A wind turbine blade fluid-structure coupling test system and method based on DIC-PIV

Abstract

The application provides a kind of based on DIC-PIV wind turbine blade fluid-structure coupling test system and method, it is related to wind power generation equipment test technical field, including: wind turbine, its blade surface has speckle layer;Wind tunnel corresponds with wind turbine, for forming with the flow field of tracer particle and driving blade rotation power generation;PIV test mechanism is used to measure the motion trajectory of tracer particle in flow field;DIC high-speed camera is used to collect the speckle layer image of blade surface;Computer can calculate the deformation and position of blade and the velocity distribution of flow field according to the motion trajectory of tracer particle in flow field and the speckle layer image of blade surface.Combining DIC and PIV two technologies, utilize DIC high-speed camera, PIV camera and the image processing algorithm in computer to realize the synchronous measurement of blade deformation, blade displacement and flow field velocity, realize the accurate capture of blade slight deformation and flow field subtle change, improve test efficiency, test comprehensiveness and accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation equipment testing, in particular to a wind turbine blade fluid-structure coupling test system and method based on DIC-PIV. BACKGROUND

[0002] With the continuous growth of global demand for renewable energy, wind power as a clean and renewable energy form has become increasingly important. Wind turbine blades, as the key components of wind turbines, directly affect the overall efficiency and operational stability of the wind turbine.

[0003] During the operation of the wind turbine, the wind turbine blade not only bears complex and variable wind loads, but also needs to withstand its own structural deformation, vibration and environmental factors. The fluid-structure coupling phenomenon under the coupling of multiple physical fields has a significant impact on the aerodynamic performance, structural strength and fatigue life of the blade. With the rapid development of wind power technology, the size of the wind turbine blade is continuously increasing, and its working environment is becoming increasingly complex, especially for wind turbines in coastal and typhoon-prone areas, which need to withstand extreme wind conditions. Therefore, accurately and comprehensively testing and analyzing the fluid-structure coupling characteristics of the wind turbine blade in complex physical fields is of great significance to improving the overall performance of the wind turbine, optimizing the blade design and prolonging the service life.

[0004] Traditional wind turbine blade testing methods mainly include finite element simulation and wind tunnel test. 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 the boundary conditions. Wind tunnel test focuses on the analysis of a single physical field, i.e. separately monitoring the effects of the structural field and the flow field on the wind turbine, which is time-consuming and difficult to fully reveal the fluid-structure coupling characteristics of the wind turbine blade 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 gradually been applied in the testing field of wind turbine blades. DIC technology captures speckle images on the surface of the blade, calculates the deformation and displacement of the blade using image processing algorithms, 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 show the dynamic changes of the flow field. By combining DIC and PIV technologies, synchronous measurement of wind turbine blade deformation and flow field velocity can be achieved, providing a new way to fully reveal the fluid-structure coupling characteristics between the blade and the flow field. However, there is no mature wind turbine blade fluid-structure coupling test system based on DIC-PIV technology on the market.

[0006] Therefore, how to provide an efficient, accurate and comprehensive wind turbine blade fluid-structure coupling test system based on DIC-PIV technology is an urgent problem for those skilled in the art. SUMMARY

[0007] The purpose of the present application is to provide a DIC-PIV wind turbine blade fluid-structure coupling test system and method to solve the problems existing in the prior art.

[0008] To achieve the above-mentioned purpose, the present application provides the following scheme: the present application provides a DIC-PIV wind turbine blade fluid-structure coupling test system, comprising:

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

[0010] A wind tunnel is arranged corresponding to the wind turbine at the air outlet end, used to form a flow field with tracer particles and drive the blade to rotate to generate electricity;

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

[0012] A DIC high-speed camera is used to collect the speckle layer image of the blade surface;

[0013] A computer is electrically connected to the PIV test 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 of the blade surface.

[0014] Further, the PIV test mechanism comprises 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 along the horizontal direction, the PIV camera and the PIV laser are both corresponding to the wind turbine, and the PIV camera and the PIV laser are both electrically connected to the computer; the computer can adjust the output power of the PIV laser through the load control device and the power adjustment device, and record the output power of the PIV laser; the computer can adjust the output power of the wind turbine through the load control device and the power adjustment device, and record the output power of the wind turbine.

