241 results about "Propulsive efficiency" patented technology

The invention relates to the technical field of ship propulsion, and discloses an energy-saving control method for a pre-rotating guide wheel of a ship propulsion system and a fluid optimization system. According to the invention, through a multi-dimensional cooperative control strategy and fluid structure optimization, an integrated system with dynamic prerotation compensation, self-adaptive flow regulation and vortex suppression functions is constructed. The control method comprises a multi-physical field sensor array, a guide wheel angle dynamic compensation algorithm and an energy efficiency optimization decision model, a deep learning algorithm is adopted to establish a mapping relation between a propeller wake flow field and guide wheel parameters, and 0.1-second-level dynamic response is achieved. According to the fluid optimization system, an asymmetric variable-curvature guide vane structure is innovatively designed, the optimal space distribution of guide vanes is determined through three-dimensional flow field simulation, and a flow guide channel with the pressure gradient self-adaptive characteristic is formed. A real ship verifies that the propulsive energy consumption can be reduced by 10%-25%, the propulsive efficiency can be improved by 15%-30%, the cavitation effect is effectively restrained, vibration noise is reduced, and remarkable economic benefits and environmental protection values are achieved.

The invention provides a ship main engine power real-time optimization method based on a hybrid network model, and belongs to the technical field of ship energy saving.A hybrid neural network model is constructed, the hybrid neural network model is based on a physical information neural network, a KAN network is introduced to serve as a front-end network structure, and the power of a ship main engine is optimized in real time; the high-dimensional nonlinear mapping module is used for establishing high-dimensional nonlinear mapping from navigational speed, a ship type parameter matrix, propulsive efficiency, fuel conversion efficiency and environmental factors to the minimum power of a main engine; a composite loss function is adopted to train the hybrid neural network model, wherein the composite loss function is formed by weighted summation of mean square error loss, dynamics constraint loss, propulsive efficiency constraint loss and fuel consumption constraint loss; using the trained hybrid neural network model to receive ship operation parameters and environment parameters collected in real time, and outputting a minimum power prediction value of the ship main engine through one-time forward propagation calculation to realize real-time optimization of the main engine power.

The invention provides an underwater propeller control method and system based on tensor recognition and fuzzy control. The underwater propeller control method and system are suitable for improving the propelling efficiency and adjustment intelligence in a complex flow field. According to the method, a wake flow simulation model is constructed based on geometric parameters and boundary conditions of a propeller, a rotation tensor and a strain tensor are derived after flow field data are obtained, and a tensor field index is extracted through function space mapping so as to determine a target grid region. A high-rotation candidate area is screened through a spectral clustering algorithm, a vortex structure is identified, and multi-dimensional features such as the scale, the strength, the axial direction and the vortex core position of the vortex structure are extracted. And constructing a state vector by combining the current propulsive efficiency and flow field disturbance parameters, inputting an adaptive fuzzy neural network model, reasoning a relationship between a vortex and an operation state, outputting a propeller rotating speed and an attack angle adjusting quantity, and realizing intelligent response and energy efficiency optimization of wake flow disturbance.

The invention discloses a three-degree-of-freedom pectoral fin cooperative motion control and gait optimization method, which comprises the following steps of: firstly, establishing a motion gait model of a three-degree-of-freedom rigid pectoral fin, and acquiring hydrodynamic feedback and attitude information of the pectoral fin under different input parameter combinations in real time by utilizing a multi-mode sensing system so as to construct a pectoral fin-environment interaction model; secondly, training a high-level strategy network by adopting a deep reinforcement learning algorithm, and optimizing a control signal cbase (t) by taking propulsive efficiency and attitude stability as reward functions; then, constructing a multi-layer hierarchical neural control network to decode cbase (t), outputting an incremental control signal delta c (t), and introducing a central mode generator network to generate a reference trajectory # imgabs0 # of each degree of freedom; finally, dynamic compensation of external disturbance and modeling errors is achieved based on a sliding mode control method of an extended state observer, delta c (t) is adjusted online through a performance evaluation index function J (t) to correct control parameters, pectoral fin motion is kept in the optimal propulsion and stable state all the time, closed-loop optimization is achieved, and the propulsion efficiency and attitude control capacity of the robotic fish are improved.

