flow of the remaining vehicle. Therefore, the intermediate IMSA 580 applies thrust to the IFMA configuration 560 in the direction of fluid flow relative to embodiment 560, as indicated by thrust vector 588.

[0309] In some embodiments, the sum of the traction resistance acting on the vehicle portion between the intermediate IMSA 580 and the downstream IMSA 596 and the thrust or drag acting on the intermediate IMSA 580 is less than the traction resistance acting between the third and last cars in the embodiment without an intermediate IMSA (i.e., when the third car is configured in a manner similar to the second car 576). For some embodiments, for some operating conditions, the net traction resistance acting on the embodiment without a dedicated intermediate IMSA (such as intermediate IMSA 580) is greater than the net traction resistance acting on the IFMA configuration 560. It should be noted that some embodiments may include several intermediate IMSAs configured in a manner similar to intermediate IMSA 580. It should be noted that several cars (such as car 576) may be located between the upstream IMSA, intermediate IMSA, or downstream IMSA. In some embodiments, the connection between adjacent cars includes an aerodynamic fairing configured to allow the cars to rotate relative to each other during curves or bends in a road or track.

[0310] The upstream IMSA 567 and intermediate IMSA 580 can be configured to extract energy from the surrounding fluid, while the downstream IMSA 596 can be configured to apply at least a portion of the extracted energy to the fluid surrounding the IFMA configuration 560. It should be noted that embodiments similar to the IFMA configuration 560 may include a separate traction motor, which is configured to facilitate propulsion of the embodiment by transmitting torque to at least one wheel. In other embodiments, any unresolved thrust requirements of the embodiment are provided by the downstream IMSA 596.

[0311] Figure 21 This is a side view of another IFMA configuration 620. Figure 21 Some features of the device shown and some operating principles of the device are consistent with other accompanying drawings (especially...). Figure 7 and Figure 20 The apparatus shown in ) is similar, therefore in Figure 21 The context will not describe it in detail, and vice versa.

[0312] The IFMA configuration 620 can also be described as a train or truck, and includes a first car 621, a second car 632, a third car 633, a fourth car 634, a fifth car 646, and a sixth car 647. Each car is supported by wheels (such as wheels 623), which facilitate movement of the car relative to a road or track 657. Each car is connected to adjacent cars via connectors (such as connectors 626). The cars are rotatably connected to the wheels via support structures.

[0313] The upstream IMSA 627 can be described as a ducted fan comprising a duct 628 surrounding a propeller having at least a first propeller blade and a second propeller blade. Each propeller blade is rotatably connected to a hub, with the axis of rotation parallel to the long axis of the blade. The pitch of each propeller blade can be adjusted according to the operating conditions of the vehicle. The upstream IMSA 627 is configured to slow the flow and reduce local free flow of the remaining vehicle. Therefore, the upstream IMSA 627 applies thrust to embodiment 620 in a direction relative to the fluid flow of embodiment 620, as indicated by thrust vector 631.

[0314] The downstream IMSA 652 can be described as a ducted fan. In the IFMA configuration 620, the first compartment 621 is identical to the sixth compartment 647 to reduce the manufacturing cost of embodiment 620. It should be noted that the first compartment 621 operates in a different manner than the sixth compartment 647. The downstream IMSA 652 is configured to accelerate the flow. Therefore, the downstream IMSA 652 applies a thrust to embodiment 620 directed in the opposite direction of the fluid flow relative to embodiment 620, as shown by thrust vector 656.

[0315] IFMA configuration 620 may include an intermediate IMSA, similar to embodiment 560. In IFMA configuration 620, the intermediate IMSA is implemented by two cars (i.e., third car 633 and fourth car 634) instead of one car. Both cars are identical to the sixth car 647 or the first car 621 to reduce the manufacturing cost of embodiment 620. In this embodiment, the ducted fan 634 of the third car 633 is feathered. The ducted fan 640 of the fourth car 634 is... Figure 20 The intermediate IMSA 580 is configured in a similar manner. Therefore, the IMSA 640 applies a thrust to embodiment 620 in the direction of fluid flow relative to embodiment 620, as shown by thrust vector 644.

[0316] Upstream IMSA can reduce the drag of IFMA configuration 560 or 620. This drag reduction can include a reduction in the viscous drag of the carriage. The drag reduction is associated with altering the spatial distribution of fluid velocity relative to and near IFMA configuration 560 or 620 through upstream IMSA. This alteration can refer to reducing the average magnitude of the spatial velocity gradient of the fluid flow. For example, the configurations of upstream and downstream IMSA can be mathematically optimized to minimize the total power consumption of IFMA configuration 560 or 620 constrained by constraints such as structural or economic limitations.

