Nacelle unit, distributed propulsion nacelle and new energy aircraft

Abstract

The invention relates to a short cabin unit, a distributed propulsion short cabin and a new energy aircraft. The short cabin unit comprises an air inlet section, an exhaust section and a ducted fan. The ducted fan is arranged between the air inlet section and the exhaust section; the air inlet section is a non-rotary body, and the air exhaust section is a rotary body; the nacelle is designed in a sinking mode, and the sinking mode is achieved in the mode that the distance between a rotating shaft of a ducted fan and a lower lip opening of an air inlet section in the longitudinal direction is smaller than the radius of the ducted fan. And a diffusion section is formed below the air inlet section. According to the nacelle design, the windward area of the nacelle is properly reduced, so that the design flow of the nacelle is matched with the flow of the surface above a wing under the cruise working condition, the adverse effect of a front high-pressure area caused by overflow of the nacelle on the wing is weakened, meanwhile, the differential pressure resistance in front of and behind the nacelle is weakened, and pneumatic matching is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of nacelle design, and in particular relates to a nacelle unit, a distributed propulsion nacelle and a new energy aircraft. Background Art

[0002] As the public pays more and more attention to environmental protection, society has put forward green development requirements for the rapidly growing aviation industry. The rapid progress of new energy underlying technologies has made medium and large new energy manned aircraft driven by electricity (i.e. electric propulsion) possible.

[0003] Unlike traditional aircraft engines that first convert chemical energy into internal energy and then use internal energy to generate thrust, electric propulsion power units directly use input electrical energy to generate thrust. This simplified thrust generation method makes the electric propulsion power unit subject to fewer design constraints and can be more flexible in power layout. One of the efficient propulsion layout forms is distributed propulsion. Distributed propulsion is a relatively new power layout method proposed in the field of aircraft design. This layout uses an array of multiple smaller ducted fans, which are arranged close to the wing (or fuselage) and use boundary layer suction to improve propulsion efficiency.

[0004] Since the ducted fan is arranged close to the wing, the distributed nacelle that provides intake and exhaust for the ducted fan forms a strong aerodynamic coupling with the wing. In order to ensure that the whole aircraft has excellent aerodynamic performance under various flight conditions, it is necessary to optimize the aerodynamic design of the distributed nacelle surrounding the engine array. If the nacelle is simply obtained using the traditional design method and arranged on the wing, the free flow far in front of the cruise state will be decelerated and pressurized to form a low-speed and high-pressure airflow before the distributed nacelle intake, and this airflow will destroy the high-speed and low-pressure flow field state on the wing surface, and the impact is specifically manifested as reduced wing lift and increased drag, which seriously damages the aerodynamic performance of the whole aircraft. On the other hand, maintainability needs to be considered in the actual use of the aircraft, especially in the scenario of medium and large aircraft. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a nacelle unit, a distributed propulsion nacelle and a new energy aircraft, which are used to overcome the current defects.

[0006] A nacelle unit is used for a new energy aircraft, the nacelle unit comprising: an air intake section, an exhaust section and a ducted fan;

[0007] The ducted fan is arranged between the air intake section and the exhaust section;

[0008] The air intake section is a non-rotating body, and the exhaust section is a rotating body;

[0009] The nacelle adopts a sinking type, and the sinking type is achieved by a method in which the distance between the rotating shaft of the ducted fan and the lower lip of the air intake section in the longitudinal direction is smaller than the radius of the ducted fan;

[0010] A diffuser section is formed below the air intake section.

[0011] According to the aspects described above and any possible implementation method, an implementation method is further provided, wherein the ducted fan includes a rotor, a stator, a fan casing and a motor, wherein the rotor is connected to the shaft of the motor; one end of the stator is connected to the fan casing, and the other end is connected to the casing of the motor.

[0012] According to the aspects and any possible implementations described above, an implementation is further provided, which also includes a tail cone connected to the motor, which forms a jet surface together with the exhaust section to generate maximum thrust.

[0013] The present invention also provides a distributed propulsion nacelle, which includes a plurality of detachable nacelle units arranged in parallel.

[0014] According to the aspects described above and any possible implementation, there is further provided an implementation, where each distributed propulsion nacelle includes 2 to 8 nacelle units.

[0015] According to the aspects described above and any possible implementation, an implementation is further provided, wherein each of the distributed propulsion nacelles also includes an exhaust after-straightening part, each of the nacelle units includes a circular cross-section formed by an exhaust section, and the exhaust after-straightening part is arranged in a triangular area between each circular cross-section.

