DIC-PIV-based wind turbine blade fluid-solid coupling test system and method

Abstract

The invention provides a DIC-PIV-based wind turbine blade fluid-solid coupling test system and method, and relates to the technical field of wind power generation equipment testing, and the system comprises a wind turbine with a speckle pattern layer on the blade surface; the wind tunnel corresponds to the wind turbine and is used for forming a flow field with tracer particles and driving the blades to rotate for power generation; the PIV testing mechanism is used for measuring the motion trail of tracer particles in the flow field; the DIC high-speed camera is used for collecting speckle layer images on the surface of the blade; and the computer can calculate the deformation and position of the blade and the speed distribution of the flow field according to the motion trail of the tracer particles in the flow field and the speckle layer image on the surface of the blade. Two technologies of DIC and PIV are combined, synchronous measurement of blade deformation, blade displacement and flow field speed is realized by utilizing a DIC high-speed camera, a PIV camera and an image processing algorithm in a computer, precise capture of tiny blade deformation and tiny flow field change is realized, and the test efficiency, the test comprehensiveness and the test accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation equipment testing, and in particular to a fluid-solid coupling testing system and method for wind turbine blades based on DIC-PIV. Background Art

[0002] As the global demand for renewable energy continues to grow, wind power generation, as a clean and renewable energy form, is becoming increasingly important. As a key component of a wind turbine, the aerodynamic performance and structural strength of wind turbine blades directly affect the overall efficiency and operational stability of the wind turbine.

[0003] During the operation of wind turbines, wind turbine blades are not only subjected to complex and changeable wind loads, but also need to withstand the influence of their own structural deformation, vibration and environmental factors. This fluid-solid coupling phenomenon under the coupling of multiple physical fields has a significant impact on the aerodynamic performance, structural strength and fatigue life of the blades. With the rapid development of wind power technology, the size of wind turbine blades continues to increase, and their working environment is becoming increasingly complex, especially for wind turbines in coastal areas and typhoon-prone areas, which need to withstand extreme wind conditions. Therefore, accurate and comprehensive testing and analysis of the fluid-solid coupling characteristics of wind turbine blades in complex physical fields is of great significance for improving the overall performance of wind turbines, optimizing blade design and extending service life.

[0004] Traditional wind turbine blade testing methods mainly include finite element simulation and wind tunnel testing. Although finite element simulation has the advantages of low cost and high efficiency, the accuracy of its results is highly dependent on the accuracy of the model and the setting of boundary conditions. Wind tunnel testing focuses on the analysis of a single physical field, that is, separately monitoring the impact of the structural field and flow field on the wind turbine. The cycle is long and it is difficult to fully reveal the fluid-solid coupling characteristics of wind turbine blades in complex physical fields.

[0005] In recent years, with the rapid development of optical measurement technology and computer image processing technology, non-contact measurement technologies such as DIC (digital image correlation) and PIV (particle image velocimetry) have been gradually applied to the testing of wind turbine blades. DIC technology uses image processing algorithms to calculate the deformation and displacement of blades by taking speckle images on the surface of blades, and has the characteristics of high precision and high sensitivity. PIV technology measures the motion trajectory of tracer particles in the flow field and calculates the velocity distribution of the flow field, which can intuitively display the dynamic changes of the flow field. If DIC and PIV technologies are combined, the synchronous measurement of wind turbine blade deformation and flow field velocity can be achieved, providing a new way to fully reveal the fluid-solid coupling characteristics between blades and flow fields. However, there is no mature wind turbine blade fluid-solid coupling test system based on DIC-PIV technology on the market.

[0006] In view of this, how to provide an efficient, accurate and comprehensive wind turbine blade fluid-solid coupling testing system based on DIC-PIV technology is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] The purpose of the present invention is to provide a fluid-solid coupling testing system and method for wind turbine blades based on DIC-PIV to solve the problems existing in the prior art.