[0317] Figure 22 This is a cross-sectional view of an exemplary embodiment 1001 including an engine 1002.

[0318] Engine 1002 can be the core of a turboshaft engine, or a turbofan or scroll engine. As a turboshaft engine, engine 1002 can be used to provide power, for example, to helicopters or power plants.

[0319] Engine 1002 includes a passage 1015 having an inlet 1014 and an outlet 1027. Engine 1002 includes an axial compressor 1016 having multiple stages, wherein each stage includes a rotor disk such as a rotor disk 1018 and a stator disk such as a stator disk 1017. Engine 1002 also includes a combustion chamber 1019 and a turbine 1020. Turbine 1020 is configured to drive compressor 1016 via shaft 1025. In other embodiments, engine 1002 may include two or three separate spools. In some embodiments, engine 1002 may also include a gearbox. Engine 1002 includes a housing 1024 having an outer surface 1028, which in this embodiment is cylindrical. The configuration of engine 1002 is similar to the core of a conventional jet engine, such as a turbofan engine, turbojet engine, turboshaft engine, or turboprop engine.

[0320] Exemplary embodiment 1001 also includes a first thrust device 1003 and a second thrust device 1029. In this particular embodiment, the first thrust device 1003 includes a first propeller 1004 and a second propeller 1007, the first propeller 1004 having several propeller blades, such as blades 1005 and 1006, and the second propeller 1007 having several propeller blades, such as blade 1009. The upstream thrust device 1003 or the first thrust device 1003 is configured to accelerate fluid and introduce fluid into the inlet 1014 of the engine 1002, as shown in flow pipes 1013 and 1012.

[0321] In this particular embodiment, the second thrust device 1029 further includes a first propeller 1030 and a second propeller 1033. In other embodiments, the first thrust device 1003 and the second thrust device 1029 may each include a single propeller. In other embodiments, the first thrust device 1003 and the second thrust device 1029 may each include multiple propellers. The downstream thrust device 1029 or the first thrust device 1029 is configured to slow down fluid flowing from the outlet 1027 of the passage 1015 of the engine 1002, as shown in flow pipes 1038 and 1039.

[0322] In this particular embodiment, the first thrust device 1003 is rigidly connected to the second thrust device 1029 via a drive shaft 1011. Figure 22In this configuration, a rigid drive shaft 1011 rigidly connects the first propeller 1004 and the second propeller 1009 of the first propulsion device 1003, and the first propeller 1030 and the second propeller 1033 of the second propulsion device 1029. In some embodiments, such as Figure 22 In the illustrated embodiment 1001, all the work done by the first thrust device 1003 is provided by the work extracted from the fluid by the second thrust device 1029.

[0323] In other embodiments, only a portion of the work done by the first thrust device 1003 on the fluid is provided by the work extracted from the fluid by the second thrust device 1029. In such embodiments, the remaining work done by the first thrust device 1003 may be provided by an engine, such as engine 1002, or by an electric motor, or by different actuators or engines. In other embodiments, only a portion of the work recovered by the second thrust device 1029 is delivered to the first thrust device 1003. In such embodiments, excess work may be transferred to a generator, such as a generator, or to the drive shaft of a turboshaft engine, for example.

[0324] In other embodiments, the second thrust device 1029 may be mechanically coupled to the first thrust device 1003 via a drivetrain, which may include gears, clutches, gearboxes, or other linkages and mechanisms. The drivetrain may also include several spools or shafts that mechanically connect the propeller of the second thrust device 1029 to the propeller of the first thrust device 1003. For example, in a dual-shaft arrangement, the first propeller 1030 of the second thrust device 1029 may be configured to mechanically drive the second propeller 1007 of the first thrust device 1003 via a first drive shaft, and the second propeller 1033 of the second thrust device 1029 may be configured to mechanically drive the first propeller 1004 of the first thrust device 1003 via a second drive shaft. This allows each drive shaft to operate at a different speed. In some such embodiments, the first and second drive shafts rotate in opposite directions in a coaxial counter-rotating arrangement.

[0325] In other embodiments, the second thrust device 1029 may be electrically connected to the first thrust device 1003. For example, the second thrust device 1029 may be configured to drive a generator. A portion of the electricity generated by the generator may be supplied to an electric motor driving the first thrust device 1003. Another portion of the electricity generated by the generator may be supplied to a different electric motor, to the power grid, or to an energy storage device, such as a battery, capacitor, or inductor. In some embodiments, each propeller may be connected to a separate electric motor. Each of the first propeller 1004 and the second propeller 1007 of the first propeller 1003 may be driven by a separate electric motor, and each of the first propeller 1030 and the second propeller 1033 may drive a separate generator. This allows each individual rotor to rotate at a different speed and allows for optimization of the performance of each propeller, provided that constraints on the net torque of the device 1001 or the attached vehicle are met.

