Aerodynamic and mass imbalance coupled propeller automatic balancing device and method

Abstract

The application discloses a kind of propeller automatic balancing device and method of pneumatic and mass imbalance coupling, two the bearing seat is installed on base by hexagon bolt;Motor support is installed on the side of base, and with the mounting hole on base is aligned, and motor support is fixed with hexagon bolt;Stepless speed regulation motor is installed on motor support, two vibration measuring shaft sleeve is connected to the two predetermined measuring point positions of rotating shaft by stainless steel expansion sleeve, bearing is installed on bearing seat, and rotating shaft is installed and fixed by bearing.The shaft end of stepless speed regulation motor is connected with one end of rotating shaft by high-precision plum blossom coupling, and the other end of rotating shaft is installed propeller.The application realizes stepless regulation to wind speed in 0-7000rpm by speed regulating button, while ensuring the precision of blade angle adjustment.

Description

Technical Field

[0001] This invention provides an automatic balancing simulation test device and method for propellers for analyzing the law of aerodynamic and mass coupling vibration, specifically belonging to the research fields of automatic propeller balancing and analysis of the law of aerodynamic and mass coupling vibration. Background Technology

[0002] Propeller aircraft are aircraft that convert engine power into propulsion using a propeller. They offer advantages such as high thrust, high propulsion efficiency, and good economy during low-subsonic flight, making them promising for applications in military transport aircraft and regional airliners. Propeller engines are characterized by high safety, allowing for takeoff and landing in complex terrains, including grasslands and fields. The Tu-95 bomber and C-130 tactical transport aircraft possess advantages that jet aircraft cannot match. Taking the Russian Tu-95 bomber as an example, although it appears to use propeller engine technology, it incorporates some jet propulsion. This not only combines the high takeoff power of propeller engines but also lays the foundation for extended range. This allows the Tu-95 to achieve a maximum takeoff weight of 185 tons and a combat range of 14,000 kilometers. Using propeller engines not only saves on costs but also allows for increased payload. The propeller increases air intake, better driving the engine. Compared to jet engines, propeller engines not only have lower maintenance costs but also encounter less airflow when exceeding supersonic speeds, making them superior in terms of drag. However, during typical operating conditions such as dives, pitches, or high angles of attack, propeller aircraft experience uneven stress on the propeller, leading to engine rotor vibration and noise. Aerodynamic loads and unbalanced mass coupled vibrations are significant contributing factors. Extensive research has been conducted both domestically and internationally on engine rotor vibrations caused by unbalanced mass, resulting in the development of dynamic and automatic balancing techniques. These techniques have been widely applied to aero-engines, machine tools, and gas turbines, achieving remarkable results. However, effective experimental research equipment is still lacking for engine rotor vibrations caused by aerodynamic loads under typical operating conditions such as pitches, dives, and high angles of attack, as well as for aerodynamic-mass coupled vibrations. In view of this, this patent designs a set of test devices to simulate the aerodynamic load and unbalanced mass coupled vibration of a propeller engine under typical flight conditions, and to explore and analyze the vibration law of the engine rotor caused by aerodynamic load and the coupled vibration law of aerodynamic and mass imbalance under typical flight conditions.

[0003] Patent CN216842036U, published in 2022, discloses a serrated trailing edge flap for wind turbine load reduction and noise reduction. Its features include: a wind turbine nacelle; wind turbine blades fixedly connected to one side end face of the nacelle; both the nacelle and the blades being hollow structures; a serrated trailing edge flap at the trailing edge of the blades; a controller within the nacelle; and a drive device within the blades; the controller is electrically connected to the drive device; the controller can control the drive device to change the swing amplitude and frequency of the serrated trailing edge flaps, thereby reducing the aerodynamic load on the blades and the pressure distribution at the trailing edge, achieving the purpose of load reduction and noise reduction.