The present disclosure relates to a structure of pool cleaning robot, including a body, at least one driving unit arranged at one end of the body, a propeller arranged at the output end of the driving unit, and anti-vortex fins arranged on the propeller. The present disclosure uses propeller propulsion, and anti-vortex fins are arranged at the rear end of the propeller, which can eliminate the hub vortex cavitation generated by the propeller to reduce the pressure at the rear of the propeller and further reduce the induced resistance caused by the hub vortex cavitation, thereby improving the propulsion efficiency of the propeller.

The invention discloses a muck treatment capacity monitoring method and a muck treatment capacity monitoring system, and relates to the technical field of shield construction and muck treatment capacity prediction treatment, and the method comprises the following steps: collecting operation parameters of a shield tunneling machine deslagging and conveying link, calculating a muck flow coupling index, evaluating a deslagging link coupling state, and carrying out optimization; the load coupling index of the shield tunneling machine is calculated, the energy distribution balance is judged, and dynamic adjustment is conducted according to the unbalance state; calculating the energy consumption deslagging propulsion efficiency, evaluating the matching degree, and optimizing the power and conveying parameters of each link; a CNN and LSTM combined multi-scale modeling method is adopted to predict the future muck handling capacity, and online correction is carried out through a sudden change adaptive network; and finally, fusing the standardized data set with the actual operation parameters to generate a unit time muck handling capacity sequence. By means of the method, the deslagging and propelling matching degree of the shield tunneling machine can be improved, the energy utilization efficiency is optimized, and high-precision prediction and real-time regulation and control of the muck handling capacity are achieved.

The invention discloses a ship main propulsion intelligent control system based on multi-source data fusion, and relates to the technical field of ship main propulsion intelligent control. The problems that in the prior art, dynamic optimization is insufficient, the data fusion capacity is weak, energy efficiency is low, a fault-tolerant mechanism is passive, a control strategy is rigid, fault recovery is slow, the intelligent level is low, and complex environment changes cannot be handled are solved. According to the invention, by introducing a multi-source data fusion intelligent control algorithm, power distribution and battery scheduling of the ship main propulsion system are dynamically optimized, deep fusion is carried out in combination with environment data and equipment data, and the propulsion efficiency and energy management are improved; through multi-dimensional data fusion, system adaptability and fault-tolerant capability are improved, real-time adjustment and intelligent prediction are realized, fuel consumption is reduced, battery aging is reduced, and navigation stability is improved. The system further has an intelligent fault detection and prediction mechanism, manual intervention is reduced, and the fault-tolerant capability and the intelligent level of the system are improved.

The utility model provides an aircraft, which relates to the technical field of aircrafts and comprises an aircraft body, an aircraft frame, a front propeller and a rear propeller, the rack is rotationally connected to the fuselage around a pitch axis; the front thruster and the rear thruster are arranged at intervals along the longitudinal axis, and at least one of the front thruster and the rear thruster tilts relative to the fuselage around the axis parallel to the pitch axis. The rack can tilt around the pitch axis relative to the fuselage, so that the fuselage cannot tilt, and the stability of the aircraft is improved. In addition, the tilting rack can enable the front propeller and the rear propeller which tilt to the horizontal state to be staggered in the horizontal direction, so that pneumatic interference of the front propeller, the rear propeller and the aircraft body is reduced, and the propelling efficiency of the aircraft is guaranteed.

