A drag reduction light shield applicable to a rotating PIV experimental device

Abstract

The present invention discloses a drag-reducing sunshade suitable for a rotating PIV experimental device, including a sunshade, which is installed on the experimental device, and includes a driving assembly and a sunshade plate; the sunshade includes an arc-shaped main board, the upper end surface of the main board is slidably connected to a first sub-board adapted to the main board, the lower end surface of the main board is slidably connected to a second sub-board adapted to the main board, and a light-through slot is provided on the second sub-board; the ends of the first sub-board and the second sub-board away from the main board are respectively transmission-connected to the driving assembly, and stop assemblies are respectively provided between the first sub-board and the second sub-board and the main board; a guide block is fixedly connected to the side of the main board facing the experimental assembly. In the present invention, when the rotating PIV experimental device is being carried out, the experimental model is subjected to lower wind resistance, the electric power provided when a certain speed is reached is reduced, and a higher upper speed limit can be obtained; it also plays a certain protective role on the experimental assembly, and can effectively solve the reflection problem generated during the experiment.

Description

Technical Field

[0001] The present invention relates to the technical field of rotational PIV photography, and particularly to a drag reduction light-shield suitable for a rotational PIV experimental device. Background Art

[0002] Based on flow field visualization, the PIV technology uses computer image processing technology that has developed rapidly recently to quantitatively measure the flow field visualization, thereby realizing the transient measurement of the flow field. For a long period of time, the measurement requirements for complex transient flow structures and flow field characteristics such as vorticity in the flow field have been increasing day by day, requiring multi-point simultaneous measurement of the entire flow field. These requirements cannot be met by single-point measurement technologies, and traditional flow field visualization technologies cannot provide accurate flow field quantification information. Therefore, with the rapid development of computer technology, image processing technology has been greatly improved, and the technology of dispersing tracer particles into the flow field has become increasingly mature. Therefore, the PIV technology has emerged as the times require.

[0003] The PIV photography technology is the preferred technology for studying the flow field mechanism at present. Its basic principle is to disperse a large number of tracer particles (with a particle size less than 10 microns) in the flow field to follow the flow field movement, expand the laser beam into a sheet of light through a combined lens to illuminate the flow field, use a digital camera to take pictures of the flow field, obtain two consecutive frames of particle images, perform cross-correlation calculation on the particle images in the images to obtain the quantitative velocity distribution in a cross-section of the flow field, and further processing can obtain flow field characteristic parameter distributions such as vorticity, streamlines, and isovelocity lines of the flow field.

[0004] At present, various efficient cooling methods are widely used in the turbine blades of aeroengines, mainly including external cooling and internal cooling technologies. And it is of great significance to use the PIV technology to photograph and construct the flow field of the cooling structure model under a rotating state to understand the internal flow mechanism for optimizing the cooling structure.

[0005] However, limited by the model material and the shooting method, the irradiation of the laser will produce a certain amount of reflection, and the generated light spots prevent the camera from accurately photographing the positions of the tracer particles; when conducting a rotating experiment, it is usually necessary to reach a relatively high rotational speed to approach the actual situation, but due to the differences and limitations in the model shape, a large amount of wind resistance will be generated during the rotation process, so that the motor cannot reach the maximum rotational speed; moreover, the long-term rotation against the wind will generate a certain amount of vibration, which will have an adverse impact on the model structure strength and the shooting stability. This problem has posed a great obstacle to conducting high-speed PIV experiments. Therefore, there is an urgent need for a drag reduction light-shield suitable for a rotational PIV experimental device to solve the influence of wind resistance on the model and the reflection problem in the rotational PIV experimental device. Summary of the Invention

[0006] The object of the present invention is to provide a drag-reducing light-shielding cover applicable to a rotating PIV experimental device to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following solution: The present invention provides a drag-reducing light-shielding cover applicable to a rotating PIV experimental device, including a light-shielding cover, the light-shielding cover is installed on an experimental component, and the light-shielding cover includes a driving component and a light-shielding plate; the driving component is in transmission connection with the light-shielding plate;

[0008] The light-shielding plate includes a main board arranged in an arc shape, a first sub-board adapted to the main board is slidably connected to the upper end surface of the main board, a second sub-board adapted to the main board is slidably connected to the lower end surface of the main board, and a light-passing groove is formed through the second sub-board;

[0009] One ends of the first sub-board and the second sub-board away from the main board are respectively in transmission connection with the driving component, and a stopping component is arranged between the first sub-board and the second sub-board and the main board respectively;

[0010] A flow guiding block is fixedly connected to one side of the main board facing the experimental component.

[0011] Preferably, one side of the flow guiding block away from the experimental component is symmetrically arranged in an arc shape, and the arc shape protrudes towards the experimental component; the other side of the flow guiding block is attached to and fixedly connected to the arc-shaped surface of the inner wall of the main board.

[0012] Preferably, the stopping component is a stopping rack fixedly connected in the main board, the stopping rack is detachably connected with a positioning tooth, the positioning tooth is slidably connected with a stopping hole formed in the first sub-board, an electromagnet is installed at the bottom end of the stopping hole, a permanent magnet is fixedly connected to one end of the positioning tooth facing the electromagnet, and the permanent magnet and the electromagnet are arranged in a mutually repulsive manner; a stopping spring is fixedly connected between the permanent magnet and the electromagnet.

