Visual testing method and device for vortex-induced wake flow of fan based on optical flow method theory

Abstract

The invention discloses a fan vortex-induced wake flow visualization test method and device based on an optical flow method theory, and the method comprises the steps: arranging at least three wireless smoke sprayers along the wall of a fan tower at different heights; acquiring colored smoke spraying images of the wireless smoke sprayers at different heights under various wind conditions by using image acquisition equipment, and synchronously acquiring unit state information at corresponding moments and elevation angle and focal length parameters of the image acquisition equipment; a vortex-induced wake flow visualization model is constructed; constructing a vortex-induced wake flow characteristic model based on an optical flow method; and utilizing the vortex-induced wake flow characteristic model to obtain the wake flow condition when the fan is subjected to vortex-induced. According to the method, colored smoke spraying images of wireless smoke sprayers at different heights under various wind conditions are obtained, a vortex-induced wake flow visual model is generated according to the images, the vortex-induced wake flow visual model is analyzed on the basis of an optical flow method, and a vortex-induced wake flow characteristic model is established, so that the wake flow condition during vortex excitation of the fan is conveniently obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine vortex-induced monitoring, and in particular to a visualization test method and device for wind turbine vortex-induced wake based on the optical flow method theory. Background Art

[0002] Wind turbine vortex-induced refers to the situation where when the tower barrel of a wind turbine is hoisted or the nacelle is hoisted and the unit is not powered on after hoisting, the unit cannot yaw and pitch to the wind, causing the wind to alternately separate from the surface of the tower barrel on both sides of the unit to generate vortices. These vortices will cause the tower barrel and blades to vibrate periodically, and this regular column vibration will in turn change the vortex shedding pattern of its wake. When the vibration is coupled with the natural frequencies of the tower barrel, blades, etc., resonance vibration will occur, which is the wind turbine vortex-induced.

[0003] At present, there are many methods for suppressing wind turbine vortex-induced vibration, but there are few visualization monitoring methods for wake vortices during actual vortex-induced monitoring. There is only simulation calculation, and there is almost no on-site actual monitoring. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a visualization test method for wind turbine vortex-induced wake based on the optical flow method theory. By obtaining the colored smoke ejection images of wireless smoke sprayers at different heights under various wind conditions, generating a vortex-induced wake visualization model according to the images, analyzing the vortex-induced wake visualization model based on the optical flow method, and establishing a vortex-induced wake characteristic model, so as to obtain the wake situation during wind turbine vortex-induced.

[0005] Another purpose of the present invention is to provide a visualization test device for wind turbine vortex-induced wake based on the optical flow method theory.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A visualization test method for wind turbine vortex-induced wake based on the optical flow method theory includes the steps of,

[0008] Arrange at least three wireless smoke sprayers at different heights along the wall of the wind turbine tower barrel;

[0009] Use an image acquisition device to obtain the colored smoke ejection images of wireless smoke sprayers at different heights under various wind conditions, and synchronously obtain the unit status information and the elevation angle and focal length parameters of the image acquisition device at the corresponding moment;

[0010] Construct a vortex-induced wake visualization model according to the colored smoke ejection images, unit status information, and elevation angle and focal length parameters;

[0011] Construct a vortex-induced wake characteristic model based on the optical flow method according to the vortex-induced wake visualization model;

[0012] Obtain the wake situation of the wind turbine during vortex-induced vibration using the vortex-induced wake characteristic model.

[0013] Furthermore, the image acquisition device is a large-field-of-view auto-focus camera, which is set on the ground by a tripod and is located beside the wind turbine tower. This auto-focus camera can take static images with 12 million pixels, the frame rate is greater than or equal to 5 fps, the working distance of the lens is greater than or equal to 400 m, the measurement range meets 100 m * 50 m, and the single test time is one minute.

[0014] Furthermore, use the image acquisition device to obtain the colored smoke ejection images of the wireless smoke injectors at different heights under various wind conditions, and synchronously obtain the unit status information and the elevation angle and focal length parameters of the image acquisition device at the corresponding moments. Specifically, perform the following operations:

[0015] Trigger the wireless smoke injectors in sequence. After the colored smoke is ejected, trigger the image acquisition device to obtain the colored smoke ejection images of the wireless smoke injectors at different heights under various wind conditions, and synchronously obtain the unit status information and the elevation angle and focal length parameters of the image acquisition device at the corresponding moments; each time the image acquisition device is triggered, it can automatically take 300 images in total for 1 minute and transmit them back to the collector. The collector automatically obtains the unit status information by reading the IP; trigger different wireless smoke injectors at different heights in sequence to obtain different results.