The invention provides a double-rotor direct-drive coaxial reverse-propeller electric ducted fan, which is characterized in that a single motor with an inner rotor and an outer rotor directly drives two pairs of blades, an intermediate transmission device and an inner rotor excitation group to generate a rotating magnetic field, and a first-stage propulsion component and a second-stage propulsion component with the same rotational inertia are driven under the action of electromagnetic torque with the same acting force and counter-acting force; one-way rotation deflection torque is balanced, and coaxial reverse propeller movement is achieved; the rectification duct reduces the induced resistance of the blades and improves the propulsive efficiency, the convergence and expansion guide sleeve and the motor frame body dissipate heat to form circulating heat dissipation of the Brayton heat engine, meanwhile, air is heated, expanded and ejected out to generate thrust, the efficiency is high, and the thrust is large. The dual-rotor motor direct-driven coaxial reverse propeller ducted fan propulsion unit is simple in mechanism, light in structure, large in power-to-weight ratio, high in reliability, beneficial to use in a narrow space and vertical take-off and landing, especially suitable for an EVTOL (electric vertical take-off and landing aircraft), and capable of promoting popularization of small aircrafts and vertical take-off and landing urban transportation carriers.

The invention provides an underwater running double-stator beam flow rim propeller structure which comprises a guide pipe, the interior of one end of the guide pipe is connected with a front propeller hub, a front propeller hub cap is installed at one end of a propeller shaft, a front deflection stator, a rim transmission device and a rear deflection stator are sequentially installed on the propeller shaft, and the front deflection stator is connected with the front deflection stator. The other end of the conduit is connected with the tail beam tube; the wheel flange transmission device comprises a wheel flange transmission ring, the wheel flange transmission ring is connected with a paddle, and the paddle is installed on the rotor inner shaft. The guide pipe is used as a connecting carrier of the stator, the rim and the beam tube, and the rim transmission device is used as a power source device of the propeller. The front torsion stator plays a role in enabling inflow of the rotor to generate prerotation, the rear torsion stator plays a role in adjusting the torsion angle of the blades according to the fluid speed so as to better absorb wake flow energy, and the beam barrel is used for restraining the wake flow and concentrating pressure at the tail of the propeller on beams in the same direction, so that the effect of improving the propelling efficiency is achieved.

According to the light helium storage spray pipe with the integrated efficiency of efficiency increasing, pushing changing, phase change heat prevention and infrared stealth, by means of the high phase change latent heat characteristic of liquid helium, the liquid helium is directly injected into the spray pipe to be mixed with high-temperature fuel gas; the temperature of fuel gas and thermal stress borne by a spray pipe material are remarkably reduced through phase change heat absorption, heat convection and gas film cooling, efficient thermal protection is achieved, the infrared radiation intensity of exhaust plume is effectively restrained, and the infrared stealth effect is achieved; the characteristic that helium is small in molecular weight is utilized, the expansion power capability of mixed gas and the propulsive efficiency and specific impulse of the engine are improved, meanwhile, through real-time regulation and control of helium injection flow, thrust adjustment to a certain degree can be achieved, and the maneuverability of the engine is enhanced. According to the designed composite interlayer structure, the thickness of the wall face of the spray pipe can be greatly reduced, the structural strength of the spray pipe is improved, and then the overall mass of an engine is reduced.

The invention discloses a clover-shaped superconducting magnetofluid thruster and a thrusting system.The thruster comprises a thrust generating module, a flow guiding module and a reversing transmission module, the thrust generating module comprises at least two superconducting coil assemblies and a protection shell, and the superconducting coil assemblies are rotationally connected into the protection shell; a seawater channel is formed in each superconducting coil assembly, the area of the cross section of each seawater channel is gradually reduced from the inlet end to the outlet end of the seawater channel, the flow guide module wraps the protective shell and is in a streamline shape from the inlet end of the seawater channel to the outlet end of the seawater channel, and the reversing transmission module is fixedly connected with the flow guide module. On the premise that the quiet performance is guaranteed, the propelling efficiency of the superconducting magnetofluid propeller is improved, and the navigation efficiency and navigation safety are guaranteed through cooperation of a series of intelligent devices.