[0326] The thrust provided by the first thrust device 1003, i.e., the thrust of both the first propeller 1004 and the second propeller 1007, is directed towards the left side of the page in the negative X direction. The thrust provided by the second thrust device 1029, i.e., the thrust of both the first propeller 1030 and the second propeller 1033, is directed towards the right side of the page in the positive X direction. Therefore, part or all of the thrust generated by the first thrust device 1003 is offset by the negative thrust or drag generated by the second thrust device 1029.

[0327] The advantage of the first thrust device 1003 is that the mass flow rate of the air entering the core of the engine 1002 increases as the fluid is accelerated into the first opening 1014 of the engine 1002 by the first thrust device 1003. Any excess thrust generated by the accelerated fluid by the first thrust device 1003 can be offset by the second thrust device 1029, which operates as a turbine. This allows the core of the engine 1002 to operate at a greater local free-flow velocity. The increased mass flow rate of the fluid through the core of the engine 1002 of a given size can reduce the induced power of the engine 1002 and thus increase the fuel efficiency of the engine 1002. This increase in efficiency due to the increased local free-flow velocity can be particularly significant during operation at low free-flow velocities, such as during takeoff or during stationary operation in a power plant.

[0328] Figure 22 The configuration in is similar to Figure 4 The configuration shown has the thrust device 29 replaced by the core of engine 1002. Figure 22 The configuration in is similar to Figure 8 The configuration shown has the fluid interaction device 162 replaced by the core of the engine 1002.

[0329] Figure 23 This is a cross-sectional view of an exemplary embodiment 1060 employing a ducted fan.

[0330] Example 1060 includes a conduit 1061 having an inlet 1064 connected to an outlet 1065 via a channel 1066. In this particular embodiment, the outer surface 1062 is cylindrical. In other embodiments, the outer surface 1062 may be in the shape of a conical cylinder or the shape of a conventional conduit for a conventional duct fan.

[0331] In this embodiment, the first thrust device 1073 includes a propeller 1073 having several blades, such as blade 1074 or blade 1075. In this embodiment, the second thrust device 1076 includes a propeller 1076 having several blades, such as blade 1078. The first propeller 1073 and the second propeller 1076 rotate about an axis 1079 and are rigidly connected by a shaft 1071.

[0332] In other embodiments, the first propeller 1073 and the second propeller 1076 may be mechanically coupled via a transmission system, which may include, for example, gears, clutches, linkages, or gearboxes. In other embodiments, the first propeller 1073 and the second propeller 1076 may be electrically coupled. The second propeller 1076 may drive a generator, which may be configured to deliver power to, for example, an electric motor that drives the first propeller 1073. The electrical coupling may also include an energy storage device, such as a battery, capacitor, or inductor.

[0333] The flow tube 1069 is incident on the leading edge 1067 of the pipe 1061, and the flow tube 1070 originates from the trailing edge 1068 of the pipe 1061. The thrust provided by the first thrust device 1073 is in the negative X direction, toward the left side of the page. The thrust provided by the second thrust device 1076 is in the positive X direction, toward the right side of the page. The X-axis is parallel to the bottom of the page or the long side of the page. Therefore, part or all of the thrust generated by the first thrust device 1073 is offset by the negative thrust or drag generated by the second thrust device 1076.

[0334] In some embodiments, the blade pitch of the first propeller 1073 or the second propeller 1076 can be changed and adjusted. The rotational speed of the first propeller 1073 or the second propeller 1076 can also be changed and controlled. In this way, the magnitude of the thrust or drag generated by the first propeller 1073 or the second propeller 1076 can be changed for different flight modes or operating conditions.

[0335] The thrust of the first propeller 1073 can exceed the net thrust required by the device 1060 under nominal operating conditions. For example, the thrust of the first propeller 1073 can exceed the net thrust required by the device 1060 by 10 times during nominal operating conditions. The excessive thrust generated by the first propeller 1073 can be offset or eliminated during nominal operation by the negative thrust or drag generated by the second propeller 1078. In this way, the mass flow rate of the fluid flowing through the channel 1066 can be artificially increased, which can reduce the resulting drag under nominal operating conditions with a given net thrust.

[0336] Figure 23 The configuration in is similar to Figure 3 The configuration shown includes thrusters 20 and 21, which include duct fans, with the ducts connected to form a single duct.

