A rotor blade aerodynamic load simulation device and method

Abstract

The present disclosure discloses a rotor blade aerodynamic load simulation device, comprising a base, an aerodynamic load module and a clamping module are arranged on the base, wherein the clamping module is used for clamping a rotor blade; the aerodynamic load module is used for aerodynamic load simulation experiment on the rotor blade clamped by the clamping module. The device has simple structure, low cost, adjustable multi-directional angle of simulated blade excitation, wide coverage of excitation frequency, and excitation form closer to actual rotation.

Description

Technical Field

[0001] This disclosure pertains to the field of rotor blade modal testing, specifically relating to a rotor blade aerodynamic excitation simulation device and method. Background Technology

[0002] Turbines are crucial components widely used in systems such as aviation, shipbuilding, and energy industries. Rotor blades are one of the key components of turbines, typically operating under harsh conditions of high temperature, high pressure, and high speed. Blades are often subjected to complex forces such as aerodynamic loads, misalignment, and rotor imbalance, leading to abnormal vibrations and affecting their normal operation. Among these, aerodynamic loads are a significant factor influencing blade vibration. Understanding the impact of aerodynamic loads on blade vibration is beneficial for improving blade structural design and also provides guidance for rotor blade health monitoring.

[0003] Rotor blade vibration can be classified into synchronous vibration and asynchronous vibration based on whether the vibration frequency is an integer multiple of the rotational speed. Extensive experiments have shown that the excitation frequency of the airflow during blade rotation is often an integer multiple of the rotational speed. However, measuring the resonant frequency generated by airflow excitation during blade rotation using strain gauges is quite difficult, as blade rotation requires a complex electric slip ring system and telemetry system, significantly increasing costs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this disclosure is to provide a rotor blade aerodynamic excitation simulation device. The device has a simple structure and uses an air compressor to provide aerodynamic load for the rotor blade, which is closer to the actual working conditions.

[0005] To achieve the above objectives, this disclosure provides the following technical solutions:

[0006] A rotor blade aerodynamic load simulation device, comprising:

[0007] Base;

[0008] The base is equipped with a pneumatic load module and a clamping module, wherein,

[0009] The clamping module is used to clamp the rotor blades;

[0010] The aerodynamic load module is used to simulate the aerodynamic load on the rotor blades.

[0011] Preferably, the pneumatic load module includes:

[0012] The drive component is used to drive the aerodynamic load module to simulate the aerodynamic load on the rotor blades.

[0013] Preferably, the drive component includes a servo motor connected to a reducer.

[0014] Preferably, the aerodynamic load module further includes: an aerodynamic load assembly for simulating aerodynamic loads on the rotor blades under the drive of the drive assembly.

[0015] Preferably, the pneumatic load assembly includes a pneumatic slip ring, one side of which is connected to a drive assembly and the other side is connected to a nozzle rotary table.

[0016] Preferably, the clamping module includes: a four-axis micro-motion platform, on which a blade fixture is provided, and the blade fixture clamps and holds the blade.

[0017] Preferably, a strain gauge is attached to the root of the blade.

[0018] This disclosure also provides a method for simulating aerodynamic loads on rotor blades, including the following steps:

[0019] S100: The first-order modal frequency f of the blade is obtained through finite element simulation calculation. n ;

[0020] S200: Select the appropriate number of nozzles N and the motor frequency range [f] r1 f r2 ];

[0021] S300: Install the blade onto the blade fixture, and then install the blade fixture onto the four-axis micro-motion platform using two bolts;

[0022] S400: Adjust the four axes of the four-axis micro-motion platform to adjust the blades to the appropriate position and angle;

[0023] S500: Attach the strain gauge to the root of the blade and connect the strain gauge to the data acquisition system;

[0024] S600: Start the servo motor to control the nozzle rotary table speed to maintain at 60*f r1 During the rotation of the nozzle disc, the jetting airflow applies gas excitation to the blades.

[0025] Preferably, the method further includes the following steps:

[0026] S700: Start the data acquisition system to record the strain data of the blade during the excitation process, analyze the strain data to obtain the modal frequency of the blade.