[0004] Patent CN114563155A, published in 2022, discloses an open rotor aerodynamic performance evaluation test device. This device uses a high-power motor as power input, driving two rows of blades of the open rotor to rotate in opposite directions at high speed via a high-power transmission system, thereby achieving efficient work by the open rotor. The device consists of a gearbox, output shafts, a rotating shaft balance, and a signal transmission system. The gearbox primarily accelerates the input power system and enables high-speed coaxial counter-rotating output. The gearbox input is connected to a drive motor, and the output consists of two coaxial counter-rotating output shafts. A rotating shaft balance is installed at the end of each output shaft, and the two rows of blades of the open rotor are connected to the output shafts via the rotating shaft balance. The rotating shaft balance is a six-component balance used to measure the aerodynamic load during the high-speed rotation of the open rotor. The signal transmission system primarily transmits the signals from the rotating shaft balance to a data acquisition system.

[0005] Patent CN102168646A, dated 2011, discloses a method and apparatus for balancing a rotor, the rotor comprising at least two rotor blades and a rotor shaft. The method for balancing the rotor of rotating machinery includes: receiving measurements of at least one of a load, acceleration, and displacement associated with at least one unbalanced load acting on the rotor shaft; and determining an angular compensation angle value of at least one rotor blade that contributes to reducing the at least one unbalanced load acting on the rotor shaft, wherein the at least one load imbalance is caused by at least one of the following: mass imbalance in the at least two rotor blades, rotor geometry irregularity, aerodynamic geometry difference between the at least two rotor blades, and angular zero point difference between the at least two rotor blades.

[0006] Patent CN105021350A (2015) discloses a method for assessing the mass imbalance of a steam turbine generator rotor. This method utilizes the magnitude and direction of the centrifugal force generated by the rotor's mass imbalance to evaluate the imbalance. The method for determining the magnitude and direction of this centrifugal force involves establishing a functional expression for the unbalanced magnetic pull Fe, the dynamic eccentricity ε, and the rotor's fundamental frequency amplitude A under basic operating conditions. Six different operating conditions are randomly selected from the steam turbine generator, grouped into three pairs. Within each pair, equations are established using the ratio of the resultant forces acting on the rotor under those conditions, resulting in three sets of equations. Solving these three sets of equations, each containing three unknowns, yields the magnitude and direction of the centrifugal force generated by the rotor's mass imbalance. This invention can accurately assess the mass imbalance of the generator rotor, providing support for unit dynamic balancing, avoiding the economic costs and start-up / shutdown hazards associated with repeated counterweighting, and enabling the unit's vibration to quickly return to normal levels.

[0007] Patent CN216741838U (2022) discloses an experimental unit for simulating typical mechanical faults in the shaft system of a wind turbine generator. This experimental unit includes a bottom fixed plate, a DC drive motor, a simulated generator, and a coupling. The DC drive motor is fixed to the bottom fixed plate. The simulated generator includes a generator stator and a generator rotor. The generator stator is fixed to the bottom fixed plate, and the rotor shaft on the generator rotor extends beyond both ends of the generator stator, with bearings fixed on the rotor shaft. The bearings are supported by bearing seats, which are fixed to the bottom fixed plate. The output shaft of the DC drive motor is connected to one end of the rotor shaft via a coupling, and the other end of the rotor shaft is connected to a blade mass imbalance adjustment mechanism. This invention can intuitively and conveniently simulate different degrees of air gap dynamic eccentricity faults, blade mass imbalance faults, and bearing faults, and can also simulate mixed faults, thus providing a foundation for the analysis, research, and prevention of mechanical faults in the wind turbine generator drivetrain.

[0008] Patent CN106768642A (2017) discloses a mechanical device for achieving online automatic balancing of rotating machinery. This device has a split structure, comprising a split rotating ring and a split stationary ring. A split transition sleeve connects the rotating spindle to the rotating ring and also supports the rotating ring. The split components of the stationary ring are axially connected and fixed in series via stationary ring set bolts. The stationary ring, with its split structure, circumferentially wraps around the rotating ring. The split surfaces of the rotating ring's components are connected using bolts, plug-in joints, connecting plates, etc., and are axially fixed in series via the rotating ring set bolts. This split structure makes the automatic balancing device suitable not only for new product development but also for in-service rotating equipment. It greatly improves the ease and convenience of installation and disassembly of the automatic balancing head, allowing for assembly and disassembly of the automatic balancing device without disassembling the original device, thus facilitating the application and promotion of automatic balancing devices.