[0337] Figure 24 This is a cross-sectional view of an embodiment including an engine 1100, which may include a turbine shaft or a turboprop.

[0338] Engine 1100 includes a first thrust device 1101, which may include a first propeller 1101, the first propeller 1101 including several propeller blades, such as propeller blade 1103 or propeller blade 1104. Engine 1100 also includes a second thrust device 1122, the second thrust device 1122 including a second propeller 1122.

[0339] Engine 1100 includes an engine core, which in turn includes a compressor 1109. The compressor 1109 may include several stages, such as a rotor disk (e.g., rotor disk 1111) and a stator disk (e.g., stator disk 1110). The engine core also includes a combustion chamber 1112 in an annular channel 1108. The engine core also includes a turbine 1113, which drives the compressor 1109 via a shaft 1118. The engine core is surrounded by a housing 1117, which in this case has a cylindrical outer surface 1121. A first thrust device, a second thrust device, the compressor, and the turbine rotor disk rotate about axis 1129.

[0340] The second thrust device 1122 includes a hot section 1127 located in the exhaust section of the engine core, and this hot section 1127, together with the cold section 1128 of the second thrust device 1122 located in the flow pipe 1106 of the first thrust device 1101, transmits power to the central shaft 1105. In other embodiments, the central shaft 1105 is also driven by a separate turbine rotor disk located within the turbine 1113. In other embodiments, the central shaft 1105 is further driven by two or more separate turbine rotor disks located within the turbine 1113.

[0341] exist Figure 24 In this configuration, the second thrust device 1122 is mechanically connected to the first thrust device 1101 via a drive shaft 1105. Therefore, the power extracted from the fluid by the second thrust device 1122 is transmitted to the first thrust device 1101 via the drive shaft 1105.

[0342] In other embodiments, the second thrust device 1122 may be mechanically coupled to the first thrust device 1101 via a transmission system, which may include gears, clutches, gearboxes, or other linkages and mechanisms. The transmission system may also include several spools or shafts that mechanically connect the propeller of the second thrust device 1122 to the propeller of the first thrust device 1101.

[0343] In other embodiments, the second thrust device 1122 may be electrically connected to the first thrust device 1101. For example, the second thrust device 1122 may be configured to drive a generator. A portion of the electricity generated by the generator may be supplied to an electric motor driving the first thrust device 1101. Another portion of the electricity generated by the generator may be supplied to a different electric motor, to the power grid, or to an energy storage device, such as a battery, capacitor, or inductor. In some embodiments, each propeller may be connected to a separate electric motor. This allows each individual rotor to rotate at a different speed and allows for optimization of the performance of each propeller, provided that constraints on the net torque of the device 1100 or the attached vehicle are met.

[0344] In other embodiments, the engine core need not be a single spool arrangement, but may include, for example, two or three spools. For instance, the engine core may include a low-pressure turbine mechanically coupled to a low-pressure compressor via a first drive shaft. The engine core may also include a high-pressure turbine mechanically coupled to a high-pressure compressor via a second drive shaft.

[0345] The first thrust device 1101 exerts its thrust in the negative X direction toward the left side of the page. The second thrust device 1122 exerts its thrust in the positive X direction toward the right side of the page. The X-axis is parallel to the bottom of the page or the long side of the page.

[0346] The thrust of the first propeller 1101 can exceed the net thrust required by the device 1100 under nominal operating conditions. For example, the thrust of the first propeller 1101 can exceed the net thrust required by the device 1100 by 10 times during nominal operating conditions. The excess thrust generated by the first propeller 1101 can be offset or eliminated by the negative thrust or drag generated by the second propeller 1122 during nominal operation. In this way, the mass flow rate of the fluid flowing through the flow tube 1106 can be artificially increased, which can reduce induced drag under nominal operating conditions with a given net thrust.

[0347] Figure 23 The configuration in is similar to Figure 3 The configuration shown in the figure is in which the thrust device 20 is powered by the core of a turbine shaft or turboprop engine, and in which the thrust device 20 is rigidly connected to the thrust device 21 via a central drive shaft 1105.

[0348] Figure 25 This is a cross-sectional view of an exemplary embodiment including a ducted turbofan engine 1150.

[0349] Engine 1150 includes a first thrust device 1151, which may include a first propeller 1151, the first propeller 1151 including several propeller blades, such as propeller blade 1153 or propeller blade 1154. Engine 1150 also includes a second thrust device 1172, which may include a second propeller 1172.

