Wind tunnel flutter test method of wind power blade elastic scaling model in rotating state

Abstract

The invention discloses a wind tunnel flutter test method for a wind power blade elastic scaling model in a rotating state, and belongs to the technical field of wind tunnel flutter tests. When a wind tunnel flutter test of an elastic similar scaling model of a large wind power blade is carried out, data such as blade displacement, acceleration and torque can be obtained by implementing the test through the scheme, and comparison with simulation analysis is facilitated. According to the invention, the problems of device arrangement and acquisition equipment arrangement of the flutter test platform of the rotating blade are solved, and the whole set of process is subjected to actual inspection and is simple to operate and reliable to run.

Description

Technical Field

[0001] The invention relates to a wind tunnel flutter test method for an elastic scaled-down model of a wind turbine blade in a rotating state, and belongs to the technical field of wind tunnel flutter tests. Background Art

[0002] Flutter research is an indispensable part of the design process of large wind turbine blades today, and wind tunnel flutter testing is an important part of flutter research. Since flutter has many forms, the mathematical and physical relationships that need to be considered when calculating the critical flutter speed are very complex. Therefore, in the design process of large wind turbine blades, the wind tunnel flutter test can be used to verify whether the wind turbine blades will flutter. According to the survey, no one in China has conducted wind tunnel flutter tests on rotating wind turbine blades, and the test technology is not mature enough. The existing wind tunnel flutter test scheme does not take into account the rotation of the blades. People are eager to find a simple, reliable and efficient design scheme for wind tunnel flutter tests on wind turbine blades. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a safe, reliable and simple test scheme to collect detailed and accurate experimental data in view of the shortcomings of the existing wind tunnel flutter test process method under the rotating state of wind turbine blades.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: a wind tunnel flutter test method of an elastic scaled model of a wind turbine blade in a rotating state comprises the following steps: S1. Use the reduction theory to design an elastic similarity model of a large flexible blade. An acceleration sensor is installed on the trailing edge of the blade tip of the model blade, and a strain gauge is installed on the blade web near the blade tip. S2. The motor, bearings and slip rings are arranged on the mounting platform, and a support frame is arranged at the bottom of the mounting platform; the motor drives the motor shaft, and the motor shaft is supported by the bearing; the blade root joint is cylindrical, which is convenient for adjusting the pitch angle, and the hub connects the blade and the motor shaft; S3. A dynamic measurement system is arranged at the wind tunnel outlet to measure the displacement response of the model operation; S4. The strain gauge on the blade collects the signal and transmits the signal using a wireless transmission device, which is installed on the hub; S5. A slip ring is installed between the wheel hub and the motor shaft to transmit the acceleration signal; the motor shaft passes through the slip ring, the slip ring stator is connected to the slip ring rotor, the slip ring stator is connected to the mounting platform by bolts, and the acceleration signal is transmitted by the slip ring; S6. The torque meter is installed on the motor shaft after the slip ring to measure the real-time torque of the wind turbine; S7. Install a motor behind the torque meter along the airflow direction to directly force the speed to be out of the critical speed when flutter occurs.

[0005] The beneficial effects of the present invention are: the scheme of the present invention is simple, reliable and efficient. When conducting a wind tunnel flutter test on an elastic similarity scale model of a large wind turbine blade, the blade displacement, acceleration, torque and other data can be obtained by implementing the test through the scheme, which is convenient for subsequent comparison with simulation analysis. The present invention solves the problem of the arrangement of the device and the arrangement of the collection equipment of the flutter test platform of the rotating blade. The whole set of processes has been actually tested, and the operation is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0007] Figure 2 It is a sensor arrangement diagram of the present invention.

[0008] In the figure: 1. blade, 2. slip ring, 3. torque meter, 4. electrode, 4a, motor shaft, 5. support frame, 6. bearing, 7. mounting platform, 8. hub, 9. slip ring rotor, 10. slip ring stator, 11. strain gauge, 12. acceleration sensor. DETAILED DESCRIPTION