[0008] To achieve the above object, the present invention provides the following solution: The present invention provides a fluid-solid coupling testing system for wind turbine blades based on DIC-PIV, comprising:

[0009] A wind turbine having a blade, wherein a surface of the blade has a speckle layer;

[0010] A wind tunnel, the wind outlet of which corresponds to the wind turbine, is used to form a flow field with tracer particles and drive the blades to rotate and generate electricity;

[0011] PIV test mechanism, used to measure the trajectory of tracer particles in the flow field;

[0012] DIC high-speed camera, used to collect speckle layer images on the blade surface;

[0013] A computer is electrically connected to the PIV testing mechanism and the DIC high-speed camera, and the computer can calculate the deformation and position of the blade and the velocity distribution of the flow field according to the motion trajectory of the tracer particles in the flow field and the speckle layer image on the surface of the blade.

[0014] Furthermore, the PIV testing mechanism includes: a PIV camera and a PIV laser fixedly arranged on a dynamic platform; the dynamic platform is used to drive the PIV camera and the PIV laser to move in a horizontal direction, the PIV camera and the PIV laser both correspond to the wind turbine, and the PIV camera and the PIV laser are both electrically connected to a computer; the computer can adjust the output power of the PIV laser through a load control device and a power adjustment device, and record the output power of the PIV laser; the computer can adjust the output power of the wind turbine through a load control device and a power adjustment device, and record the output power of the wind turbine.

[0015] Furthermore, the PIV camera is fixedly mounted on the dynamic platform via a camera fixing platform, and the PIV laser is fixedly mounted on the dynamic platform via a laser fixing platform.

[0016] Furthermore, the dynamic platform is driven by an intelligent magnetic drive module.

[0017] Furthermore, it also includes a light source, which corresponds to the wind turbine; the DIC high-speed camera is installed on a tripod, and the light source is installed on a fixing frame.

[0018] The present invention also provides a fluid-solid coupling testing method for wind turbine blades based on DIC-PIV, comprising the following steps:

[0019] S1: Spraying a speckle layer on the surface of the wind turbine blades, and installing the wind turbine at a position corresponding to the wind tunnel outlet;

[0020] S2: Start the DIC high-speed camera, PIV camera and PIV laser, use the PIV camera to collect the motion trajectory of the tracer particles in the flow field, and use the DIC high-speed camera to collect the speckle layer image on the blade surface;

[0021] S3: Processing the motion trajectory of the tracer particles in the flow field collected in S2 and the speckle layer image on the blade surface by computer, and calculating the deformation and displacement of the blade and the velocity distribution of the flow field;

[0022] S4: Evaluate the aerodynamic performance and structural strength of the blade based on the deformation and displacement of the blade and the velocity distribution of the flow field calculated in S3.

[0023] The present invention discloses the following technical effects:

[0024] The present invention combines DIC and PIV technologies, and utilizes a DIC high-speed camera, a PIV camera, and an image processing algorithm inside a computer to achieve synchronous measurement of blade deformation, blade displacement, and flow field velocity, thereby achieving accurate capture of tiny blade deformations and subtle changes in the flow field, and improving test efficiency, comprehensiveness, and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a structural layout diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the PIV camera installation;

[0028] Figure 3 This is a schematic diagram of the PIV laser installation;

[0029] Figure 4 This is a schematic diagram of the installation of a DIC high-speed camera;

[0030] Figure 5 This is a schematic diagram of light source installation;