[0009] Patent CN114576310A (2022) discloses a large-diameter hydraulic automatic balancing actuator. An intermediate sleeve is interference-fitted onto the outer wall of a liquid storage pan. Four axially arranged gas flow grooves are provided on the outer wall of the intermediate sleeve. Four axially arranged gas injection channels of varying depths are provided at the bottom of the stator, corresponding one-to-one with the gas flow grooves. The liquid storage pan includes four circumferentially distributed liquid storage chambers. Gas injection pipes are installed within each liquid storage chamber and connected to the gas flow grooves. Connecting pipes connect the oppositely arranged liquid storage chambers. Gas enters the four liquid storage chambers through four solenoid valves, four gas channels corresponding to the four gas injection channels, and through the elongated holes at the bottom of the gas flow grooves and the gas injection pipes. During operation, there is no liquid injection or drainage process. The on / off time of the solenoid valves is controlled by a controller, injecting compressed gas to drive a quantitative balancing liquid to transfer between the opposite liquid storage chambers. Two pairs of liquid storage chambers are vector-synthesized to obtain a compensation vector equal in magnitude and opposite in direction to the imbalance, thus canceling the imbalance.

[0010] Other related patents include: Patent No. CN114323547A, a wind tunnel test aerodynamic load measurement device and method; Patent CN103207942A, a method for calculating the uneven force of the actuator disk load based on momentum-blade element theory; Patent CN103913272A, a quantitative diagnosis method for rotor mass imbalance fault of steam turbine generator set; Patent CN112417611A, an automatic balancing structure design method based on magnetic circuit optimization; and Patent CN113705033A, a lightweight design method for electromagnetic automatic balancing device. Analysis of publicly available patent technologies reveals that current automatic rotor balancing only considers rotor mass imbalance. It does not address the coupling vibration of aerodynamic loads and mass imbalance under typical operating conditions such as pitch, high angle of attack cruise, and dive in propeller aircraft. Propeller aircraft, due to their high thrust, high efficiency, good economy, and strong terrain adaptability, are widely used in the military fields of various countries and have broad prospects. However, there is a lack of targeted testing equipment. Most existing testing equipment focuses on rotor mass imbalance. Therefore, there is an urgent need for testing equipment to study aerodynamics and the coupling vibration law of aerodynamics and mass imbalance. Summary of the Invention

[0011] The purpose of this invention is to address the aerodynamic and mass imbalance coupled vibration problem of propeller engines under typical flight conditions. Under typical flight conditions, propeller engine imbalance vibration is primarily caused by aerodynamic and mass imbalances, with these two factors coupled. This invention focuses on the study of aerodynamic loads on rotor vibration and unbalanced mass-induced rotor vibration under typical flight conditions, particularly pitch, dive, and high angle-of-attack flight. It also addresses the complex signals exhibited under fundamental and blade frequency coupled vibrations, resulting in complex vibration characteristics, difficulties in fault diagnosis, and challenges in vibration suppression. Therefore, this invention designs an experimental device to simulate and test the vibration generated by aerodynamic loads on the rotor and the coupled vibration of aerodynamic and mass imbalance under typical flight conditions in propeller aircraft. Furthermore, it utilizes fluid-structure interaction (FSI) simulation methods to systematically simulate and test the vibration of aerodynamic loads on the rotor and the coupled vibration of aerodynamic and mass imbalance under typical flight conditions. Through analysis of the FSI simulation results and experimental data, the aerodynamic and mass imbalance coupled vibration characteristics of propeller engines under typical flight conditions are derived. This invention primarily focuses on the analysis and research of the influence of aerodynamic loads, unbalanced mass, and aerodynamic-mass coupling on propeller rotor vibration under typical flight conditions. This patent designs an automatic balancing test device and analysis method that can simulate typical flight conditions of propeller engines, such as pitch, dive, and high angle-of-attack flight, enabling online identification of aerodynamic-mass coupled vibrations and providing accurate control input for the propeller automatic balancing system.

[0012] A simulation test device for analyzing and studying the aerodynamic and mass coupling vibration law of a propeller engine includes a base, a bearing seat, a rotating shaft, a continuously variable speed motor, and a motor support.