The invention discloses a shaftless rim propeller with bearing and motor integrated driving steering. The shaftless rim propeller comprises a full-rotation device and a shaftless rim propelling unit. The full-rotation device comprises a main shell assembly and a full-rotation motor, the full-rotation motor is sleeved with the main shell assembly, the full-rotation motor comprises a water-lubricated bearing rotor and a first permanent magnet, and the first permanent magnet is embedded into the water-lubricated bearing rotor; the shaftless rim propelling unit comprises a propeller shell assembly, a spherical driving motor and blades, the propeller shell assembly is arranged on the outer side of the spherical driving motor in a sleeving mode and connected with the main shell assembly, and the spherical driving motor is in transmission connection with the blades. The structure of the full-rotation device is simplified, the structure is compact, a transmission mechanism is omitted, the full-rotation device is driven by the motor, and the full-rotation efficiency of the full-rotation device is improved. The three-degree-of-freedom rotation characteristic of the spherical motor is utilized, the propelling direction of propagation is adjusted in any direction, the propelling efficiency is improved, and the maneuverability of the ship under the non-design working condition is improved.

The invention discloses a ship propeller energy-saving rectifying device with diversion wings, and particularly relates to the technical field of ships, the ship propeller energy-saving rectifying device comprises a ship body, a driving rod is arranged at the rear end of the ship body, a propeller is arranged at the rear end of the driving rod, and a plurality of diversion wings are fixedly installed on the outer wall of the driving rod in an annular array mode. An L-shaped fixing support is arranged above the driving rod, the L-shaped fixing support is installed on the rear side of the ship body, a rectifying mechanism is installed at the bottom end of the vertical position of the L-shaped fixing support, the rectifying mechanism comprises an annular flow guide cover, and the propeller is located on the inner side of the annular flow guide cover. According to the ship propeller energy-saving rectifying device with the flow guide wings, through the synergistic effect of the flow guide wings and the rectifying mechanism capable of being dynamically adjusted, the inflow condition of the disc face of the propeller is improved, pre-rotation and non-uniformity of water flow are effectively weakened, and therefore the propelling efficiency of the propeller is improved, and fuel consumption and operation cost are reduced.

The invention discloses a composite propeller design method based on a regression neural network and a genetic algorithm, and belongs to the field of composite propellers. According to the method, the minimization of the distance from the pitch angle of the blade tip of the composite propeller to the optimal pitch angle of the propeller type under each working condition is taken as the optimization target of the propulsive efficiency, and the minimization of the absolute value of the difference value of the thrust coefficient KTA under the working condition of the low advance speed coefficient and the thrust coefficient KTB under the working condition of the high advance speed coefficient is taken as the optimization target of vibration and noise reduction; the constraint is that the strength of the structural performance of the composite material needs to meet a Tsai-Wu strength criterion, and constructing a ply pre-deformation optimization model; through combination of a regression neural network and a genetic algorithm, a layering angle sequence and pre-deformation geometric parameters of the composite material propeller are optimized, performance optimization of the composite material propeller in a full working condition range is realized under steady-state and non-steady-state working conditions, the balance between the minimum propulsion efficiency and vibration and noise reduction is realized, and the comprehensive performance of the composite material propeller is improved. Therefore, the working performance of the composite propeller is improved.

The invention discloses a water jet propulsion boat low-speed working condition energy-saving device based on the coanda effect. The water jet propulsion boat low-speed working condition energy-saving device comprises a flow guide plate, a fixed connecting piece and an angle adjusting device. The guide plate is arranged behind a nozzle of the water-jet propeller and is an S-shaped curved surface, the front end is hinged with the fixed connecting piece, and the rear end is hinged with the angle adjusting device; under a low-speed working condition, the guide plate rotates to a folded state, the upper wall surface covers a nozzle of the water-jet propeller and can guide jet flow to flow in a manner of being attached to the guide plate by means of the coanda effect, and the lower wall surface guides circulating vortex in a boat rear wake flow field; under the medium-high speed working condition, the guide plate rotates to a put-down state, the upper wall face is far away from jet flow of the water-jet propeller, and the lower wall face does not generate additional flow field disturbance in the boat body wake flow field. The jet flow of the water-jet propeller and the circulating vortex of the wake flow field of the boat body are guided based on the coanda effect, adverse flow coupling between the jet flow of the water-jet propeller and the circulating vortex is restrained, recycling of effective momentum in the corresponding wake flow field vortex is synchronously improved, and therefore the propelling efficiency of the water-jet propelling boat under the low-speed working condition is improved.