[0031] Among them, 1. light source; 2. PIV camera; 3. DIC high-speed camera; 4. PIV laser; 5. blades; 6. generator; 7. wind tunnel; 8. power regulation equipment; 9. computer; 10. dynamic platform; 11. bracket; 12. laser fixing platform; 13. camera fixing platform; 14. intelligent magnetic drive module; 15. tripod; 16. fixing frame. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The embodiment of the present invention provides a fluid-solid coupling test system for wind turbine blades based on DIC-PIV, comprising: a wind turbine having a blade 5, the surface of which has a speckle layer; a wind tunnel 7, the outlet end of which corresponds to the wind turbine, and is used to form a flow field with tracer particles and drive the blade 5 to rotate and generate electricity; specifically, the wind turbine comprises blades 5, a tower and a generator 6, the top of the tower is connected to the generator 6, and the blade 5 is connected to the generator 6 through a flange. The wind tunnel 7 is composed of a motor, a stable section, a contraction section, a closed test section and a diffuser section to ensure that the airflow velocity is stable and uniform after running for a period of time. The center of the wind turbine hub is at the same height as the center of the diffuser section of the wind tunnel 7, and is fixed to the ground with anchor bolts to ensure the safe and stable operation of the wind turbine. The PIV testing mechanism is used to measure the motion trajectory of the tracer particles in the flow field; the DIC high-speed camera 3 is used to collect the speckle layer image on the surface of the blade 5; the computer 9 is electrically connected to the PIV testing mechanism and the DIC high-speed camera 3, and the computer 9 can calculate the deformation and position of the blade 5 and the velocity distribution of the flow field according to the motion trajectory of the tracer particles in the flow field and the speckle layer image on the surface of the blade 5.

[0035] In this embodiment, the PIV test mechanism includes: a PIV camera 2 and a PIV laser 4 fixedly arranged on a dynamic platform 10; the PIV camera 2 is fixedly mounted on the dynamic platform 10 through a camera fixing platform 13, the PIV laser 4 is mounted on a laser fixing platform 12 through a bracket 11, and the laser fixing platform 12 is fixedly mounted on the dynamic platform 10. The dynamic platform 10 is annular and driven by an intelligent magnetic drive module 14, which is used to drive the PIV camera 2 and the PIV laser 4 to move in the horizontal direction (x, y axis), the PIV camera 2 and the PIV laser 4 both correspond to the wind turbine, and the PIV camera 2 and the PIV laser 4 are both electrically connected to a computer 9; the computer 9 can adjust the output power of the PIV laser 4 through a load control device and a power adjustment device 8, and record the output power of the PIV laser 4; the computer 9 can adjust the output power of the wind turbine through a load control device and a power adjustment device 8, and record the output power of the wind turbine. Specifically, the load control device is a DC adjustable load control device, and the power adjustment device 8 is a power analyzer. The PIV camera 2 and the PIV laser 4 are powered by a PIV power supply.

[0036] In this embodiment, a light source 1 is also included, and the light source 1 corresponds to the wind turbine; the DIC high-speed camera 3 is mounted on a tripod 15, and the light source 1 is mounted on a fixing frame 16. The function of the light source 1 is to provide supplementary light according to different lighting conditions, so that the wind turbine test process has sufficient light, and the speckle layer image on the blade 5 can be cleaned and captured.

[0037] The fluid-structure coupling test method for wind turbine blade 5 based on DIC-PIV specifically includes the following steps:

[0038] S1: Spray a speckle layer on the surface of the wind turbine blade 5, install the wind turbine at a position corresponding to the wind outlet of the wind tunnel 7, set appropriate wind speed and wind direction, and prepare to start the test;

[0039] S2: Calibrate the DIC high-speed camera 3. There are two groups of DIC high-speed cameras 3. Use Zhang Zhengyou's calibration method to calibrate the DIC high-speed camera 3. Hold up the calibration plate and align the target surface of the characteristic points on the calibration plate with the DIC high-speed camera 3 to ensure that a clear image is captured. Calibrate and calibrate the PIV camera 2 to ensure that a clear image is captured. Start the DIC high-speed camera 3, PIV camera 2 and PIV laser 4. Use the PIV camera 2 to collect the motion trajectory of the tracer particles in the flow field, and use the DIC high-speed camera 3 to collect the speckle layer image on the surface of the blade 5;

[0040] S3: The computer 9 calculates the deformation and displacement of the blade 5 by combining the motion trajectory of the tracer particles in the flow field with the DIC algorithm, and calculates the velocity distribution of the flow field by combining the speckle layer image on the surface of the blade 5 with the image processing technology;

[0041] S4: The computer 9 collects and fuses the deformation and displacement data of the blade 5 and the velocity distribution data of the flow field, analyzes the interaction mechanism between the blade 5 and the flow field, and evaluates the aerodynamic performance and structural strength of the blade 5.