[0350] Engine 1150 includes an engine core, which in turn includes a compressor 1159, which may include several stages having rotor discs and stator discs. The engine core also includes a combustion chamber 1162 in an annular channel 1158. The engine core also includes a turbine 1163, which drives the compressor 1159 via a shaft 1168. The engine core is surrounded by a housing 1167, which in this case has a cylindrical outer surface. A first thrust device, a second thrust device, and the compressor and turbine rotor discs rotate about an axis 1179.

[0351] The engine 1150 also includes a conduit 1180 having a first opening 1181 and a second opening 1182. A flow tube 1156 is incident on the leading edge 1183 of the conduit, and a flow tube 1190 originates from the trailing edge 1184 of the conduit. The conduit includes an annular channel 1185 that includes fluid bypassing the engine core 1158. In this particular embodiment, the outer surface 1189 of the conduit is cylindrical.

[0352] The second thrust device 1172 includes a hot section 1177 located in the exhaust section of the engine core, and this hot section 1177, together with the cold section 1178 of the second thrust device 1172 located in the flow tube of the first thrust device 1151, transmits power to the central shaft 1155. In other embodiments, the central shaft 1155 is also driven by a separate turbine rotor disk located within the turbine 1163. In other embodiments, the central shaft 1155 is further driven by two or more separate turbine rotor disks located within the turbine 1163.

[0353] exist Figure 24In this configuration, the second thrust device 1172 is mechanically connected to the first thrust device 1151 via a drive shaft 1155. Therefore, the power extracted from the fluid by the second thrust device 1172 is transmitted to the first thrust device 1151 via the drive shaft 1155.

[0354] In other embodiments, the second thrust device 1172 may be mechanically coupled to the first thrust device 1151 via a transmission system, which may include gears, clutches, gearboxes, or other linkages and mechanisms. The transmission system may also include several spools or shafts that mechanically connect the propeller of the second thrust device 1172 to the propeller of the first thrust device 1151.

[0355] In other embodiments, the second thrust device 1172 may be electrically connected to the first thrust device 1151. For example, the second thrust device 1172 may be configured to drive a generator. A portion of the electricity generated by the generator may be supplied to an electric motor driving the first thrust device 1151. Another portion of the electricity generated by the generator may be supplied to a different electric motor, to the power grid, or to an energy storage device, such as a battery, capacitor, or inductor. In some embodiments, each propeller may be connected to a separate electric motor. This allows each individual rotor to rotate at a different speed and allows for optimization of the performance of each propeller, provided that constraints on the net torque of the device 1150 or the attached vehicle are met.

[0356] In other embodiments, the engine core need not be a single spool arrangement, but may include, for example, two or three spools. For instance, the engine core may include a low-pressure turbine mechanically coupled to a low-pressure compressor via a first drive shaft. The engine core may also include a high-pressure turbine mechanically coupled to a high-pressure compressor via a second drive shaft.

[0357] The first thrust device 1151 exerts its thrust in the negative X direction toward the left side of the page. The second thrust device 1172 exerts its thrust in the positive X direction toward the right side of the page. The X-axis is parallel to the bottom of the page or the long side of the page.

[0358] The thrust of the first propeller 1151 can exceed the net thrust required by the device 1150 under nominal operating conditions. For example, the thrust of the first propeller 1151 can exceed the net thrust required by the device 1150 by 10 times during nominal operating conditions. The excess thrust generated by the first propeller 1151 can be offset or eliminated by the negative thrust or drag generated by the second propeller 1172 during nominal operation. In this way, the mass flow rate of the fluid flowing through the flow pipe 1156 can be artificially increased, which can reduce induced drag under nominal operating conditions with a given net thrust. The conduit 1180 is used to further increase the mass flow rate of the fluid through the first thrust device 1151.

[0359] The increased mass flow rate is particularly useful for operating conditions with low free-flow velocities, such as during takeoff, climb, or descent, or during operation as a turboshaft engine in a power plant. Typically, the effect of the increased mass flow rate is particularly useful at free-flow velocities around or below Mach 0.4. At high free-flow velocities, the mass flow rate is typically limited by the requirement that the speed of the fan blades, such as the blades of the first thrust device 1151, does not significantly exceed the speed of sound. In such mass flow rate-limited cases, in some embodiments, the second thrust device 1172 may be feathered. During feathering, the magnitude of the thrust generated by the second thrust device 1172 is negligible, and the effect of the second thrust device 1172 on the flow is negligible. In other words, the engine 1150 can operate as a conventional single-fan turbofan engine at high free-flow velocities, such as at or near Mach 0.9. In this case, the fan of the single turbofan is the first thrust device 1151, where the feathered second thrust device 1172 plays a negligible role.

