High-speed train wind tunnel test system and method based on PIV particle tracer technology

Abstract

The invention relates to the technical field of wind tunnel tests, in particular to a high-speed train wind tunnel test system and method based on the PIV particle tracer technology, and the test system comprises a wind tunnel housing, a tracer particle emitter, a light curtain assembly, an imaging assembly and a train assembly which is movably installed in the wind tunnel housing. The light curtain assembly is fixed to the bottom of the periphery of the wind tunnel shell, the imaging assembly is located on the side face of the periphery of the wind tunnel shell, the tracer particle emitting device comprises a storage device, a transmission pipeline and a hollow rectification net, the hollow rectification net is fixed to a port of the wind tunnel stabilizing section, the transmission pipeline is connected between the hollow rectification net and the storage device, and the storage device is connected with the imaging assembly. And a plurality of nozzles are arranged on the hollow rectification net in a matrix shape. According to the method, the problem of non-uniform spreading of the tracer particles when flow field velocity distribution is obtained by adopting a PIV technology in a high-speed train wind tunnel test is solved, and the accuracy and the reliability of a test result are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of wind tunnel testing, and in particular to a high-speed train wind tunnel testing system and method based on PIV particle tracing technology. Background Art

[0002] In the design and testing of high-speed trains, wind tunnel testing is a key link, which can help engineers understand and optimize the aerodynamic performance of trains at high speeds. Although traditional wind tunnel testing methods can provide certain data support, they have limitations in detailed measurement and real-time monitoring. For example, traditional wind tunnel tests may rely on limited measurement points and find it difficult to capture the complex dynamics of the entire flow field, which limits the comprehensive understanding of the aerodynamic characteristics of high-speed trains.

[0003] With the development of particle image velocity measurement (PIV), the accuracy and efficiency of wind tunnel tests have been significantly improved. PIV technology scatters tracer particles in the flow field, illuminates the flow field area with a pulsed laser sheet light source, records the image of the particles, and then obtains the flow field velocity distribution through image processing technology. This method can not only achieve transient measurement of the entire flow field, but also is non-contact and will not interfere with the flow field. The application of PIV technology enables wind tunnel tests to provide more detailed and comprehensive flow field data, thereby providing a more accurate reference for the aerodynamic design of high-speed trains.

[0004] However, despite the excellent performance of PIV technology in low-speed wind tunnels, its application in high-speed train (speeds above 200 km / h) wind tunnel tests still faces challenges. For example, how to maintain particle concentration under high wind speeds (above 40 meters per second) and how to evenly spread tracer particles are technical problems that need to be solved. Due to the above problems, the measurement of the flow structure around the high-speed train is inaccurate, which in turn leads to the need to improve the accuracy of the test results. Summary of the invention

[0005] The purpose of the present invention is to provide a high-speed train wind tunnel test system and method based on PIV particle tracing technology to solve the technical problem of uneven dispersion of tracer particles when using PIV technology to obtain flow field velocity distribution in high-speed train wind tunnel tests in the prior art. The specific technical solution is as follows:

[0006] The present invention provides a high-speed train wind tunnel test system based on PIV particle tracing technology, comprising a wind tunnel shell, a tracer particle emitting device, a light curtain assembly, an imaging assembly and a train assembly, wherein the wind tunnel shell is in the shape of an elongated cylinder and is made of a transparent material, the train assembly is movably installed inside the wind tunnel shell, the light curtain assembly is fixed to the outer peripheral bottom of the wind tunnel shell, the imaging assembly is located on the outer peripheral side of the wind tunnel shell, the tracer particle emitting device comprises a storage, a transmission pipeline and a hollow rectifier net, the hollow rectifier net block is fixed at the port of the wind tunnel, the transmission pipeline is connected between the hollow rectifier net and the storage, and a plurality of nozzles are arranged in a matrix on the hollow rectifier net.

[0007] A further improvement of the high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention is that the number of the transmission pipelines is two, and the two transmission pipelines are respectively connected to the two sides of the hollow rectifier network.

[0008] A further improvement of the high-speed train wind tunnel test system based on PIV particle tracing technology of the present invention is that the transmission pipeline includes a main pipe and multiple branch pipes, the multiple branch pipes are evenly spaced and connected between the main pipe and the hollow rectifier network, and the main pipe is connected to the storage.