[0016] The present invention also provides a new energy aircraft, which includes a fuselage, wings and the distributed propulsion nacelles, wherein the wings are arranged on the left and right sides of the fuselage, and the distributed propulsion nacelles are arranged on the wings.

[0017] According to the aspects described above and any possible implementation, an implementation is further provided, wherein there are two sets of distributed propulsion nacelles, each set is arranged on a wing close to the fuselage.

[0018] According to the aspects and any possible implementations described above, an implementation is further provided, wherein each set of the distributed propulsion nacelles adopts a modular design, that is, it is composed of an innermost nacelle unit and an outermost nacelle unit arranged and combined along the wing span.

[0019] According to the above aspects and any possible implementations, an implementation is further provided, in which the innermost nacelle unit and the outermost nacelle unit have different outer shapes.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] A nacelle unit of the present invention is used for a new energy aircraft, and the nacelle unit includes: an air intake section, an exhaust section and a ducted fan; the ducted fan is arranged between the air intake section and the exhaust section; the air intake section is a non-rotating body, and the exhaust section is a rotating body; the nacelle adopts a sinking type, and the sinking type is achieved by the distance between the rotating shaft of the ducted fan and the lower lip of the air intake section in the longitudinal direction being less than the radius of the ducted fan; a diffuser section is formed below the air intake section. The sinking design of the nacelle of the present invention appropriately reduces the windward area of ​​the nacelle, so that the design flow of the nacelle matches the surface flow above the wing under the cruising condition, reduces the adverse effect of the front high pressure area caused by the overflow of the nacelle on the wing, and at the same time reduces the pressure difference resistance before and after the nacelle, so as to achieve aerodynamic matching. In terms of configuration, the distributed nacelle is designed so that each unit can be disassembled independently, which is convenient for ground staff to carry out targeted maintenance and inspection of the distributed power aircraft, shortens the maintenance time, and improves the economy. The present invention can be used for new energy aircraft using distributed electric propulsion, and can provide high-quality intake and exhaust functions for distributed power devices at a lower drag cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the installation of the distributed nacelle of the present invention;

[0023] Figure 2 It is a cross-sectional view of the distributed nacelle of the present invention in the installed state. DETAILED DESCRIPTION

[0024] In order to better understand the technical solution of the present invention, the content of the present invention includes but is not limited to the specific implementation methods described below, and similar technologies and methods should be considered to be within the scope of protection of the present invention. In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] It should be clear that the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a nacelle unit for a new energy aircraft, the nacelle unit comprising: an air intake section, an exhaust section and a ducted fan;

[0027] The ducted fan is arranged between the air intake section and the exhaust section;

[0028] The air intake section is a non-rotating body, and the exhaust section is a rotating body;

[0029] The nacelle adopts a sinking type, and the sinking type is achieved by a method in which the distance between the rotating shaft of the ducted fan and the lower lip of the air intake section in the longitudinal direction is smaller than the radius of the ducted fan;

[0030] A diffuser section is formed below the air intake section.

[0031] Furthermore, the ducted fan includes a rotor, a stator, a fan casing and a motor, wherein the rotor is connected to the shaft of the motor; one end of the stator is connected to the fan casing, and the other end is connected to the housing of the motor.

[0032] Furthermore, it also includes a tail cone connected to the motor, which forms a jet surface together with the exhaust section to generate maximum thrust.

[0033] As an embodiment disclosed in the present invention, the present invention also provides a distributed propulsion nacelle, wherein the distributed propulsion nacelle includes a plurality of detachable nacelle units arranged in parallel.

[0034] Furthermore, each distributed propulsion nacelle includes 2 to 8 nacelle units.

[0035] Furthermore, each of the distributed propulsion nacelles also includes an exhaust after-straightening portion, and each of the nacelle units includes a circular cross-section formed by an exhaust section, and the exhaust after-straightening portion is arranged in a triangular area between each circular cross-section.

[0036] As an embodiment disclosed in the present invention, the present invention also provides a new energy aircraft, which includes a fuselage, wings and the distributed propulsion nacelles, the wings are arranged on the left and right sides of the fuselage, and the distributed propulsion nacelles are arranged on the wings.

[0037] Furthermore, there are two sets of distributed propulsion nacelles, each set is arranged on the wing close to the fuselage.

[0038] Furthermore, each set of the distributed propulsion nacelles adopts a modular design, that is, it is composed of an innermost nacelle unit and an outermost nacelle unit arranged and combined along the wing span.

[0039] Furthermore, the innermost nacelle unit and the outermost nacelle unit have different outer shapes.