[0013] Two bearing housings are mounted on the base using hexagonal bolts; a motor bracket is mounted on one side of the base, aligned with the mounting holes on the base, and secured with hexagonal bolts; a continuously variable motor is mounted on the motor bracket; two vibration measuring sleeves are connected to two predetermined measuring points on the rotating shaft via stainless steel expansion sleeves; bearings are installed on the bearing housings, and the rotating shaft is fixed in place by the bearings. The shaft end of the continuously variable motor is connected to one end of the rotating shaft via a high-precision perforated coupling, and a propeller is mounted on the other end of the rotating shaft.

[0014] In the propeller structure, the propeller blades 11 are mounted on one end of the blade adapter 10, and the other end of the blade adapter 10 is connected to the hub 12. The angle of the blades 11 is adjusted to form a complete propeller. The expansion sleeve 13 is inserted into the center hole of the hub 12 to combine with the hub 12. The interface of the blades 11 is aligned with the fixing hole of the blade adapter 10 and fixed with bolts. At the same time, set screws are installed in the set screw holes 20 on both sides of the fixing hole of the blade adapter 10 to fix the left and right sides of the blades, preventing the blades 10 from wobbling from side to side during propeller rotation, which would affect the accuracy of the test results. The assembly of blade 11 and blade adapter 10 is connected to the fine thread hole in the hub 12 through the fine thread 18 at the end of the blade adapter. At the semicircle of the blade adapter 10, the blade 11 can change its angle as the blade adapter 10 rotates. At the same time, this combination of blade 11, blade adapter 10 and hub 12 can freely combine the number of blades. This test device can realize relevant tests on propellers with different numbers of blades, such as 2 blades, 3 blades, 4 blades and 6 blades.

[0015] To ensure rotor rotation stability in this test setup, a single-bearing-base, double-bearing support structure is employed. One deep groove ball bearing 15 is pre-installed in the bearing housing 7, followed by the insertion of a bearing retainer ring 14. Then, another deep groove ball bearing 15 is pre-installed and secured by the bearing end cap 16 to prevent axial movement. The bearing retainer ring 14 ensures the alignment of the two bearings 15. This design not only strengthens the support but also guarantees the alignment between the two deep groove ball bearings, minimizing the impact of rotor misalignment on the accuracy of the test results due to the significant second harmonic distortion.

[0016] The power output design of the test device utilizes an external permanent magnet high-speed DC motor and a high-precision perforated coupling 5 to transmit power torque. The rotor's power transmission is achieved through the high-precision perforated coupling 5, which connects the output power end of the permanent magnet high-speed DC motor 3 to the rotor shaft end. The drive motor 3 is mounted on an L-shaped motor bracket 2 via positioning holes and hexagonal bolts, while the L-shaped motor bracket 2 is mounted on a base 1 via hexagonal bolts. A stepless speed regulation of 0-7000 rpm is achieved through a motor speed controller with a digital display, allowing for simulation testing of propeller aerodynamic loads at different speeds.

[0017] The structure for changing the incoming flow angle and velocity consists of a base plate 21, a semi-circular dial 22, an angle pointer 24, and an air source 23. First, the semi-circular dial 22 is fixed to the base plate 21 with screws. The pointer is installed at the center of the base plate 21, and the pointer 24 is connected to the air source 23. The rotation of the pointer 24 drives the rotation of the air source 23, thus changing the angle between the incoming flow and the propeller shaft. This simulates the vibration of the rotor caused by aerodynamic loads during different flight attitudes of a propeller aircraft, such as pitch, dive, cruise, and high angle of attack, as well as the aerodynamic and mass coupling vibration laws. The incoming flow velocity is provided by an axial flow fan. This axial flow fan can achieve stepless speed regulation of the incoming flow velocity, generating an axial wind speed within the range of 0-10 m / s. Combined with a wind speed sensor, precise control of the incoming flow velocity can be achieved, preventing wind speed loss due to fan distance from causing large errors in experimental results.