[0009] A further improvement of the high-speed train wind tunnel test system based on PIV particle tracing technology of the present invention is that the light curtain assembly includes a laser and a reflector fixed to the outer peripheral bottom of the wind tunnel shell, the laser emission port of the laser is opposite to the reflective surface of the reflector, and the reflective surface of the reflector is opposite to the wind tunnel shell.

[0010] A further improvement of the high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention is that the imaging component includes a camera and a bracket, and the camera is installed on the top of the bracket.

[0011] A further improvement of the high-speed train wind tunnel test system based on PIV particle tracing technology of the present invention is that the wind tunnel shell includes an experimental section, a contraction section and a stable section, the cross-sectional area of ​​the experimental section is smaller than the cross-sectional area of ​​the stable section, the contraction section is connected to the experimental section and the stable section, the train assembly is located inside the experimental section, and the hollow rectifier mesh block is fixed at the port of the stable section away from the contraction section.

[0012] A further improvement of the high-speed train wind tunnel test system based on PIV particle tracing technology of the present invention is that the train assembly includes a train model, a model support frame, a lateral angle adjuster and a vertical angle adjuster, the model support frame is adjustably connected to the wind tunnel shell through the vertical angle adjuster, and the train model is adjustably connected to the model support frame through the lateral angle adjuster.

[0013] The present invention also provides a test method for a high-speed train wind tunnel test system based on the PIV particle tracing technology as described above, comprising the following steps:

[0014] Install the high-speed train wind tunnel test system based on PIV particle tracking technology in the wind tunnel laboratory;

[0015] Adjust the running posture of train components and the wind direction of the train;

[0016] Adjust the position of the light curtain assembly to form a laser curtain at the measuring position of the train assembly;

[0017] Adjust the imaging assembly to a position to capture the train assembly and its laser curtain area;

[0018] The storage device is started to move the tracer particles along the transmission pipeline to the hollow rectifier network, and then they are ejected from multiple nozzles and move along the wind tunnel shell toward the train assembly. When the tracer particles move on the laser curtain around the train model, a moving trajectory is formed, and the imaging component captures the movement trajectory of the tracer particles in real time.

[0019] The application of the technical solution of the present invention has the following beneficial effects:

[0020] The high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention can ensure that the tracer particles are evenly spread in the wind tunnel shell by evenly distributing the nozzles on the leeward side of the hollow rectifier net, solving the technical problem of uneven dispersion of tracer particles when the PIV technology is used to obtain the flow field velocity distribution in the high-speed train wind tunnel test in the prior art, thereby ensuring the accuracy and reliability of the test results. The motion trajectory of the tracer particles is captured from multiple angles by the equipped high-speed camera, so that the flow structure around the high-speed train can be accurately captured. This not only provides researchers with a convenient high-speed train wind tunnel test technical solution, but also greatly improves the accuracy and reliability of the test results.

[0021] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 is a perspective view of a high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention;

[0024] Figure 2is a perspective view of a train assembly of a high-speed train wind tunnel test system based on PIV particle tracing technology of the present invention;

[0025] Figure 3 yes Figure 2 Enlarged view of the middle D box;

[0026] Figure 4 yes Figure 2 Enlarged view of frame E in the middle;

[0027] Figure 5 is a perspective view of a tracer particle emitting device of a high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention;

[0028] Figure 6 yes Figure 5 Enlarged view of frame F in the middle;

[0029] Figure 7 is a perspective view of a light curtain assembly of a high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention;

[0030] Figure 8 It is a perspective view of the imaging component of the high-speed train wind tunnel test system based on the PIV particle tracing technology of the present invention.

[0031] Among them, A, experimental section, B, contraction section, C, stable section, 1, train model; 2, model support frame; 3, storage; 4, transmission pipeline; 5, hollow rectifier network; 6, nozzle; 7, laser; 8, reflector; 9, camera; 10, bracket; 11, lateral angle adjuster; 12, block; 13, vertical angle adjuster; 14, pin; 15, concentration sensor; 16, signal transmission line; 17, valve controller. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] See also Figures 1 to 8 As shown, a high-speed train wind tunnel test system based on PIV particle tracing technology includes a wind tunnel shell, a tracer particle emitting device, a light curtain assembly, an imaging assembly and a train assembly. The wind tunnel shell is in the shape of a long cylinder, and the material of the wind tunnel shell is a transparent material. The train assembly is movably installed inside the wind tunnel shell, the light curtain assembly is fixed to the outer bottom of the wind tunnel shell, and the imaging assembly is located on the outer side of the wind tunnel shell. The tracer particle emitting device includes a storage 3, a transmission pipeline 4 and a hollow rectifier network 5. The hollow rectifier network 5 is fixed at the port of the wind tunnel, and the transmission pipeline 4 is connected between the hollow rectifier network 5 and the storage 3. The hollow rectifier network 5 is provided with a plurality of nozzles 6 in a matrix shape.