The application provides a variable impulse method for manta ray-like vehicle attitude control through bypass internal flow distribution, a propeller serving as a propelling system and a flow distributor with adjustable position arranged at an outlet end of a power duct module are fused and designed, axial water flow generated by the single propeller is directly used as propelling power and attitude control direct power, the flow of each jetting outlet can be adjusted without changing the propeller rotating speed through position adjustment of the flow distributor arranged at the outlet end of the power duct module, the impulse of water flow of upper and lower jetting outlets is quickly changed, upper and lower thrust difference is formed on the bionic body, the pitching moment is changed without changing the propelling process, the attitude adjustment of the bionic vehicle is accurately realized, and the system efficiency, dynamic response and task adaptability are coordinately improved on the basis of keeping the original propelling efficiency advantage.

The purpose of the present invention is to provide a hull-direct-connection-type propulsion device of a contra-rotating propeller and a method for manufacturing the same, the propulsion efficiency of an electrically propelled ship being greatly improved by disposing the contra-rotating propeller attached to the electrically propelled ship so as to be directly connected to the hull. In order to achieve the purpose, the hull-direct-connection-type propulsion device of the contra-rotating thruster according to the present invention comprises: a contra-rotating thruster comprising a front propeller and a rear propeller; a dual-rotor motor for generating respective rotation directions of the front propeller and the rear propeller; and the double shafts are used for connecting the contra-rotating thruster and the double-rotor motor.

The invention relates to a turbofan engine based on a multi-stage fan, which belongs to the technical field of aviation turbofan engines and comprises an inner duct, an outer duct, a high-pressure compressor system, a low-pressure compressor system, a high-pressure turbine, a low-pressure turbine and a multi-stage fan module. The high-pressure turbine drives the high-pressure compressor through the first transmission shaft, and the low-pressure turbine drives the low-pressure compressor and the multi-stage fan module through the second transmission shaft. And the multi-stage fan module comprises at least three stages of fans, transmits power and performs speed regulation and direction conversion through a gear set arranged on a second transmission shaft, so that the rotation directions of the odd-stage fans and the even-stage fans are opposite, and the rotation speeds of the odd-stage fans and the even-stage fans meet a certain proportional relation. The thrust load of the fan is dispersed to multiple stages of fan blades, so that the load of the fan blades is effectively reduced, the total thrust and the propulsive efficiency of the engine are improved, and meanwhile, the noise is favorably reduced.

The invention belongs to the technical field of floating equipment, and particularly relates to a tethered airship with a propelling device and a conveying system for the tethered airship. A connecting part is arranged on the outer surface of a boat body, a propelling device comprises a horizontal propelling part and a vertical propelling part, the horizontal propelling part is arranged on the peripheral surface of the boat body and used for moving the boat body in the horizontal direction, and the vertical propelling part is arranged on the peripheral surface of the boat body and used for moving the boat body in the vertical direction. The horizontal direction is perpendicular to the vertical direction, and the mooring rope is detachably connected with the connecting part. According to the tethered airship with the propelling device in the technical scheme, the horizontal propelling part is used for providing propelling force in the horizontal direction to achieve the functions of headwind adjustment, yaw control and the like of the airship body, and the vertical propelling part is used for providing pulling force in the vertical direction to achieve height adjustment and pitching control of the airship body. The propulsion device improves the propulsion efficiency of the boat body, and further enhances the wind measurement resistance and attitude stability of the boat body.