[0018] The method described above combines fluid-structure interaction (FSI) simulation. FSI is defined by a set of coupling equations that simultaneously involve the fluid domain and the solid domain (structure). Load transfer occurs between the two through the Fluid-Solid interface, effectively saving analysis time and cost. Furthermore, because the fluid structure is calculated simultaneously, the results more closely approximate the laws governing the physical phenomena themselves. FSI is an independent branch of mechanics arising from the intersection of fluid mechanics and solid mechanics. It studies the various behaviors of solids under fluid influence and the impact of solid deformation or motion on the flow field. Currently, FSI methods are widely used in mechanical, power, energy, aerospace, chemical, and nuclear industries. Particularly in the aerospace field, with the rapid development of the aerospace industry, aero-engines are evolving towards higher loads, higher efficiency, and higher reliability. High loads leading to high adverse pressure gradients easily cause flow separation. Simultaneously, with technological advancements, aero-engine design materials are becoming increasingly lighter and thinner, significantly increasing the impact of unstable internal flow on the blades, making it one of the key issues in engine aerodynamic structure design. However, considering only aerodynamics or structure is often insufficient for practical needs; it is essential to combine aerodynamics and structure, taking into account their interactions. Therefore, fluid-structure interaction (FSI) is widely used in the aerospace field. This experimental setup incorporates FSI simulation. First, high-fidelity modeling of each component of the setup is performed in 3D modeling software to ensure the geometry of the model is highly consistent with the experimental setup. Then, the high-fidelity model is imported into the ANSYS preprocessing module to match the materials of each component with those of the experimental setup. For FSI simulation, the external flow field also needs to be consistent with the experimental setup to prevent significant deviations between simulation and experimental results due to inconsistent flow field magnitudes, thus affecting the accuracy of the experimental results.

[0019] The implementation steps of the fluid-structure interaction method are as follows:

[0020] S1 uses SOLIDWORKS modeling and simulation software to create a three-dimensional model of the propeller test device based on the CAD two-dimensional drawings.

[0021] S2 simplifies the model appropriately based on theoretical calculations;

[0022] S3 imports the established propeller test device model into the ANSYS Fluent and ANSYS Transient modules, and connects the results of the two modules to the couplesystem module, so that the data of the two modules can be transferred to each other, forming a fluid-structure interaction.

[0023] S4 creates internal and external flow fields in the ANSYS Fluent module to simulate the external environment of a propeller engine during flight.

[0024] S5 performs mesh generation on the 3D model of the propeller test device of ANSYS Fluent and ANSYS Transient modules respectively, and performs mesh independence verification.

[0025] S6 sets the simulation conditions and a reasonable simulation time step, and begins the calculation;

[0026] After the S7 calculation is completed, the simulation calculation data is exported to MATLAB for data processing.

[0027] Compared with existing technologies, the automatic balancing test system and method of the present invention for studying the influence of aerodynamic loads on rotor vibration and the coupled vibration law of aerodynamic and mass imbalance has the following advantages:

[0028] 1. It has independently designed external test conditions for variable airflow size and direction. By using the angle relationship between the pointer on the semi-circular dial and the dial, the angle of the incoming flow can be precisely adjusted. The adjustment accuracy can reach 1 degree each time. At the same time, with the axial flow fan, it can stably output directional airflow. The wind speed can be steplessly adjusted from 0 to 7000 rpm through the speed adjustment button.

[0029] 2. In terms of the structure of the test device, an innovative design is adopted to adjust the blade angle and the number of blades. By adjusting the angle relationship between the scale line on the blade adapter and the scale mark on the blade hub, different blade angles can be accurately obtained with an accuracy of 2 degrees. At the same time, the flexible and detachable blades can be used to test propellers with different numbers of blades. The connection between the blade mounting joint and the blade hub adopts a 0.35mm fine thread connection, which ensures both safety and blade angle adjustment accuracy.

[0030] 3. This experimental setup can conduct tests under different coupled operating conditions. It can test aerodynamic load factors such as the angle and velocity of the incoming flow, blade angle, number of blades, and propeller rotation speed. Furthermore, it can simulate the coupled vibration of a propeller engine under simultaneous aerodynamic loads and unbalanced mass conditions during flight by adding an unbalanced mass to the rotor hub, and analyze the aerodynamic and mass-coupled vibration laws of the rotor, providing suggestions for the study of aerodynamic and mass-coupled vibration laws in aero-engines.

[0031] 4. This experimental setup can be combined with fluid-structure interaction (FSI) simulation methods. By establishing a high-fidelity simulation model of the experimental setup, experiments and simulations can be conducted simultaneously. FSI can fully reproduce experimental conditions and effectively save analysis time and costs. It fully considers the interaction between fluids and structures, ensuring the highest possible consistency of experimental results. Therefore, FSI has been widely used in the field of aerospace structural design. Attached Figure Description

[0032] Figure 1 3D design drawing of propeller test device.