[0034] Specifically, the cross section of the wind tunnel shell is rectangular, and the hollow rectifying net 5 is a rectangle that matches the wind tunnel shell. The hollow rectifying net 5 is a mesh plate with pipes arranged in a mesh shape, and the nozzle 6 located on the leeward side of the hollow rectifying net is connected to the pipe, so that the tracer particles are evenly sprayed into the wind tunnel.

[0035] Preferably, Figure 5 As shown, there are two transmission pipelines 4, which are respectively connected to the two sides of the hollow rectifier network 5. Furthermore, there are two storages 3, which are arranged in a one-to-one correspondence with the two transmission pipelines 4, so that the tracer particles can be more evenly transported to both sides of the rectifier at the same time.

[0036] Preferably, the transmission pipeline 4 includes a main pipe and a plurality of branch pipes, the plurality of branch pipes are evenly spaced and connected between the main pipe and the hollow rectifying network 5, and the main pipe is connected to the storage 3. Figure 6 As shown, multiple branch pipes are provided with a particle flow control device, which is composed of a particle concentration sensor 15, a signal transmission line 16 and a valve controller 17. The particle concentration sensor can detect the concentration of tracer particles in the branch pipe, and transmit the concentration signal to the valve controller through the signal transmission line. Finally, the valve controller adjusts the valve in real time according to the preset particle concentration value, so that multiple branch pipes can evenly transport tracer particles to each layer of the rectifier pipe. The diameter of the branch pipe should be much smaller than the diameter of the main pipe, so that the number of tracer particles passing through the branch pipe should be much smaller than the number of tracer particles in the main pipe, and ensure that the number of tracer particles passing through each branch pipe is similar.

[0037] Preferably, Figure 7 As shown, the light curtain assembly includes a laser 7 and a reflector 8 fixed to the outer peripheral bottom of the wind tunnel shell, the laser emission port of the laser 7 is relative to the reflective surface of the reflector 8, and the reflective surface of the reflector 8 is relative to the wind tunnel shell. Specifically, the laser emission port is perpendicular to the reflective surface of the reflector 8, the laser 7 can generate fan-shaped laser, and the reflector 8 can refract the fan-shaped laser into a laser curtain.

[0038] Preferably, Figure 8 As shown, the imaging assembly includes a camera 9 and a bracket 10, and the camera 9 is installed on the top of the bracket 10. The camera 9 can be a high-speed camera 9, which records dynamic images at a speed of 1000 to 10000 frames per second, thereby capturing the motion trajectory of the tracer particles from multiple angles.

[0039] Preferably, the wind tunnel shell includes an experimental section A, a contraction section B and a stable section C. The cross-sectional area of ​​the experimental section A is smaller than the cross-sectional area of ​​the stable section C. The contraction section B is connected to the experimental section A and the stable section C. The train assembly is located inside the experimental section A. The hollow rectifier net 5 is fixed to the port of the stable section C away from the contraction section B. The contraction section B is horn-shaped to achieve the connection between the experimental section A and the stable section C. The train assembly is located in the middle of the experimental section A. Among them, the stable section C makes the upstream uneven airflow form many uniform small airflows after passing through the hollow rectifier net 5, and the channel at the rear end of the stable section C further stabilizes the airflow. Since the hollow rectifier net 5 of the stable section C has a certain blocking effect on the airflow, the kinetic energy of the airflow is lost, thereby reducing the wind speed. The contraction section B is arranged downstream of the stable section C. It accelerates the flow speed of the airflow by contracting the area of ​​the airflow flow channel, thereby ensuring that the train model 1 of the experimental section A is impacted by a uniform, stable and sufficient wind speed airflow.