The invention relates to the related technical field of propelling devices, in particular to a wide-speed-range propelling device which comprises a flow guide cover and a mandrel, and the flow guide cover is arranged around the mandrel to form a flow channel for medium conveying; the rotor assembly is arranged in the flow channel and is used for generating propelling power; the stator assembly is arranged in the flow channel and comprises adjustable blades and an adjusting mechanism used for adjusting working parameters of the blades, and the adjusting mechanism can independently or cooperatively adjust attack angle parameters of the blades and / or distance parameters between the blades and the rotor assembly; the driving device is used for providing power for the adjusting mechanism; the propelling efficiency of the propelling device under different navigational speed working conditions is improved by adjusting attack angle parameters and / or spacing parameters of the blades. The wide-speed-range propelling device can work with high propelling efficiency under different navigational speed working conditions, and meanwhile the cruising ability of an aircraft is improved.

The invention provides an underwater propulsion vehicle device with high steering efficiency and low noise, and belongs to the technical field of underwater vehicle propulsion. The invention aims to meet the requirement of changing various sailing postures of the aircraft and ensure high steering efficiency and low noise. The sealed cabin comprises a sealed cabin body, a signal assembly, a lifter assembly and a propeller assembly. The signal assembly and the lifter assembly are installed on the sealed cabin body, and the propeller assembly is installed at the tail of the sealed cabin body. The thruster assembly comprises a rim thruster, a propeller, a transmission shaft component and a rudder component; the transmission shaft component is installed at the tail end of the sealed cabin body, and the propeller is installed on the transmission shaft component. The four rim propellers are distributed in a cross shape, connected with the sealed cabin body through rudder components and installed at the tail contraction position of the sealed cabin body. The condition of unreasonable layout of the rudder and the propeller at the tail contraction section of the aircraft is effectively improved, the problems of flow field disturbance and mutual interference caused by too close distance between the rudder and the propeller are avoided, the propelling efficiency is improved, and the flow noise is reduced.

This invention discloses a high-efficiency, low-noise waterjet propulsion pump, belonging to the field of marine engineering technology. The propulsion pump includes a shroud, a nozzle, a drive shaft, a drive shaft casing, a hub, an impeller, and a guide vane. The shroud and nozzle are connected, and the drive shaft and hub are coaxially connected and supported by the drive shaft casing inside the shroud and nozzle. The impeller and guide vane are fixed to the hub. The inner surface of the constricted nozzle at the rear of the impeller and guide vane has recesses, which are evenly distributed on the inner surface. This invention can reduce the flow resistance of the waterjet propulsion pump and improve propulsion efficiency.

The application discloses a flow field stabilizing mechanism of a double-throat aerodynamic vector nozzle and a control method thereof, which comprises two groups of guide vane arrays arranged in the double-throat aerodynamic vector nozzle and a servo control mechanism located outside the double-throat aerodynamic vector nozzle. When the double-throat aerodynamic vector nozzle is in a working state, according to the profile and flow field structure of the flow channel in the nozzle, the opening angle of the guide vane is adjusted through the servo control mechanism, so that the main flow of the double-throat aerodynamic vector nozzle is stabilized, and the vector performance of the double-throat aerodynamic vector nozzle is ensured, and the propelling efficiency and stability of the double-throat aerodynamic vector nozzle are improved.

The invention discloses a casting method of a marine copper alloy vortex eliminating fin. The casting method sequentially comprises the steps of manufacturing a wood pattern frame core box, manufacturing a pressure surface sand block, manufacturing a suction surface sand block, manufacturing a middle mud core sodium silicate sand core and manufacturing a flange rib plate sodium silicate sand core, assembling the cores, assembling a box, baking and pouring. During casting, precision casting and sand mold casting are combined, and the sand mold is free of sand crossing through core assembly modeling, so that the dimensional precision is guaranteed, and the efficiency is improved; the cost is reduced, and the product quality is ensured; according to the vortex elimination fin manufactured through the method, bubbles at the tail of a propeller are reduced, the cavitation effect is reduced, the hydrodynamic performance is enhanced, and therefore the propelling efficiency is improved.