[0360] Figure 25 The configuration in is similar to Figure 24 The configuration shown is in which engine 1100 is enclosed by a pipe. Figure 25 The configuration in is similar to Figure 23 The configuration shown in the diagram is in which the first thrust unit 1073 is powered by the core of a turbofan engine.

[0361] Figure 26 This is a cross-sectional view of embodiment 1200, which includes a ramjet engine 1201.

[0362] The ramjet engine 1201 may include a first opening 1206 connected to a second opening 1212 via a channel 1205. The ramjet engine 1201 includes a first contraction 1207, a first throat, a first expansion 1208, a flame stabilizer and fuel injector 1209, a second contraction 1210, a second throat, and a second expansion 1211. The channel 1205 is enclosed by a body material 1202. In this embodiment, the outer surface 1203 of the ramjet engine 1201 is cylindrical.

[0363] As is typical in a conventional ramjet engine, fluid enters the first opening 1206 at supersonic speed. The fluid is then compressed and decelerated within the first contraction 1207. At the first throat, the fluid travels at approximately Mach 1 relative to the ramjet engine 1201. Downstream of the first throat and through the first expansion 1208, the fluid decelerates and is further compressed to subsonic speed. In a practical embodiment, a shock wave is stabilized within the first expansion 1208, with the flow upstream of the shock wave being supersonic and the flow downstream being subsonic. Downstream of the flame stabilizer 1209, the injected fuel burns and the fluid is heated. In the entire converging-diverging conduit formed by the second contraction 1210 and the second expansion 1211, the fluid is again accelerated to supersonic speed and exits through the second opening 1212.

[0364] Within the ramjet engine 1201, and upstream and downstream of the ramjet engine 1201, there are volume force generating devices of BFGA 1213. In this particular embodiment, BFGA 1213 includes a collection of positive charges 1216 enclosed within an elongated and electrically insulating structure at the symmetry axis of the ramjet engine 1201. The collection of positive charges 1216 is structurally supported by several support rods, such as support rods 1214.

[0365] The BFGA is configured to generate a volume force per unit mass acting on each element of the fluid, such as the individual molecules of the fluid. For example, the fluid could be air. The volume force per unit mass is configured to act in a radially inward direction, toward the axis of symmetry of the cylindrical ramjet engine 1201, toward the BFGA 1213, i.e., toward the collection of positively charged portions 1216, as indicated by the thick arrow, such as arrow 1217.

[0366] The function of BFGA 1213 is to attract and compress the fluid in its vicinity, as shown in flow tubes 1219 and 1220. In this way, the mass flow rate through ramjet nozzle 1201 can be artificially increased. This increase in mass flow rate can reduce the induced power and increase the efficiency of a ramjet engine 1201 of a given size.

[0367] The role of BFGA 1213 is to polarize the air molecules near BFGA 1213 and to attract the air molecules to the region of strong electric field strength and associated charge concentration 1216 near BFGA 1213.

[0368] In other embodiments, the body material 1202 of the ramjet engine 1201 casing may further include a collection of electrically insulating negative charges arranged in a cylindrical or annular manner along the length of the casing. The air within the passage can then be considered as the dielectric in a cylindrical capacitor. This can increase the electric field strength within the passage 1205 of the ramjet engine 1201 and increase the volume force per unit mass near the BFGA 1213. In other embodiments, the polarity of the charges may be opposite, with the charge collection 1216 comprising negative charges and the charge collection within the body material 1202 comprising positive charges.

[0369] A collection of charges can be generated by embedding ions or electrons within an electrically insulating material. A collection of charges can also be generated by connecting two electrical conductors to the two terminals of a voltage source such as a battery or generator. As described above, the air near a BFGA can be considered as the dielectric between two opposing charging plates of a capacitor, or as the dielectric near a single charging plate.

[0370] In other embodiments, the volume forces can also be magnetic in nature. For example, the fluid may include magnetic dipoles, and the BFGA can be configured to generate a magnetic field that is further configured to generate a volume force per unit mass on the respective magnetic dipoles within the fluid.

[0371] Unless otherwise specified or explicit in the context, the term "or" is equivalent to "and / or" herein. The embodiments and methods described herein are intended only to illustrate and demonstrate the principles of the embodiments disclosed herein. Embodiments may be performed in several different ways not shown, and are therefore not limited to the instances, arrangements, configurations, or methods of operation described herein or depicted in the accompanying drawings. Based on the teachings provided herein, those skilled in the art will now be able to devise many alternative instances, embodiments, arrangements, configurations, or methods of operation not explicitly shown or described.