[0040] Preferably, Figure 2 As shown, the train assembly includes a train model 1, a model support frame 2, a lateral angle adjuster 11 and a vertical angle adjuster 13. The model support frame 2 is adjustably connected to the wind tunnel shell through the vertical angle adjuster 13, and the train model 1 is adjustably connected to the model support frame 2 through the lateral angle adjuster 11. The lateral angle adjuster 11 is a connecting member that can make the train model 1 rotate lateral, and the vertical angle adjuster 12 is a connecting member that can make the model support frame 2 rotate vertically. Specifically, as Figure 4 As shown, a fixing rod is provided at the center of the lateral angle adjuster 11, and the fixing rod passes through the model support frame 2 and is fixed to the train model 1. A stopper 12 is fixed on the model support frame 2, and the stopper 12 can be stuck on the teeth of the lateral angle adjuster 11 to limit the lateral rotation angle. Figure 3 As shown, one side of the vertical angle adjuster 13 is fixed to the model support frame 2, and the other side is rotatably connected to the wall of the wind tunnel shell. A latch 14 is connected to the wall of the wind tunnel shell, and the latch 14 is limited on the teeth of the vertical angle adjuster 13, so that the angle of the vertical angle adjuster 13 is rotated to achieve the vertical angle adjustment and limit of the model support frame 2. Through the adjustment of the lateral angle adjuster 11 and the vertical angle adjuster 13, the train model 1 can be rotated in multiple directions on the model support frame 2 to simulate different running postures of the train or different wind direction angle states of the incoming flow.

[0041] like Figures 1 to 8 As shown, the present invention also provides a test method of a high-speed train wind tunnel test system based on the PIV particle tracing technology as described above, comprising the following steps:

[0042] Install the high-speed train wind tunnel test system based on PIV particle tracking technology in the wind tunnel laboratory;

[0043] According to the required research case, the running posture of the train assembly and the incoming wind direction received by the train are adjusted by adjusting the lateral angle adjuster 11 and the vertical angle adjuster 12;

[0044] Adjust the position of the light curtain assembly to form a laser curtain at the measuring position near the train assembly;

[0045] Adjust the imaging assembly to a position to capture the train assembly and its laser curtain area;

[0046] The storage device 3 is started to move the tracer particles along the transmission pipeline 4 to the hollow rectifier network 5, and then ejected by multiple nozzles 6, and moved along the wind tunnel shell toward the train assembly. When the tracer particles move on the laser curtain around the train model 1, a moving track is formed, and the imaging component captures the moving track of the tracer particles in real time. Furthermore, according to the two consecutive particle images obtained by the image acquisition control system, the velocity components v of the particles on the laser curtain in the x-axis and y-axis directions are calculated. x and v y :

[0047]

[0048] Where x(t) is the position of the particle on the x-axis at time t, y(t) is the position of the particle on the y-axis at time t, Δt is the time between taking two consecutive particle images, x(t+Δt) is the position of the tracer particle on the x-axis after time Δt, and y(t+Δt) is the position of the tracer particle on the y-axis after time Δt.

[0049] When adjusting the imaging assembly to the position for photographing the train assembly and its laser curtain area, ensure that the shooting direction of the high-speed camera 9 is in the normal direction of the laser curtain, and can clearly and completely photograph the high-speed train and the laser curtain area around it. When the tracer particles move toward the train assembly along the wind tunnel shell, the tracer particles evenly move toward the train model 1 along the direction of stable section C→contraction section B→experimental section A.

[0050] The storage 3 transports the tracer particles to the inside of the hollow rectifier net 5 through the transmission pipeline 4, and then the nozzle 6 uniformly injects them into the flow field inside the wind tunnel; the laser emitter projects the fan-shaped laser to the reflector 8, which forms a laser curtain on the surrounding section of the high-speed train model 1 after refraction, so that the tracer particles near the train model 1 can be captured by the imaging component; the imaging component is composed of a camera 9 and a bracket 10, which is arranged on the side of the wind tunnel test section A, and can capture the movement process of the tracer particles on the laser surface. The present invention has a simple principle and is easy to operate. The train posture and incoming wind direction can be adjusted according to different test cases, and the flow behavior of incoming flows with different wind speeds and directions around the train can be accurately captured.