[0015] Further, the PIV camera is fixedly installed on the dynamic platform through a camera fixing platform, and the PIV laser is fixedly installed on the dynamic platform through a laser fixing platform.

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

[0017] Further, the light source corresponding to the wind turbine is further included; the DIC high-speed camera is installed on a tripod, and the light source is installed on a fixed frame.

[0018] The application further provides a DIC-PIV wind turbine blade fluid-structure coupling test method.

[0019] S1: a speckle layer is sprayed on the surface of the blade of the wind turbine, and the wind turbine is installed at a position corresponding to the outflow end of the wind tunnel;

[0020] S2: the DIC high-speed camera, the PIV camera and the PIV laser are started, the motion track of the tracer particle in the flow field is collected by the PIV camera, and the speckle layer image of the blade surface is collected by the DIC high-speed camera;

[0021] S3: the motion track of the tracer particle in the flow field and the speckle layer image of the blade surface collected in S2 are processed by a computer, and the deformation and displacement of the blade and the velocity distribution of the flow field are calculated;

[0022] S4: the aerodynamic performance and the structural strength of the blade are evaluated according to the results of the deformation and displacement of the blade and the velocity distribution of the flow field calculated in S3.

[0023] The application discloses the following technical effects:

[0024] The application combines the DIC and PIV technologies, and realizes the synchronous measurement of the blade deformation, the blade displacement and the flow field velocity by using the DIC high-speed camera, the PIV camera and the image processing algorithm in the computer, so that the accurate capture of the small deformation of the blade and the slight change of the flow field is realized, and the test efficiency, the comprehensiveness and the accuracy of the test are improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0026] Figure 1 It is a structural arrangement drawing of the application;

[0027] Figure 2 It is a PIV camera installation schematic diagram;

[0028] Figure 3 It is a PIV laser installation schematic diagram;

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

[0030] Figure 5 Schematic diagram for installing light source;

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

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with the drawings and specific embodiments.

[0034] The embodiment of the present application provides a DIC-PIV wind turbine blade fluid-structure coupling test system, which comprises: a wind turbine having a blade 5, the surface of the blade 5 having a speckle layer; a wind tunnel 7 corresponding to the wind turbine at the air outlet end, used for forming a flow field with tracer particles and driving the blade 5 to rotate and generate electricity; specifically, the wind turbine comprises the blade 5, a tower and a generator 6, the top of the tower is connected with the generator 6, and the blade 5 is connected with 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, so as to ensure that the flow velocity is stable and uniform after running for a period of time. The center of the hub of the wind turbine is at the same height as the center of the diffuser section of the wind tunnel 7, and is fixed on the ground by anchor bolts, so as to ensure that the wind turbine runs safely and stably. A PIV test mechanism is used for measuring the motion trajectory of the tracer particles in the flow field; a DIC high-speed camera 3 is used for collecting the speckle layer image of the surface of the blade 5; a computer 9 is electrically connected with the PIV test 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 of the surface of the blade 5.

[0035] In the embodiment, the PIV testing mechanism comprises: a PIV camera 2 and a PIV laser 4 fixedly arranged on a dynamic platform 10; the PIV camera 2 is fixedly installed on the dynamic platform 10 through a camera fixing platform 13, and the PIV laser 4 is installed on a laser fixing platform 12 through a support 11, and the laser fixing platform 12 is fixedly installed on the dynamic platform 10. The dynamic platform 10 is annular, is driven by an intelligent magnetic drive module 14, and is used to drive the PIV camera 2 and the PIV laser 4 to move in a horizontal direction (x, y axes), the PIV camera 2 and the PIV laser 4 correspond to the wind turbine, and the PIV camera 2 and the PIV laser 4 are electrically connected with a computer 9; the computer 9 can adjust the output power of the PIV laser 4 through a load control device and a power adjusting 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 adjusting device 8, and record the output power of the wind turbine. Specifically, the load control device is a direct-current adjustable load control device, and the power adjusting device 8 is a power analyzer. The PIV camera 2 and the PIV laser 4 are powered by a PIV power supply.