[0016] Furthermore, the unit status information includes the wind speed and wind direction of the nacelle.

[0017] Furthermore, according to the colored smoke ejection images, the unit status information, and the elevation angle and focal length parameters, construct a vortex-induced wake visualization model. Specifically, perform the following operations:

[0018] Input the elevation angle and focal length into the analysis software to obtain the distances of each position on the field of view, import the colored smoke ejection images, and generate a vortex-induced wake visualization model.

[0019] Furthermore, according to the vortex-induced wake visualization model, construct a vortex-induced wake characteristic model based on the optical flow method. Specifically, perform the following operations:

[0020] According to the vortex-induced wake visualization model, compare and analyze all the colored smoke ejection images, generate a vortex-induced wake dynamic visualization model, extract the area and diffusion speed of the smoke diffusion, that is, the eddy area and eddy current velocity, and establish the diffusion relationship of the eddy current during the vortex-induced vibration of the wind turbine based on the optical flow method analysis method, that is, the vortex-induced wake characteristic model.

[0021] Furthermore, the vortex-induced wake characteristic model includes the wake width W (x) , the wake flow velocity V (x) , the wake turbulent kinetic energy TKE (x) , the wake vorticity Z (x) and the wake influence area L.

[0022] Wake width W (x) The formula is:

[0023]

[0024] Wake flow velocity V (x) The formula is:

[0025]

[0026] Turbulent kinetic energy of wake TKE (x) The formula is:

[0027]

[0028] Wake vorticity Z (x) The formula is:

[0029]

[0030] The formula for the wake influence area L is:

[0031]

[0032] Wherein, D is the tower barrel diameter, x is the distance downstream of the tower, k1 is an empirical coefficient, and its value range is 0.1 - 0.3, U is the incoming flow velocity, C d is the drag coefficient of the tower barrel. The tower barrel is a smooth cylinder, C d ≈1.0, ρ is the fluid density, k2 is an empirical coefficient, and its value range is between 5 - 10;

[0033] According to the wake width W (x) 、wake flow velocity V (x) 、turbulent kinetic energy of wake TKE (x) 、wake vorticity Z (x) and the wake influence area L, the wake situation during the vortex-induced vibration of the wind turbine is obtained.

[0034] Another object of the present invention is achieved by the following technical solution:

[0035] A visualization test device for the wind turbine vortex-induced wake based on the optical flow theory, which is applied to the above-mentioned visualization test method for the wind turbine vortex-induced wake based on the optical flow theory, includes a wireless smoke sprayer, an image acquisition device, a tripod, a trigger, a collector and a main control system. There are at least three wireless smoke sprayers, which are arranged at different heights along the wall of the wind turbine tower barrel for spraying colored smoke. The image acquisition device is an automatic zoom camera, which is set on the ground through a tripod and is located beside the wind turbine tower barrel. The trigger is respectively communicatively connected with the wireless smoke sprayer and the image acquisition device for triggering the wireless smoke sprayer and the image acquisition device. The collector is respectively communicatively connected with the image acquisition device and the main control system for receiving the images of the ejected colored smoke and obtaining the unit status information.

[0036] Further, the wireless smoke sprayer includes a high-pressure smoke machine, a thick smoke oil tank, a smoke pipe, a smoke nozzle, a laser, a control module and a power supply module. One end of the high-pressure smoke machine is connected to the thick smoke oil tank, and the other end is connected to the smoke pipe. The smoke pipe is connected to the smoke nozzle, and the smoke nozzle is arranged upward for evenly and highly speedily ejecting the thick smoke generated by the high-pressure smoke machine. The control module is respectively communicatively connected with the high-pressure smoke machine and the laser. The control module is internally provided with a remote infrared control chip, and remotely controls the start and stop of the high-pressure smoke machine and controls the laser to cut the thick smoke through the trigger. The power supply module is electrically connected to the high-pressure smoke machine, the laser and the control module for power supply.

[0037] Further, a plurality of magnet suction cups for adsorbing on the wall of the wind turbine tower barrel are arranged at the bottom of the wireless smoke sprayer.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. The present invention can clearly determine the wake generation process during the vortex-induced vibration of the wind turbine under various working conditions, and through the comparative analysis of multiple groups of photos, obtain relevant coefficients to establish the diffusion relationship of the eddy current during the vortex-induced vibration of the wind turbine, and establish a characteristic model of the vortex-induced wake, which is more appropriate for the wake situation during the vortex-induced vibration of the wind turbine than the results calculated by the simulation software, and provides measured data for the wind power industry's understanding of the vortex-induced vibration of the unit.