An aircraft and an aircraft control method. The aircraft comprises: a fuselage (100), a frame (200), front propellers (300) and rear propellers (400), wherein the frame (200) tilts relative to the fuselage (100) about a pitch axis (001), with a tilt angle being adjustable; and the front propellers (300) and the rear propellers (400) are spaced apart along a longitudinal axis (002), and at least one of the front propellers (300) and the rear propellers (400) tilts relative to the fuselage (100) about an axis parallel to the pitch axis (001), with a tilt angle being adjustable. The frame (200) can tilt relative to the fuselage (100) about the pitch axis (001), thereby preventing the fuselage (100) from tilting and improving the stability of the aircraft. In addition, the tilted frame (200) can enable the front propellers (300) and the rear propellers (400) that are tilted to a horizontal state to be offset in a horizontal direction, thereby reducing aerodynamic interference of the front propellers (300), the rear propellers (400) and the fuselage (100), and ensuring the propulsion efficiency of the aircraft.

To provide a hull direct connection type propulsion device for a reciprocal rotation propeller greatly improving propulsion efficiency of an electric propulsion vessel by being composed so that the reciprocal rotation propeller loaded on the electric propulsion vessel is directly coupled to a hull, and a manufacturing method of the same.SOLUTION: A hull direct coupling propulsion device includes: a relative rotation propeller composed of a front propeller and a rear propeller; a double rotor electric motor generating respective rotational directions in a front propeller and a rear propeller; and a double shaft coupling the relative rotation propeller and the double rotor electric motor.SELECTED DRAWING: Figure 1

The invention relates to the technical field of ducted fans, and provides a ducted fan and a ducted fan unmanned aerial vehicle for fire fighting. The ducted fan comprises a ducted body, a fan body and a fan body, the wheel hub, the stationary blade and the movable blade are arranged in the flow channel, the stationary blade is connected with the wheel hub and the duct body, and the movable blade is rotatably arranged on the wheel hub; wherein the duct body comprises a main body section and a lip section which are arranged in the axial direction and connected, an inlet of the duct body is formed in the end, away from the main body section, of the lip section in the axial direction, an outlet of the duct body is formed in the end, away from the lip section, of the main body section, the inner diameter of the lip section is gradually reduced in the direction from the inlet to the outlet, and the lip section is provided with a plurality of through holes; the multiple through holes are formed in the circumferential direction of the lip section at intervals. According to the technical scheme, the pressure difference between the windward side and the leeward side of the lip area of the duct body can be reduced, the lateral resistance borne by the ducted fan is reduced, and then the propelling efficiency of the ducted fan is improved.

A vortex inducer is applied to the pressure face of a propulsion rotor blade. The vortex inducer defines an aft face located forward of the trailing edge of the blade. In operation, the vortex inducer generates a primary vortex behind its apex, which induces a counterrotating secondary vortex through viscous coupling at the trailing edge. The secondary vortex accelerates and deflects the suction face wake, enhancing overall blade performance. The system is applicable to propellers, helicopter rotors, prop-rotors, fan blades, and marine propellers.

The present invention discloses a ship tugboat shaft system fairing, comprising a fairing outer fairing with a trapezoidal cross section; a middle sleeve is provided at the middle position of the fairing outer fairing, a plurality of fairing plates with uniform spacing and divergence are installed between the middle sleeve and the inner wall of the fairing outer fairing, the fairing plates divide the interior of the fairing outer fairing into a plurality of fairing spaces of the same size, a swinging diverter plate is also installed between two adjacent fairing plates in the same fairing space, and the two fairing plates are provided with fixed mounting seats at the front sides at corresponding positions. In the present invention, the front ends of the swinging diverter plates are correspondingly mounted through fixed mounting seats and plug rods, the front ends of the swinging diverter plates can rotate, and the rear sides of the swinging diverter plates can swing; after such arrangement, the present invention further divides the fairing space into two areas through the swinging diverter plates, and when water flows through the two areas, the rear ends of the swinging diverter plates will swing according to the pressure of the water flow, thereby further increasing the propulsion efficiency.