[0040] Specifically, if Figure 1As shown, the distributed nacelle 3 is divided into two sets, left and right, which are respectively installed on the inner side of the main wing (non-flap) of the left and right wings 2 near the fuselage 1. Each set of distributed nacelle 3 is composed of no less than two and no more than eight nacelle units 4, among which, except for the nacelle unit closest to the wing tip, the geometry of the remaining nacelle units is the same; in order to improve performance, the outermost nacelle unit is aerodynamically modified based on the inner nacelle shape, but the inner flow surface (including the nacelle air intake section 5, the ducted fan casing 6, and the nacelle exhaust section 7, see Figure 2 ) is consistent with the inner nacelle unit, thereby ensuring that its inlet and exhaust internal flow aerodynamic performance is consistent with the inner nacelle, which is conducive to simplifying the design of distributed power. Each set of distributed nacelle 3 adopts a modular design, that is, it is composed of the inner nacelle unit and the outermost nacelle arranged along the wing span. In order to facilitate ground maintenance and improve economic efficiency, each nacelle unit 4 of the distributed nacelle 3 can be disassembled and assembled independently. Figure 1 The left side shows the installed state of the distributed nacelles, and the right side shows the state where the middle nacelle unit 4 is independently removed.

[0041] Figure 2 Shown Figure 1 A cross-sectional view of the distributed nacelle in the installed state. For the nacelle unit, a ducted fan is installed inside, which includes a fan rotor 11, a stator 12, a fan case 6 and a motor 14, wherein the fan rotor 11 is connected to the shaft of the motor 14; one end of the stator 12 is connected to the fan case 6, and the other end is connected to the outer shell of the motor 14; the fan case 6 is connected to the wing structure through an appropriate mechanical connection (such as a mounting node, etc.). The function of the fan rotor 11 is to do work on the airflow to increase the total pressure of the airflow; the function of the stator 12 is to rectify the airflow after the rotor, converting the rotational airflow into an airflow along the axial direction of the motor to increase the thrust; the fan case 6 provides an inner flow surface, closes the inner flow channel, and the structure meets the requirements of rotor containment. The nacelle unit provides an intake section 5, an exhaust section 7 and a post-exhaust rectifying section 8 for the ducted fan. The air intake section 5 of the nacelle unit is a non-rotating body, which can realize the airflow transition from the non-circular air intake section of the distributed propulsion nacelle unit to the circular section of the duct fan, while the exhaust section 7 is a rotating body, which generates thrust with minimal loss, and the rotating shaft is the rotating shaft 13 of the fan. Figure 1 It can be seen that since each nacelle unit has at least one adjacent unit, there is a triangular area between the circular cross-sections of adjacent exhaust nozzles. The exhaust post-rectifier 8 is used to fill this area and eliminate the flow separation downstream of the nacelle exhaust to reduce the resistance. Figure 2 As shown, the tail cone 9 is also included, which forms a proper jet area with the exhaust section to generate maximum thrust. The tail cone 9 is directly connected to the motor 14.

[0042] Due to the different flight speeds and thrust requirements within the flight envelope of the aircraft, the ducted fan will have different intake flow requirements accordingly. The distributed nacelle needs to provide a stable, high-quality intake airflow for the ducted fan under typical working conditions, and its intake flow coefficient will vary between greater than 1 at low speed and less than 1 at high speed. In order to reduce the adverse effects of the intake flow coefficient less than 1 at high speed on the aerodynamic characteristics of the entire aircraft, the distributed nacelle adopts a sinking design, that is, the distance between the ducted fan shaft 13 and the lower intake lip 10 in the y direction (the x direction is the fan axis, and the y direction is the direction perpendicular to the x direction in the nacelle symmetry plane, and this direction is defined only for the convenience of description) is less than the radius of the ducted fan. For the intake airflow, the intake section 5 forms a diffuser section along the fan axis to decelerate and pressurize the airflow, providing the fan with appropriate incoming flow.

[0043] The design process of the independently detachable sunken distributed propulsion nacelle of the present invention is as follows:

[0044] 1) Determine the reasonable outer envelope of the distributed nacelle according to the selected geometric dimensions of the ducted fan, and decompose it into nacelle units with the same axial length, longitudinal height and span width for design, including the design of the air intake section, exhaust section, external flow surface and exhaust post-rectification design;

[0045] 2) By means of computational fluid dynamics, the overflow flow of the nacelle under the design conditions is analyzed, and based on this, the sinking amount of the distributed nacelle is adjusted so that the flow coefficient of the air intake is greater than 0.8 to reduce the overflow resistance and interference resistance, and a diffusion section is formed below the air intake section 5 in the xy plane. For aircraft with a flight speed greater than 0.25 Mach, the average expansion angle of the sunken nacelle air intake section is not less than 3° to ensure the drag reduction effect. The expansion angle is the angle between the front and rear end points of the lower contour line of the air intake section 5 and the x-axis, such as Figure 2 As shown in α; the inner manifold surface of the rotating exhaust section 7 of the nacelle unit is designed as required to ensure that the outlet cross-sectional area meets the design requirements and makes the cross-sectional area change evenly to reduce flow losses, and the exhaust post-rectifier 8 is used between the circular nozzles (exit cross section in the x direction) of the motor 14 to eliminate flow separation;