[0042] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0043] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A fluid-solid coupling test system for wind turbine blades based on DIC-PIV, characterized in that: include: A wind turbine having a blade (5), wherein the surface of the blade (5) has a speckle layer; A wind tunnel (7), the wind outlet of which corresponds to the wind turbine, is used to form a flow field with tracer particles and drive the blades (5) to rotate and generate electricity; PIV test mechanism, used to measure the trajectory of tracer particles in the flow field; A DIC high-speed camera (3) is used to collect a speckle layer image on the surface of the blade (5); A computer (9) is electrically connected to the PIV testing mechanism and the DIC high-speed camera (3), and the computer (9) is capable of calculating the deformation and position of the blade (5) and the velocity distribution of the flow field according to the motion trajectory of the tracer particles in the flow field and the speckle layer image on the surface of the blade (5).

2. A DIC-PIV wind turbine blade fluid-solid coupling testing system according to claim 1, characterized in that: The PIV testing mechanism comprises: a PIV camera (2) and a PIV laser (4) fixedly arranged on a dynamic platform (10); the dynamic platform (10) is used to drive the PIV camera (2) and the PIV laser (4) to move in a horizontal direction, the PIV camera (2) and the PIV laser (4) both correspond to the wind turbine, and the PIV camera (2) and the PIV laser (4) are both electrically connected to a computer (9); the computer (9) can adjust the output power of the PIV laser (4) through a load control device and a power adjustment device (8), and record the output power of the PIV laser (4); the computer (9) can adjust the output power of the wind turbine through the load control device and the power adjustment device (8), and record the output power of the wind turbine.

3. The DIC-PIV wind turbine blade fluid-solid coupling test system according to claim 2, characterized in that: The PIV camera (2) is fixedly mounted on the dynamic platform (10) via a camera fixing platform (13), and the PIV laser (4) is fixedly mounted on the dynamic platform (10) via a laser fixing platform (12).

4. The DIC-PIV wind turbine blade fluid-solid coupling test system according to claim 2, characterized in that: The dynamic platform (10) is driven by an intelligent magnetic drive module (14).

5. The DIC-PIV wind turbine blade fluid-solid coupling testing system according to claim 1, characterized in that: It also comprises a light source (1), the light source (1) corresponding to the wind turbine; the DIC high-speed camera (3) is mounted on a tripod (15), and the light source (1) is mounted on a fixing frame (16).

6. A fluid-solid coupling testing method for wind turbine blades based on DIC-PIV, characterized in that: The following steps are involved: S1: spraying a speckle layer on the surface of a wind turbine blade (5), and installing the wind turbine at a position corresponding to the wind outlet end of a wind tunnel (7); S2: Start the DIC high-speed camera (3), the PIV camera (2) and the PIV laser (4), use the PIV camera (2) to collect the motion trajectory of the tracer particles in the flow field, and use the DIC high-speed camera (3) to collect the speckle layer image on the surface of the blade (5); S3: Processing the motion trajectory of the tracer particles in the flow field collected in S2 and the speckle layer image on the surface of the blade (5) by a computer (9), and calculating the deformation and displacement of the blade (5) and the velocity distribution of the flow field; S4: Evaluate the aerodynamic performance and structural strength of the blade (5) based on the deformation and displacement of the blade (5) and the velocity distribution results of the flow field calculated in S3.

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