Claims

1. An intentional fluid manipulation device (IFMA) assembly, the intentional fluid manipulation device comprising: An upstream intentional momentum release device (IMSA) is configured to apply a first induced velocity to the local free-flow during nominal operating requirements; as well as A downstream intentional momentum release device is arranged such that during the nominal operating requirement, fluid flow through at least a portion of both the upstream and downstream intentional momentum release devices forms a flow tube, the downstream intentional momentum release device being configured to apply a second induced velocity to a localized free-flow within the flow tube, wherein the second induced velocity at the location of the downstream intentional momentum release device has a component in the opposite direction to the first induced velocity at the location of the downstream intentional momentum release device; and The upstream intentional momentum release device can be configured to transfer more power to the fluid in the flow tube than the power removed from the fluid in the flow tube by the downstream intentional momentum release device during a first nominal operating requirement, wherein the first nominal operating requirement includes transferring net power to the fluid in the flow tube, or The upstream intentional momentum release device can be configured to transfer less power to the fluid in the flow tube than the power removed from the fluid in the flow tube by the downstream intentional momentum release device during a second nominal operating requirement, wherein the second nominal operating requirement includes the removal of net power from the fluid in the flow tube. The upstream intentional momentum release device and the downstream intentional momentum release device are surrounded by the same pipe.

2. The intentional fluid manipulation device assembly according to claim 1, further comprising: An intermediate intentional momentum release device is located upstream of the downstream intentional momentum release device and downstream of the upstream intentional momentum release device, at least a portion of the intermediate intentional momentum release device is located within a portion of the flow tube, and the intermediate intentional momentum release device is configured to apply a third induced velocity to the local free flow within at least a portion of the flow tube.

3. The intentional fluid manipulation device assembly according to claim 1, wherein, The first nominal operating requirement or the second nominal operating requirement includes generating a net thrust within the flow tube, wherein the net thrust is equal to the first thrust vector of the upstream intentional momentum release device plus the second thrust vector of the downstream intentional momentum release device, wherein the magnitude of the first thrust vector can be greater than or less than the magnitude of the second thrust vector.

4. The intentional fluid manipulation device assembly according to claim 1, wherein, Compared to the scenario where the effect of the downstream intentional momentum release device on fluid flow is negligible, the net induced power of the fluid transmitted to the flow tube by the intentional fluid manipulation device assembly is reduced during the first nominal operating requirement and during the period of generating a given net thrust within the flow tube. Where the effect of the upstream intentional momentum release device on fluid flow is negligible, the net induced power removed by the intentional fluid manipulation device assembly from the fluid in the flow tube during the second nominal operating requirement and during the generation of a given net thrust in the flow tube is increased in magnitude.

5. The intentional fluid manipulation device assembly according to claim 1, wherein, The upstream intentional momentum release device or the downstream intentional momentum release device includes an open rotor, a duct rotor, or a translating or rotating wing or foil.

6. The intentional fluid manipulation device assembly according to claim 5, wherein, The pitch angle of the rotor blades relative to the rotor hub of the propeller can be changed.

7. The intentional fluid manipulation device assembly according to claim 1, wherein, The first induced velocity or the second induced velocity has a non-zero component perpendicular to the local free flow at the upstream intentional momentum release device or the downstream intentional momentum release device, respectively.

8. The intentional fluid manipulation device assembly according to claim 1, wherein, The first induced velocity or the second induced velocity has a non-zero component parallel to the local free flow at the upstream intentional momentum release device or the downstream intentional momentum release device, respectively.

9. The intentional fluid manipulation device assembly according to claim 8, wherein, The first induced velocity has a non-zero component in the direction opposite to the direction of the local free flow at the upstream intentional momentum release device.

10. The intentional fluid manipulation device assembly according to claim 8, wherein, The first induced velocity has a non-zero component in the same direction as the local free flow direction at the upstream intentional momentum release device.

11. The intentional fluid manipulation device assembly according to claim 1, wherein, Power is transferred between the upstream intentional momentum release device and the downstream intentional momentum release device via a power transfer device.

12. The intentional fluid manipulation device assembly according to claim 11, wherein, The power is transmitted mechanically.

13. The intentional fluid manipulation device assembly according to claim 12, wherein, The power transmission device includes a drive shaft, a gear system, and / or a clutch.

14. The intentional fluid manipulation device assembly according to claim 11, wherein, The power is electrically transmitted.

15. The intentional fluid manipulation device assembly according to claim 14, wherein, The downstream intentional momentum release device drives a generator, and the power from the generator is transmitted to a motor connected to the upstream intentional momentum release device; or the upstream intentional momentum release device drives a generator, and the power from the generator is transmitted to a motor connected to the downstream intentional momentum release device.