[0051] In this embodiment, the running posture of the high-speed train model 1 is adjusted by adjusting the lateral angle adjuster 11, the incoming wind direction of the high-speed train model 1 is changed by using the vertical angle adjuster 12, and the position of the laser curtain is changed by adjusting the positions of the laser 7 and the reflector 8, so that the experimenter can flexibly deal with various high-speed train flow field visualization wind tunnel experiment cases. Figure 6 As shown, in addition, the tracer particle emission device integrates the rectifier network in the traditional wind tunnel, and the particle nozzles 6 are evenly distributed on the leeward side of the rectifier network. The particle concentration sensor 15, the signal transmission line 16 and the valve controller 17 are combined to make the tracer particles evenly spread in the wind tunnel, overcoming the technical difficulties of how to evenly spread the tracer particles, and ensuring the accuracy and reliability of the test results. The high-speed camera 9 is equipped to capture the movement trajectory of the tracer particles from multiple angles, so as to achieve accurate capture of the flow structure around the high-speed train.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-speed train wind tunnel test system based on PIV particle tracing technology, characterized in that: The invention comprises a wind tunnel shell, a tracer particle emission device, a light curtain assembly, an imaging assembly and a train assembly. The wind tunnel shell is in the shape of a long cylinder. The shell material of the wind tunnel stabilization section is a transparent material. The train assembly is movably installed inside the wind tunnel shell. The light curtain assembly is fixed to the outer peripheral bottom of the wind tunnel shell. The imaging assembly is located on the outer peripheral side of the wind tunnel shell. The tracer particle emission device comprises a storage device (3), a transmission pipeline (4) and a hollow rectifying net (5). The hollow rectifying net (5) is blocked and fixed at the port of the wind tunnel. The transmission pipeline (4) is connected between the hollow rectifying net (5) and the reservoir (3). The hollow rectifying net (5) is provided with a plurality of nozzles (6) in a matrix shape.

2. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 1 is characterized in that: The number of the transmission pipelines (4) is two, and the two transmission pipelines (4) are respectively connected to two sides of the hollow rectifying network (5).

3. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 2 is characterized in that: The transmission pipeline (4) comprises a main pipe and a plurality of branch pipes, wherein the plurality of branch pipes are evenly spaced and connected between the main pipe and the hollow rectifying network (5), and the main pipe is connected to the storage device (3).

4. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 1 is characterized in that: The light curtain assembly comprises a laser (7) and a reflector (8) fixed to the outer peripheral bottom of the wind tunnel shell, the laser emission port of the laser (7) is opposite to the reflective surface of the reflector (8), and the reflective surface of the reflector (8) is opposite to the wind tunnel shell.

5. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 1 is characterized in that: The imaging assembly comprises a camera (9) and a bracket (10), wherein the camera (9) is mounted on the top of the bracket (10).

6. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 1 is characterized in that: The wind tunnel shell comprises an experimental section (A), a contraction section (B) and a stable section (C); the cross-sectional area of ​​the experimental section (A) is smaller than the cross-sectional area of ​​the stable section (C); the contraction section (B) is connected to the experimental section (A) and the stable section (C); the train assembly is located inside the experimental section (A); and the hollow rectifier network (5) is blocked and fixed at a port of the stable section (C) away from the contraction section (B).

7. The high-speed train wind tunnel test system based on PIV particle tracing technology according to claim 1 is characterized in that: The train assembly comprises a train model (1), a model support frame (2), a transverse angle adjuster (11) and a vertical angle adjuster (13); the model support frame (2) is adjustably connected to the wind tunnel shell via the vertical angle adjuster (13); and the train model (1) is adjustably connected to the model support frame (2) via the transverse angle adjuster (11).

8. A test method for a high-speed train wind tunnel test system based on PIV particle tracing technology as claimed in claim 1, characterized in that: The steps include: Install the high-speed train wind tunnel test system based on PIV particle tracking technology in the wind tunnel laboratory; Adjust the running posture of train components and the wind direction of the train; Adjust the position of the light curtain assembly to form a laser curtain at the measuring position of the train assembly; Adjust the imaging assembly to a position to capture the train assembly and its laser curtain area; The storage device (3) is started to move the tracer particles along the transmission pipeline (4) to the hollow rectifier network (5), and then the tracer particles are ejected from the plurality of nozzles (6) and move along the wind tunnel shell toward the train assembly. When the tracer particles move on the laser screen around the train model (1), a moving track is formed, and the imaging assembly captures the moving track of the tracer particles in real time.

Images