[0046] 3) To ensure that the distributed nacelle has good working conditions, the wing 2 matched with it is designed with a curved surface fusion, ensuring that the curved surface at the lower lip 10 of the air inlet section 5 is tangent to the surface of the wing 2 at the same position in space, ensuring smooth airflow;

[0047] 4) Repeat steps 2), 3), and 4) until the ideal internal flow aerodynamic characteristics are obtained, including the inlet total pressure recovery coefficient, inlet distortion, exhaust total pressure recovery, exhaust thrust coefficient, exhaust flow coefficient, and external flow aerodynamic characteristics (whole aircraft drag coefficient), and finally achieve a nacelle aerodynamic design that meets the requirements.

[0048] In summary, in terms of configuration, the existing design uses distributed nacelles to make two sets of left and right nacelles, each of which is integrated, that is, each nacelle cannot be independently disassembled and assembled. Although this will not affect the aerodynamic performance, it will make the design difficult to maintain during use. The present invention adopts a modular design for each distributed nacelle, that is, the inner nacelle unit and the outermost nacelle are arranged and combined along the wing span, and each nacelle unit of the distributed nacelle is set to be independently disassembled and assembled.

[0049] In terms of aerodynamics, the prior art adopts a non-sinking nacelle design. The non-sinking in the prior art refers to the height in the y direction from the lower lip 10 to the ducted fan shaft (see Figure 2 ) is the same as the fan radius. Such a design will result in a large frontal area of ​​the distributed nacelle designed for high-speed conditions, which will significantly affect the wing flow field and reduce the aerodynamic performance of the entire aircraft. The present invention adopts a sinking design for the distributed nacelle, that is, the distance between the ducted fan shaft and the lower air intake lip in the y direction is less than the ducted fan radius.

[0050] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0051] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not depart from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A nacelle unit for a new energy aircraft, characterized in that: The nacelle unit comprises: an air intake section, an exhaust section and a ducted fan; The ducted fan is arranged between the air intake section and the exhaust section; The air intake section is a non-rotating body, and the exhaust section is a rotating body; The nacelle adopts a sinking type, and the sinking type is achieved by a method in which the distance between the rotating shaft of the ducted fan and the lower lip of the air intake section in the longitudinal direction is smaller than the radius of the ducted fan; A diffuser section is formed below the air intake section.

2. The nacelle unit according to claim 1, characterized in that: The ducted fan comprises a rotor, a stator, a fan casing and a motor, wherein the rotor is connected to the shaft of the motor; one end of the stator is connected to the fan casing, and the other end is connected to the outer casing of the motor.

3. The nacelle unit according to claim 1, characterized in that: It also includes a tail cone connected to a motor, which together with the exhaust section forms a jet surface to generate maximum thrust.

4. A distributed propulsion nacelle, characterized in that: The distributed propulsion nacelle comprises a plurality of detachable nacelle units as described in any one of claims 1 to 3 which are arranged in parallel.

5. The distributed propulsion nacelle according to claim 4, characterized in that: Each distributed propulsion nacelle consists of 2 to 8 nacelle units.

6. The distributed propulsion nacelle according to claim 4, characterized in that: Each of the distributed propulsion nacelles also includes an exhaust after-flow fairing portion, and each of the nacelle units includes a circular cross-section formed by an exhaust section, and the exhaust after-flow fairing portion is arranged in a triangular area between each circular cross-section.

7. A new energy aircraft, characterized in that: The aircraft comprises a fuselage, wings and the distributed propulsion nacelle according to any one of claims 4 to 6, wherein the wings are arranged on the left and right sides of the fuselage, and the distributed propulsion nacelle is arranged on the wings.

8. The new energy aircraft according to claim 7, characterized in that: There are two sets of distributed propulsion nacelles, each of which is arranged on the wing close to the fuselage.

9. The new energy aircraft according to claim 7, characterized in that: Each set of the distributed propulsion nacelles adopts a modular design, that is, it is composed of an innermost nacelle unit and an outermost nacelle unit arranged and combined along the wing span.

10. The new energy aircraft according to claim 9, characterized in that: The innermost nacelle unit and the outermost nacelle unit have different outer shapes.

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