[0040] 2. The test method of the present invention is simple to operate and can be reused for multiple projects. Description of the Drawings

[0041] Figure 1 It is the method flow chart of the present invention.

[0042] Figure 2 It is the structural schematic diagram of the test device of the present invention.

[0043] Figure 3 It is the partial schematic diagram of the test device of the present invention.

[0044] Figure 4 This is the front view of the wireless smoke sprayer of the present invention.

[0045] Figure 5 This is the top view of the wireless smoke sprayer of the present invention.

[0046] Figure 6 This is the left view of the wireless smoke sprayer of the present invention.

[0047] Figure 7 This is the schematic diagram of the test device of the present invention. Detailed implementation manners

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1:

[0050] As Figure 1 shown, this embodiment provides a visualization test method for the wake of a wind turbine based on the optical flow theory, including the steps of

[0051] S1. Arrange at least three portable wireless smoke sprayers at different heights along the wall of the wind turbine tower.

[0052] S2. Use an image acquisition device to obtain the colored smoke ejection images of the wireless smoke sprayers at different heights under various wind conditions, and synchronously obtain the unit status information and the elevation angle and focal length parameters of the image acquisition device at the corresponding moments. The specific operations are as follows:

[0053] Trigger the wireless smoke sprayers in sequence. After the colored smoke is ejected, trigger the image acquisition device to obtain the colored smoke ejection images of the wireless smoke sprayers at different heights under various wind conditions, and synchronously obtain the unit status information and the elevation angle and focal length parameters of the image acquisition device at the corresponding moments. Each time the image acquisition device is triggered, it can automatically take 300 photos in total for 1 minute and send them back to the collector. The collector automatically obtains the unit status information by reading the IP. Different results are obtained by triggering the wireless smoke sprayers at different heights in sequence.

[0054] Among them, the image acquisition device is an auto-focus camera, which is set on the ground by a tripod and located beside the wind turbine tower barrel. The auto-focus camera can take static images with 12 million pixels, the frame rate is greater than or equal to 5 fps, the working distance of the lens is greater than or equal to 400 m, the measurement range meets 100 m * 50 m, the single test time is one minute, taking the frame rate equal to 5 fps as an example, the camera should be able to automatically and continuously acquire 300 pictures when triggered once;

[0055] The unit status information includes the wind speed and direction in the nacelle.

[0056] S3. According to the colored smoke ejection image, the unit status information, and the elevation angle and focal length parameters, construct a vortex-induced wake visualization model; specifically, perform the following operations:

[0057] Input the elevation angle and focal length in the analysis software to obtain the distances of each position on the field of view, import the colored smoke ejection image, and generate a vortex-induced wake visualization model.

[0058] S4. According to the vortex-induced wake visualization model, construct a vortex-induced wake characteristic model based on the optical flow method combined with empirical formulas. Specifically, perform the following operations:

[0059] According to the vortex-induced wake visualization model, compare and analyze 300 pictures at the 0.2-second level, generate a dynamic visualization model of the vortex-induced wake, extract the area and diffusion speed of the smoke diffusion, that is, the vortex area and vortex flow velocity, and establish the diffusion relationship of the vortex during the vortex-induced vibration of the wind turbine based on the optical flow method analysis method, that is, the vortex-induced wake characteristic model.

[0060] Among them, the vortex-induced wake characteristic model includes the wake width W (x) 、the wake flow velocity V (x) 、the wake turbulent kinetic energy TKE (x) 、the wake vorticity Z (x) and the wake influence area L,

[0061] The wake width W (x) The formula is:

[0062]

[0063] The wake flow velocity V (x) The formula is:

[0064]

[0065] The wake turbulent kinetic energy TKE (x) The formula is:

[0066]

[0067] The wake vorticity Z (x) The formula is:

[0068]

[0069] The formula for the wake influence area L is as follows:

[0070]

[0071] Among them, D is the tower barrel diameter, x is the distance downstream of the tower, k1 is an empirical coefficient, and its value range is 0.1 - 0.3, which is related to the flow conditions and the tower shape. U is the incoming flow velocity, C d is the drag coefficient of the tower barrel. The tower barrel is a smooth cylinder, and C d ≈1.0, ρ is the fluid density, and k2 is an empirical coefficient, and its value range is between 5 - 10.