[0036] In the embodiment, a light source 1 is further included, the light source 1 corresponds to the wind turbine; the DIC high-speed camera 3 is installed on a tripod 15, and the light source 1 is installed on a fixing frame 16. The light source 1 is used to supplement light according to different light conditions, so that the wind turbine testing process is sufficient in light, and the speckle layer image on the blade 5 can be captured.

[0037] The DIC-PIV wind turbine blade 5 fluid-structure coupling testing method specifically comprises the following steps:

[0038] S1: a speckle layer is formed by spraying on the surface of the blade 5 of the wind turbine, the wind turbine is installed at a position corresponding to the wind outlet end of the wind tunnel 7, appropriate wind speed and wind direction are set, and the testing is ready to start;

[0039] S2: the DIC high-speed camera 3 is calibrated, there are two groups of DIC high-speed cameras 3, the DIC high-speed camera 3 is calibrated by using Zhang Zhengyou calibration method, the calibration plate is lifted and the target surface of the feature points on the calibration plate is aligned with the DIC high-speed camera 3, and clear images are ensured to be captured. The PIV camera 2 is calibrated and adjusted, and clear images are ensured to be captured. The DIC high-speed camera 3, the PIV camera 2 and the PIV laser 4 are started, the PIV camera 2 is used to collect the motion trajectory of the tracer particles in the flow field, and the DIC high-speed camera 3 is used 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 DIC algorithm with the motion trajectory of the tracer particles in the flow field, 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 application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0043] The above-described embodiments are only descriptions of the preferred modes of the present application and do not limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1.A method for testing fluid-structure interaction of a wind turbine blade based on DIC-PIV, characterized in that, The application discloses a wind turbine blade fluid-structure coupling test system based on DIC-PIV. The wind turbine blade fluid-structure coupling test system based on DIC-PIV comprises the following: A wind turbine has a blade (5) with a speckle pattern layer on the surface of the blade (5); A wind tunnel (7) corresponding to the wind turbine at the air outlet end is used to form a flow field with tracer particles and drive the blade (5) to rotate to generate electricity; A PIV test mechanism is used to measure the motion trajectory of the tracer particles in the flow field; A DIC high-speed camera (3) is used to collect the speckle pattern layer image of the surface of the blade (5); A computer (9) is electrically connected with the PIV test 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 pattern layer image of the surface of the blade (5); The PIV test 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 along the horizontal direction; the PIV camera (2) and the PIV laser (4) are both corresponding to the wind turbine, and the PIV camera (2) and the PIV laser (4) are both electrically connected with the computer (9); the computer (9) can adjust the output power of the PIV laser (4) through a load control device and a power adjusting 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 adjusting device (8), and record the output power of the wind turbine; The PIV camera (2) is fixedly installed on the dynamic platform (10) through a camera fixing platform (13), and the PIV laser (4) is fixedly installed on the dynamic platform (10) through a laser fixing platform (12); the dynamic platform (10) is driven by an intelligent magnetic drive module (14); A light source (1) corresponding to the wind turbine; the DIC high-speed camera (3) is installed on a tripod (15), and the light source (1) is installed on a fixing frame (16); The method comprises the following steps: S1: spraying a speckle pattern layer on the surface of the blade (5) of the wind turbine, and installing the wind turbine at a position corresponding to the air outlet end of the wind tunnel (7); S2: starting the DIC high-speed camera (3), the PIV camera (2) and the PIV laser (4), collecting the motion trajectory of the tracer particles in the flow field by the PIV camera (2), and collecting the speckle pattern layer image of the surface of the blade (5) by the DIC high-speed camera (3); S3: processing the motion trajectory of the tracer particles in the flow field and the speckle pattern layer image of the surface of the blade (5) collected in S2 by the computer (9), calculating the deformation and displacement of the blade (5) and the velocity distribution of the flow field; S4: evaluating the aerodynamic performance and structural strength of the blade (5) according to the results of the deformation and displacement of the blade (5) and the velocity distribution of the flow field calculated in S3.

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