[0027] Compared with the prior art, the beneficial effects of this disclosure are as follows: The device described in this disclosure has a simple structure, low cost, and the excitation of the simulated blade is adjustable in multiple directions and angles, with a wide coverage of excitation frequency, and the excitation form is closer to the actual rotation. Attached Figure Description

[0028] Figure 1This is a schematic diagram of the rotor blade aerodynamic load simulation device;

[0029] Figure 2 yes Figure 1 A schematic diagram of the gas load module in the device shown;

[0030] Figure 3 yes Figure 1 A front view of the clamping module in the device shown;

[0031] Figure 4 yes Figure 1 Side view of the clamping module in the device shown;

[0032] Figure 5 This is a schematic diagram of the recorded blade strain data;

[0033] Figure 6 This is a schematic diagram of the STFT time-frequency analysis results;

[0034] The markings in the attached diagram are explained as follows:

[0035] 1. Base; 2. Servo motor; 3. Reducer; 4. Coupling; 5. Slip ring support; 6. Pneumatic slip ring; 7. Rotor connecting shaft; 8. Y-type tee connector; 9. Nozzle; 10. Nozzle turntable; 11. Nozzle; 12. Four-axis micro-motion platform; 13. Motion platform base; 14. Blade tooling; 15. Blade; 16. Strain gauge. Detailed Implementation

[0036] The following will refer to the appendix. Figures 1 to 6 Specific embodiments of this disclosure are described in detail. While specific embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0037] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.

[0038] To facilitate understanding of the embodiments of this disclosure, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this disclosure.

[0039] In one embodiment, such as Figure 1 As shown, this disclosure provides a rotor blade aerodynamic load simulation device, comprising:

[0040] Base 1;

[0041] The base 1 is equipped with a pneumatic load module and a clamping module, wherein,

[0042] The clamping module is used to clamp the rotor blades;

[0043] The aerodynamic load module is used to simulate the aerodynamic load on the rotor blades.

[0044] The above embodiments constitute the complete technical solution of this disclosure. Compared with the prior art method of applying excitation to the blades through a vibrator for modal testing, this embodiment provides aerodynamic loads to the blades through compressed air, which is closer to the actual working conditions.

[0045] In another embodiment, the aerodynamic load module includes a drive component for driving the aerodynamic load module to simulate the aerodynamic load on the rotor blades, wherein the drive component specifically includes a servo motor 2, and the servo motor 2 is connected to a reducer 3.

[0046] In another embodiment, the aerodynamic load module further includes an aerodynamic load assembly for simulating aerodynamic loads on the rotor blades under the drive of the drive assembly.

[0047] In this embodiment, the pneumatic load assembly includes a pneumatic slip ring 6. By setting the pneumatic slip ring 6, the entanglement of the pneumatic pipeline during blade aerodynamic excitation can be prevented. The pneumatic slip ring 6 is fixed to the slip ring support 5 by bolts. One end of the pneumatic slip ring 6 is connected to the reducer 3 through the rotor connecting shaft 7 and the coupling 4, and the other end of the pneumatic slip ring 6 is fixedly connected to the nozzle turntable 10. Further, a plurality of evenly arranged Y-type tee connectors 8 are provided on the side of the nozzle turntable 10 near the pneumatic slip ring 6. Each Y-type tee connector 8 is led out from the pneumatic slip ring 6. A plurality of nozzles 11 are provided on the side of the nozzle turntable 10 away from the pneumatic slip ring. After the Y-type tee connectors split the flow, they are connected to the nozzles 11 through the nozzle pipes 9 (i.e., as shown in the image). Figure 2 As shown, each Y-type tee connector connects to two nozzles, and each nozzle connects to one spray nozzle.

[0048] In another embodiment, the clamping module includes:

[0049] The motion platform base 13 is equipped with a four-axis micro-motion platform 12, and a blade fixture 14 is installed on the four-axis micro-motion platform 12. The blade fixture 14 holds a blade 15, and a strain gauge 16 is attached to the root of the blade 15.

[0050] In this embodiment, as Figure 3 As shown, the four-axis micro-motion platform includes three translation axes (XYZ) and one rotation axis (RY). It should be noted that the height of the origin of the four-axis micro-motion platform (i.e., the midpoint of the blade fixture) is consistent with the height of the aerodynamic slip ring's axis; otherwise, the direction of the excitation force on the blade will shift, thus affecting the accuracy of subsequent blade modal frequency calculations.

[0051] In another embodiment, this disclosure also provides a method for simulating aerodynamic loads on rotor blades, comprising the following steps:

[0052] S100: The first-order modal frequency f of the blade is obtained through finite element simulation calculation. n ;

[0053] In this step, the first-order modal frequency of the blade is calculated using the following formula:

[0054]

[0055] Where m, c, and k represent the mass, damping, and stiffness of the blade, respectively.