[0033] Figure 2 3D model of propeller components.

[0034] Figure 3 3D structural design drawing of bearing housing.

[0035] Figure 4 3D structural design drawing of the propeller.

[0036] Figure 5 Three-view drawing of the propeller blade (including the rear view).

[0037] Figure 6 , 3D design drawing of rheometry angle device.

[0038] Figure number annotation:

[0039] Figure 2 In the middle, 1 base, 2 motor bracket, 3 motor, 4 motor shaft shoulder positioning, 5 coupling, 6 bearing end cover, 7 bearing seat, 8 shaft, 9 vibration measuring shaft sleeve, 10 propeller hub, 11 propeller blade, 12 propeller blade adapter, 13 shrink sleeve, 14 bearing retaining ring, 15 bearing.

[0040] Figure 3 In the middle, there is a bearing end cap for bearing 6, a retaining ring for bearing 14, and bearing 15.

[0041] Figure 4 In the middle, there are 16 blade end fixing holes, 17 fine thread, 18 blade positioning holes, and 19 set screw holes.

[0042] Figure 5In the middle, there are 10 propeller hubs, 11 propeller blades, 12 propeller blade adapters, 13 tensioning sleeves, and 20 counterweight holes.

[0043] Figure 6 In the center, 21 is the base plate, 22 is the semi-circular dial, 23 is the air source (axial flow fan), and 24 is the pointer. Detailed Implementation

[0044] To make the objectives and advantages of the present invention clearer, the present invention will be described in further detail below.

[0045] Example 1: Taking the vibration of the propeller shaft caused by aerodynamic loads under typical flight conditions such as pitch and dive of a simulated propeller engine, as well as the aerodynamic-mass coupled vibration, as an example, this example specifically illustrates the mechanical structure installation and fit relationship of the propeller test device, the control form and speed regulation method of the drive motor, and the test method of the test software. Figure 6 The various structural mechanical components of the experimental device are assembled into the main body of the propeller test device. Two bearings are installed in predetermined positions, and the propeller blades are installed on the blade adapter. Finally, the blades are connected to the hub via the fine-pitch thread of the blade adapter. The hub is fixed to the shaft end by a tensioning sleeve. The motor bracket is fixed to the base, and the motor is then bolted onto the motor bracket. A high-precision perforated coupling is used to connect the motor shaft end and the shaft. The vibration measuring sleeve is then installed to the designated measuring point via the tensioning sleeve. Next, the inflow angle converter is installed, placing the entire inflow angle converter in the pre-reserved position on the base (in front of the propeller). The inflow angle and wind speed are adjusted. Finally, the assembled test device is checked for looseness in the tensioning sleeve, coupling, and all bolt connections. Additionally, the power supply lines of the drive motor and the control lines of the speed control device must be checked for correct and secure connections. After verification, the eddy current sensor and accelerometer were placed at the designated measuring points. The signals measured by the sensors were input into the computer using the Longcheng International multi-channel equipment fault diagnosis system. The computer software interface displayed the time-domain and frequency-domain graphs of the vibration displacement in real time, and the test results were saved using the software's save function for subsequent analysis and research. Under the same conditions, an unbalanced mass was added to the counterweight hole of the propeller hub to simulate the typical working condition of aerodynamic and mass imbalance vibration. The above test operation was repeated, and the test results of aerodynamic and mass coupled vibration were recorded.

[0046] Example 2: Taking the vibration of the propeller shaft under the aerodynamic load of a typical propeller engine at a high angle of attack as an example, this example specifically illustrates the mechanical structure installation and fit relationship of the propeller test device, the control form and speed regulation method of the drive motor, and the testing method of the test software. The debugging and installation of the propeller test device are the same as in Example 1, so they will not be repeated. After determining the above test conditions, the incoming wind speed and incoming angle are fixed. The blade angle is adjusted by the precise fit between the fine thread on the blade adapter and the blade hub, and the adjustment accuracy can reach 2 degrees. The influence of the angle of attack change on the propeller shaft vibration can be analyzed. In addition, the coupled vibration law of aerodynamics and mass under the typical flight condition at a high angle of attack can also be simulated by adding an unbalanced mass to the counterweight hole of the blade hub.