[0009] The present invention is described below with reference to the accompanying drawings and specific embodiments: Figure 1-2 The overall structure of the present invention is shown. The motor 4, bearing 6 and slip ring 2 are arranged on the mounting platform 7. The support frame 5 is arranged at the bottom of the mounting platform 7. The motor 4 drives the motor shaft 4a, which is supported by the bearing 6. The root joint of the blade 1 is cylindrical, which is convenient for adjusting the pitch angle. The hub 8 connects the blade 1 and the motor shaft 4a. The slip ring 2 is installed between the hub 8 and the motor shaft 4a. The torque meter 3 is installed on the motor shaft 4a after the slip ring 2. The motor 4 is installed behind the torque meter 3 along the airflow direction. The elastic similarity model of the large flexible blade is designed using the scaled theory. The acceleration sensor is installed at the trailing edge of the blade tip of the model, and the strain gauge is installed near the blade tip at the same time. The root joint of the scaled model is designed to be cylindrical, which is convenient for adjusting the pitch angle. The hub connects the model and the platform shaft, and the shaft is connected to the support platform through the bearing. The model strain gauge collects signals using wireless transmission equipment to transmit signals, and the equipment is installed on the hub. A slip ring is installed between the hub and the support platform to transmit acceleration signals. The slip ring rotor is connected to the shaft with set screws, and the stator is connected to the support platform with bolts. The torque meter is installed on the support platform after the slip ring and connected in series to the shaft to measure the real-time torque of the wind turbine.

[0010] A wind tunnel flutter test method for an elastic scaled model of a wind turbine blade in a rotating state comprises the following steps: S1. Using the scaling theory to design an elastic similarity model of a large flexible blade, an acceleration sensor 14 is installed at the trailing edge of the blade tip of the model blade 1, and a strain gauge 13 is installed at the blade web near the blade tip; S2. A dynamic measurement system is arranged at the wind tunnel outlet to measure the displacement response of the model operation; S3. The strain gauge 13 on the blade 1 collects signals and transmits the signals using a wireless transmission device, which is mounted on the hub 8; S4. A slip ring 2 is installed between the hub 8 and the motor shaft 4a for transmitting acceleration signals; the motor shaft 4a passes through the slip ring 2, and the slip ring stator 10 is connected to the slip ring rotor 9, and the slip ring stator 10 is connected to the mounting platform 7 by bolts, and the acceleration signal is transmitted using the slip ring; S5. The torque meter 3 is installed on the motor shaft 4a after the slip ring 2 to measure the real-time torque of the wind turbine; S6. Install motor 4 behind torque meter 3 along the airflow direction, and directly force the speed to be out of the critical speed when flutter occurs. The high-speed servo motor controls the speed, and when flutter occurs, the speed can be directly forced to be out of the critical speed to prevent damage to the wind tunnel.

[0011] During the test, the pitch angle was adjusted. When the wind speed stabilized, a high-speed servo motor was used to control the blade rotation speed to achieve different tip speed ratios during operation. Dynamic measurement technology was used to measure the blade displacement, and a torque meter was used to measure the torque of the blade during operation. The blade scaling theory was used to design the blade model, and acceleration sensors and strain gauges were installed inside to collect the acceleration response and model strain during operation in real time. Finally, the data obtained was post-processed and compared with the simulation values.

[0012] Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wind tunnel flutter test method for an elastic scaled model of a wind turbine blade in a rotating state, characterized in that: The following steps are involved: S1. Using the scaling theory to design an elastic similarity model of a large flexible blade, an acceleration sensor (14) is installed at the trailing edge of the blade tip of the model blade (1), and a strain gauge (13) is installed at the blade web near the blade tip; S2. The motor (4), the bearing (6) and the slip ring (2) are arranged on the mounting platform (7), and a support frame (5) is arranged at the bottom of the mounting platform (7); the motor (4) drives the motor shaft (4a), and the motor shaft (4a) is supported by the bearing (6); the root joint of the blade (1) is cylindrical, which is convenient for adjusting the pitch angle, and the hub (8) connects the blade (1) and the motor shaft (4a); S3. A dynamic measurement system is arranged at the wind tunnel outlet to measure the displacement response of the model operation; S4. The strain gauge (13) on the blade (1) collects the signal and transmits the signal using a wireless transmission device, the wireless transmission device being mounted on the hub (8); S5. A slip ring (2) is installed between the wheel hub (8) and the motor shaft (4a) for transmitting an acceleration signal; the motor shaft (4a) passes through the slip ring (2) and is connected to the slip ring stator (10) and the slip ring rotor (9); the slip ring stator (10) and the mounting platform (7) are connected by bolts, and the acceleration signal is transmitted using the slip ring; S6. The torque meter (3) is installed on the motor shaft (4a) after the slip ring (2) to measure the real-time torque of the wind turbine; S7. A motor (4) is installed behind the torque meter (3) along the airflow direction, and when flutter occurs, the speed is directly forced to be controlled away from the flutter critical speed.

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