[0056] S200: Select the appropriate number of nozzles N and the motor frequency range [f] r1 f r2 ], f r1 and f r2 Determined by the following formula:

[0057]

[0058] Where 'a' represents the gearbox reduction ratio and 'N' represents the number of nozzles.

[0059] S300: Install the blade onto the blade fixture, and then install the blade fixture onto the four-axis micro-motion platform using two bolts;

[0060] S400: Adjust the four axes of the micro-motion platform to adjust the blades to the appropriate position and angle;

[0061] S500: Attach the strain gauge to the root of the blade and connect the strain gauge to the data acquisition system;

[0062] S600: Start the servo motor to control the nozzle rotary table speed to maintain at 60*f r1 During the rotation of the nozzle disc, the jetting airflow applies gas excitation to the blades;

[0063] S700: Start the data acquisition system to record the strain data of the blades during the excitation process (e.g., ... Figure 5 As shown, the strain data is analyzed to obtain the modal frequencies of the blade.

[0064] In this step, after recording the strain data x(n) of the blade, it is also necessary to perform STFT time-frequency analysis on it, that is:

[0065] X(t, f) = ∑x(n)w(nt)e -j2πfn

[0066] Where x(n) represents the strain data of the blade, w(n) represents the window function, t represents the time point, f represents the frequency point, X(t, f) represents the time-frequency domain signal, π represents pi, and f n This represents the first-order modal frequency of the blade.

[0067] After the above time-frequency analysis, we can obtain the following: Figure 6 The modal frequencies of the blades shown are... Figure 6 In the figure, the horizontal axis (X-axis) represents time, the vertical axis (Y-axis) represents frequency, and the Z-axis represents the amplitude of the leaf resonance, expressed in chromatogram. The highlighted areas in the figure are the resonance peaks of the leaf, and the data X: 2.944, Y: 344, and Z: 46.47 represent the relevant parameters at the leaf resonance.

[0068] The above description, using specific embodiments, is merely for the purpose of aiding understanding and is not intended to limit the scope of this disclosure. Any modifications or substitutions made by those skilled in the art within the scope of the technology disclosed herein should be included within the scope of this disclosure.

Claims

1. A rotor blade aerodynamic load simulation device, comprising: Base; The base is equipped with a pneumatic load module and a clamping module, wherein, The clamping module is used to clamp the rotor blades; The aerodynamic load module is used to simulate the aerodynamic load on the rotor blades. The clamping module includes: a four-axis micro-motion platform, on which a blade fixture is provided, and the blade fixture clamps the blade; a strain gauge is attached to the root of the blade. The four-axis micro-motion platform includes three translation axes (XYZ) and one rotation axis (RY). The origin of the four-axis micro-motion platform is the midpoint of the blade fixture. The height of this origin is consistent with the axis height of the aerodynamic slip ring, so that the direction of the excitation force on the blade does not deviate, thereby avoiding affecting the accuracy of subsequent blade modal frequency calculations. The pneumatic load module includes: A drive component is used to drive the aerodynamic load module to simulate aerodynamic loads on the rotor blades; the drive component includes: a servo motor; A pneumatic load assembly is used to simulate aerodynamic loads on rotor blades under the drive of a drive assembly. A pneumatic slip ring, with a drive assembly connected to one side and a nozzle turntable connected to the other side.

2. The apparatus according to claim 1, wherein, The pneumatic load assembly also includes a slip ring support.

3. A method for simulating rotor blade aerodynamic loads based on any one of claims 1 to 2, comprising the following steps: S100: The first-order modal frequency of the blade was obtained through finite element simulation calculation. f n ; S200: Select appropriate nozzle quantity N and motor frequency range [ f r1 , f r2 ]; S300: Install the blade onto the blade fixture, and then install the blade fixture onto the four-axis micro-motion platform using two bolts; S400: Adjust the four axes of the four-axis micro-motion platform to adjust the blades to the appropriate position and angle; S500: Attach the strain gauge to the root of the blade and connect the strain gauge to the data acquisition system; S600: Start the servo motor to control the nozzle rotary table speed to maintain 60* f r1 During the rotation of the nozzle disc, the jetting airflow applies gas excitation to the blades.

4. The method according to claim 3, wherein, The method further includes the following steps: S700: Start the data acquisition system to record the strain data of the blade during the excitation process, analyze the strain data to obtain the modal frequency of the blade.

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