Claims

1. An automatic propeller balancing device coupled with aerodynamic and mass imbalance, characterized in that, Includes base, bearing housing, rotating shaft, continuously variable speed motor, motor bracket, incoming flow angle and incoming flow velocity structure; The two bearing housings are mounted on the base with hexagonal bolts; the motor bracket is mounted on one side of the base and aligned with the mounting holes on the base, and is fixed with hexagonal bolts; the continuously variable motor is mounted on the motor bracket, and two vibration measuring sleeves are connected to two predetermined measuring points on the rotating shaft through stainless steel expansion sleeves. Bearings are installed on the bearing housings, and the rotating shaft is fixed by the bearings; the shaft end of the continuously variable motor is connected to one end of the rotating shaft through a high-precision plum blossom coupling, and a propeller is mounted on the other end of the rotating shaft. In the propeller structure, the propeller blades are mounted on one end of a blade adapter, and the other end of the blade adapter is connected to the hub. The blade angles are adjusted to form a complete propeller. An expansion sleeve is inserted into the center hole of the hub to combine with the hub. The blade interface is aligned with the fixing hole of the blade adapter and fixed with bolts. Set screws are installed in the set screw holes on both sides of the fixing hole of the blade adapter to fix the left and right sides of the blade. The combination of blade and blade adapter is connected to the fine thread hole in the hub through the fine thread at the end of the blade adapter. Different blade angles are obtained by adjusting the angle between the scale line on the blade adapter and the scale mark on the hub. The number of blades can be freely combined by the combination of blade, blade adapter and hub. The incoming flow angle and velocity structure consists of a base plate, a semi-circular dial, an angle pointer, and an air source. The semi-circular dial is fixed to the base plate with screws, and the pointer is installed at the center of the base plate. The pointer is connected to the air source, and the rotation of the pointer drives the rotation of the air source, thereby changing the angle between the incoming flow and the propeller shaft. This simulates the vibration of the rotor caused by aerodynamic loads and the aerodynamic and mass coupling vibration law of a propeller aircraft in different flight attitudes. The incoming flow velocity is provided by an axial flow fan, which achieves stepless speed regulation of the incoming flow velocity, generating an axial wind speed in the range of 0-10 m / s. Combined with a wind speed sensor, the incoming flow velocity is precisely controlled. An unbalanced mass is added to the counterweight hole of the propeller hub to simulate the typical working conditions of aerodynamic and mass imbalance vibration.

2. The automatic propeller balancing device coupled with aerodynamic and mass imbalance according to claim 1, characterized in that, The continuously variable speed motor is a permanent magnet high-speed DC motor. Power torque is transmitted through a high-precision perforated coupling. The power transmission of the rotor is achieved through the high-precision perforated coupling that connects the output power end of the permanent magnet high-speed DC motor to the rotor shaft end. The drive motor is mounted on the motor bracket through positioning holes and hexagonal bolts, and the motor bracket is mounted on the base through hexagonal bolts. Stepless speed regulation from 0 to 7000 rpm is achieved through a motor speed controller with digital display, and simulation tests are conducted on the propeller aerodynamic load at different speeds.

3. The automatic propeller balancing device coupled with aerodynamic and mass imbalance according to claim 1, characterized in that, The fluid-structure interaction method of this device is implemented in the following steps: S1 uses SOLIDWORKS modeling and simulation software to create a three-dimensional model of the propeller test device based on the CAD two-dimensional drawings. S2 simplifies the model based on theoretical calculations; S3 imports the established propeller test device model into the ANSYS Fluent and ANSYS Transient modules, and connects the results of the two modules to the couple system module, so that the data of the two modules can be transferred to each other, forming a fluid-structure interaction. S4 creates internal and external flow fields in the ANSYS Fluent module to simulate the external environment during propeller engine flight. S5 performs mesh generation on the 3D model of the propeller test device of ANSYS Fluent and ANSYS Transient modules respectively, and performs mesh independence verification. S6 sets the simulation conditions and a reasonable simulation time step, and begins the calculation; After the S7 calculation is completed, the simulation calculation data is exported to MATLAB for data processing.

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