16. The intentional fluid manipulation device assembly of claim 11, wherein, Power is transferred from the downstream intentional momentum release device to the upstream intentional momentum release device.

17. The intentional fluid manipulation device assembly according to claim 1, wherein, Compared to the case where the effect of the downstream intentional momentum release device on fluid flow is negligible, for a given net thrust, changing the mass flow rate of the fluid in the flow tube, wherein the change is to increase the mass flow rate.

18. The intentional fluid manipulation device assembly according to claim 2, wherein, The third induced velocity has a non-zero component perpendicular to the local free flow within the flow tube at the intermediate intentional momentum release device.

19. The intentional fluid manipulation device assembly according to claim 2, wherein, The third induced velocity has a non-zero component within the flow tube at the intermediate intentional momentum release device, which is parallel to the local free flow.

20. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device can be configured to transfer power to the fluid.

21. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device can be configured to remove power from the fluid.

22. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device is configured to transfer power to the upstream intentional momentum release device and / or the downstream intentional momentum release device.

23. The intentional fluid manipulation device assembly according to claim 22, wherein, Power is mechanically transferred between the intermediate intentional momentum release device and the upstream intentional momentum release device and / or the downstream intentional momentum release device.

24. The intentional fluid manipulation device assembly according to claim 22, wherein, Power is electrically transferred between the intermediate intentional momentum release device and the upstream intentional momentum release device and / or the downstream intentional momentum release device, wherein the intermediate intentional momentum release device drives a generator or is driven by an electric motor, and wherein power is transferred to the electric motor connected to the upstream intentional momentum release device and / or the downstream intentional momentum release device, or from the generator connected to the upstream intentional momentum release device and / or the downstream intentional momentum release device.

25. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device includes a propeller with an open rotor or conduit configuration.

26. The intentional fluid manipulation device assembly according to claim 25, wherein, The pitch angle of the rotor blades relative to the rotor hub of the propeller can be changed.

27. The intentional fluid manipulation device assembly according to claim 2, wherein, The upstream intentional momentum release device, the intermediate intentional momentum release device, and the downstream intentional momentum release device are surrounded by the same pipe.

28. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device includes a wing or a foil.

29. The intentional fluid manipulation device assembly according to claim 2, wherein, The intermediate intentional momentum release device includes at least a portion of a jet engine, wherein the jet engine assembly includes a turboprop engine, a turbofan jet engine, a turbojet engine, or a ramjet engine.

30. The intentional fluid manipulation device assembly according to claim 29, wherein, The intermediate intentional momentum release device includes the core of a jet engine.

31. The intentional fluid manipulation device assembly according to claim 30, wherein, A portion of the flow tube flows over the core of the jet engine, while the remainder of the flow tube forms a bypass around the core of the jet engine.

32. The intentional fluid manipulation device assembly according to claim 31, wherein, The upstream intentional momentum release device includes a rotor, wherein the upstream intentional momentum release device is at least partially powered by the core of the jet engine, wherein a portion of the flow tube flows through the core of the jet engine, and the remaining portion of the flow tube forms a bypass around the core of the jet engine, wherein the core of the jet engine is located upstream and downstream of the downstream intentional momentum release device, and the downstream intentional momentum release device includes a rotor, and wherein the upstream intentional momentum release device, the core of the jet engine, and the downstream intentional momentum release device are surrounded by the same duct in the turbofan assembly.

33. The intentional fluid manipulation device assembly according to claim 29, wherein, The upstream intentional momentum release device includes an open rotor, and the downstream intentional momentum release device includes an open rotor.

34. The intentional fluid manipulation device assembly according to claim 29, wherein, At least a portion of the power of the jet engine is transferred to the upstream intentional momentum release device and / or the downstream intentional momentum release device.

35. The intentional fluid manipulation device assembly according to claim 29, wherein, Compared to the case where the effect of the downstream intentional momentum release device on fluid flow is negligible, for a given net thrust, the upstream and downstream intentional momentum release devices are configured to increase the mass flow rate of the fluid passing through the jet engine during nominal operation.

36. The intentional fluid manipulation device assembly according to claim 2, wherein, The third induced velocity at the location of the intermediate intentional momentum release device has a component in the opposite direction to the first induced velocity at the location of the intermediate intentional momentum release device.

37. The intentional fluid manipulation device assembly according to claim 2, wherein, The third induced velocity at the location of the intermediate intentional momentum release device has a component in the same direction as the first induced velocity at the location of the intermediate intentional momentum release device.

38. The intentional fluid manipulation device assembly according to claim 32, wherein, The core of the jet engine is a turboshaft engine and / or a turbojet engine.

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