[0072] S5. Obtain the wake situation during the vortex-induced vibration of the wind turbine by using the vortex-induced wake characteristic model, that is, according to the wake width W (x) and the wake flow velocity V (x) and the wake turbulent kinetic energy TKE (x) and the wake vorticity Z (x) and the wake influence area L to obtain the wake situation during the vortex-induced vibration of the wind turbine.

[0073] Example 2:

[0074] As Figures 2 to 7 shown, this embodiment provides a visual test device for the vortex-induced wake of a wind turbine based on the optical flow method theory, which is applied to the visual test method for the vortex-induced wake of a wind turbine based on the optical flow method theory in Example 1. It includes a wireless smoke sprayer 1, an image acquisition device 2, a tripod 3, a trigger 4, a collector 5, and a main control system. There are at least three wireless smoke sprayers 1, which are arranged at different heights along the wall of the wind turbine tower barrel for spraying colored smoke. The image acquisition device 2 is a large-field-of-view automatic zoom camera, which is set on the ground through the tripod 3 and is located beside the wind turbine tower barrel. The tripod 3 is an adjustable tripod 3, with the lowest height less than 0.35 m and the load-bearing greater than or equal to 25 kg. The trigger 4 is respectively communicatively connected to the wireless smoke sprayer 1 and the image acquisition device 2 for triggering the wireless smoke sprayer 1 and the image acquisition device 2. The collector 5 is respectively communicatively connected to the image acquisition device 2 and the main control system for receiving the image of the colored smoke ejected and obtaining the unit status information.

[0075] The wireless smoke sprayer 1 includes a high-pressure smoke machine 101, a thick smoke oil tank 102, a smoke pipe 103, a smoke nozzle 104, a laser 105, a control module 106 and a power module 107. One end of the high-pressure smoke machine 101 is connected to the thick smoke oil tank 102, and the other end is connected to the smoke pipe 103. The smoke pipe 103 is connected to the smoke nozzle 104, and the smoke nozzle 104 is arranged upward to evenly and highly speedily spray the thick smoke generated by the high-pressure smoke machine 101 to reduce the influence of gravity diffusion of the smoke. The control module 106 is respectively connected to the high-pressure smoke machine 101 and the laser 105 through a signal line 108. The control module 106 is internally provided with a remote infrared control chip, and remotely controls the start and stop of the high-pressure smoke machine 101 and controls the laser 105 to cut the thick smoke through a trigger 4. The power module 107 is connected to the high-pressure smoke machine 101, the laser 105 and the control module 106 through a power line 109 for power supply.

[0076] For the convenience of installation, a plurality of magnet suction cups 110 for adsorbing on the wall of the fan tower barrel are arranged at the bottom of the wireless smoke sprayer 1, and the outer shell material of the wireless smoke sprayer 1 is iron.

[0077] The power module 107 is a rechargeable UPS power supply, and the power capacity should at least meet 1 kWh. The signal line 108 and the power line 109 should have anti-interference outer shells, and both ends adopt the form of aviation plugs.

[0078] As mentioned above, it is only a preferred embodiment of the present invention patent, but the protection scope of the present invention patent is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention patent, according to the technical solution of the present invention patent and the inventive concept of the present invention patent, makes equivalent replacements or changes, and all belong to the protection scope of the present invention patent.

Claims

1. A visual test method for fan vortex wake based on optical flow theory, characterized in that: Including steps, At least three wireless smoke emitters are arranged at different heights along the wall of the wind turbine tower; Use image acquisition equipment to obtain colored smoke emission images of wireless smoke emitters at different heights under various wind conditions, and simultaneously obtain the unit status information at the corresponding moment and the elevation angle and focal length parameters of the image acquisition equipment; A vortex wake visualization model is constructed based on the colored smoke emission image, unit status information, and elevation angle and focal length parameters; According to the vortex wake visualization model, the vortex wake characteristic model is constructed based on the optical flow method; The vortex-induced wake characteristic model is used to obtain the wake conditions of the fan when vortex is excited.

2. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: The image acquisition device is an automatic zoom camera, which is set on the ground by a tripod and located next to the wind turbine tower. The automatic zoom camera meets the requirements of 12-megapixel static image shooting, the frame rate is greater than or equal to 5fps, the lens working distance is greater than or equal to 400m, the measurement range meets 100m*50m, and the single test time is one minute.

3. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: Use the image acquisition device to obtain the colored smoke emission images of the wireless smoke emitters at different heights under various wind conditions, and synchronously obtain the unit status information at the corresponding moment and the elevation angle and focal length parameters of the image acquisition device. Specifically, perform the following operations: The wireless smoke sprayers are triggered in sequence, and after the colored smoke is sprayed out, the image acquisition device is triggered to obtain the colored smoke spraying images of the wireless smoke sprayers at different heights under various wind conditions, and the unit status information at the corresponding moment and the elevation angle and focal length parameters of the image acquisition device are simultaneously obtained; each time the image acquisition device is triggered, it can automatically take a total of 300 images in 1 minute and send them back to the collector, which automatically obtains the unit status information by reading the IP; the wireless smoke sprayers at different heights are triggered in sequence to collect different results.

4. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: The unit status information includes the wind speed and wind direction in the cabin.

5. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: According to the colored smoke emission image, unit status information, and elevation angle and focal length parameters, a vortex wake visualization model is constructed. The following operations are performed: The elevation angle and focal length are input into the analysis software to obtain the distance of each position in the field of view, and the colored smoke ejection image is imported to generate a visualization model of the vortex wake.

6. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: According to the vortex wake visualization model, the vortex wake characteristic model is constructed based on the optical flow method. The following operations are performed specifically: According to the vortex wake visualization model, all colored smoke ejection images are compared and analyzed to generate a dynamic visualization model of the vortex wake. The smoke diffusion area and diffusion speed, namely the vortex area and vortex velocity, are extracted. Based on the optical flow analysis method, the diffusion relationship of the vortex during fan vortex excitation, namely the vortex wake characteristic model, is established.

7. The wind turbine vortex wake visualization test method based on the optical flow theory according to claim 1 is characterized in that: The vortex wake characteristic model includes the wake width W (x) , wake velocity V (x) 、Take Kinetic Energy TKE (x) , wake vorticity Z (x) and the wake impact area L, Wake width W (x) The formula is: Wake velocity V (x) The formula is: Wake Kinetic Energy TKE (x) The formula is: Wake vorticity Z (x) The formula is: The formula for the wake influence area L is: Where D is the tower diameter, x is the distance from the tower downstream, k1 is the empirical coefficient, the value range is 0.1~0.3, U is the incoming flow velocity, C d is the resistance coefficient of the tower, the tower is a smooth cylinder, C d ≈1.0, ρ is the fluid density, k2 is the empirical coefficient, and the value range is between 5 and 10; According to the wake width W (x) , wake velocity V (x) 、Take Kinetic Energy TKE (x) , wake vorticity Z (x) And the wake influence area L is used to obtain the wake conditions when the fan is vortex-excited.

8. A visual test device for fan vortex wake based on optical flow theory, characterized in that: The wind turbine vortex wake visualization test method based on the optical flow theory as described in any one of claims 1 to 7 includes a wireless smoke sprayer, an image acquisition device, a tripod, a trigger, a collector and a main control system, wherein there are at least three wireless smoke sprayers, which are arranged at different heights along the wall of the wind turbine tower and are used to spray colored smoke. The image acquisition device is an automatic zoom camera, which is set on the ground through a tripod and is located next to the wind turbine tower. The trigger is respectively communicated with the wireless smoke sprayer and the image acquisition device to trigger the wireless smoke sprayer and the image acquisition device. The collector is respectively communicated with the image acquisition device and the main control system to receive the colored smoke spray image and obtain the unit status information.

9. The wind turbine vortex wake visualization test device based on the optical flow theory according to claim 8 is characterized in that: The wireless smoke sprayer includes a high-pressure smoke machine, a thick smoke and fog oil tank, a smoke pipe, a smoke nozzle, a laser, a control module and a power module. One end of the high-pressure smoke machine is connected to the thick smoke and fog oil tank, and the other end is connected to the smoke pipe. The smoke pipe is connected to the smoke nozzle. The smoke nozzle is arranged upward and is used to spray the thick smoke generated by the high-pressure smoke machine evenly and at high speed. The control module is respectively communicated with the high-pressure smoke machine and the laser. The control module has a built-in remote infrared control chip. The trigger is used to remotely control the start and stop of the high-pressure smoke machine and control the laser to cut the thick smoke. The power module is electrically connected to the high-pressure smoke machine, the laser and the control module for power supply.

10. The wind turbine vortex wake visualization test device based on the optical flow theory according to claim 9 is characterized in that: The bottom of the wireless smoke sprayer is provided with a plurality of magnetic suction cups for adsorbing on the wall of the wind turbine tower.

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