[0013] Preferably, the driving component includes two driving motors fixedly installed on the experimental component, the two driving motors are in contact with each other; the output ends of the two driving motors are in opposite directions; the fixed ends of telescopic rods are respectively in transmission connection with the two driving motors, and the movable ends of the telescopic rods are respectively in transmission connection with the first sub-board and the second sub-board.

[0014] Preferably, the telescopic rod includes a sleeve fixedly connected to the output shaft of the driving motor. An active rod is slidably connected inside the sleeve. One end of the active rod away from the sleeve is perpendicularly fixedly connected with a connecting rod facing the main board. One connecting rod is inserted into one end of the first auxiliary board away from the main board and rotatably connected to the first auxiliary board. The other connecting rod is inserted into one end of the second auxiliary board away from the main board and rotatably connected to the second auxiliary board. A power member is drivingly connected between the active rod and the sleeve.

[0015] Preferably, the power member includes an adjustment motor fixedly installed at the bottom end of the inner cavity of the sleeve. The output shaft of the adjustment motor is drivingly connected with an adjustment screw rod. The adjustment screw rod extends into the bottom end of the active rod and is threadedly connected with the active rod.

[0016] Preferably, the output shaft of the adjustment motor and the adjustment screw rod are drivingly connected through a brake; a self-locking nut is threadedly connected to the adjustment screw rod.

[0017] Preferably, the main board, the first auxiliary board and the second auxiliary board are made of high-toughness and high-temperature-resistant materials; the sides of the main board, the first auxiliary board and the second auxiliary board facing the experimental component are sprayed with matte black color.

[0018] The present invention discloses the following technical effects: The present invention discloses a drag reduction and light-shielding cover applicable to a rotating PIV experimental device, which is mainly used to solve the problem that when the experimental component in the existing rotating PIV experimental device rotates at a high speed, the camera cannot accurately capture the position of the tracer particles due to the influence of light reflection, and at the same time solve the problems that the rotation speed cannot reach the predetermined value due to wind resistance during high-speed rotation and the vibration of the experimental component caused by wind resistance; the present invention installs corresponding light-shielding plates on the experimental component. The light-shielding plates are drivingly connected with the driving component to drive the light-shielding plates to shade the experimental component in all directions, preventing the problem that the camera cannot capture the tracer particles caused by light reflection; at the same time, the light-shielding plates are arc-shaped and arranged around the experimental component, reducing the wind resistance of the rotation of the experimental component, preventing the problem that the experimental component cannot reach the predetermined rotation speed due to wind resistance, and at the same time reducing the vibration of the experimental component caused by wind resistance, making the experimental results more accurate; the light-shielding plate includes a main board connected in a sliding manner and a first auxiliary board and a second auxiliary board slidably connected to both ends of the main board. The driving component drives the first auxiliary board and the second auxiliary board to slide in the main board, adjusting the distance between the light-shielding plate and the experimental component and the light-shielding range of the light-shielding plate, which is applicable to experimental components of different specifications, preventing inflexible use and increased wind resistance caused by being too large, and also preventing insufficient shielding of the experimental component caused by the light-shielding plate being too small, with a wide range of applications. The present invention enables the experimental model to be subjected to lower wind resistance during the operation of the rotating PIV experimental device, reduces the electric power provided when reaching a certain rotation speed, and can obtain a higher rotation speed limit; it also plays a certain protective role for the experimental component and can effectively solve the problem of light reflection generated during the experiment. Brief Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is an axonometric view of the drag reduction light-shielding cover applicable to the rotary PIV experimental device of the present invention;

[0021] Figure 2 It is a side view of the drag reduction light-shielding cover applicable to the rotary PIV experimental device of the present invention;

[0022] Figure 3 It is a front view of the drag reduction light-shielding cover applicable to the rotary PIV experimental device of the present invention;

[0023] Figure 4 It is a schematic installation view of the drag reduction light-shielding cover applicable to the rotary PIV experimental device of the present invention;

[0024] Figure 5 It is a side view of the drag reduction light-shielding cover applicable to the rotary PIV experimental device of the present invention;

[0025] Figure 6 It is a schematic structural view of the telescopic rod of the present invention;

[0026] Figure 7 It is a schematic structural view of the stop component of the present invention;

[0027] Figure 8 It is a schematic view of the light-shielding cover adjustment form of the present invention;

[0028] Figure 9 It is a graph of the change in the drag coefficient related to the rotational speed of the present invention;

[0029] Among them, 1. Light-shielding plate; 2. Driving component; 3. Experimental component; 11. Main board; 12. First sub-board; 13. Second sub-board; 14. Light-passing slot; 15. Flow guiding block; 16. Stop rack; 17. Positioning tooth; 18. Stop hole; 19. Electromagnet; 110. Permanent magnet; 111. Stop spring; 21. Driving motor; 22. Telescopic rod; 23. Sleeve; 24. Movable rod; 25. Connecting rod; 26. Adjusting motor; 27. Adjusting screw; 28. Brake; 29. Self-locking nut; 31. Control computer; 32. Digital-to-analog conversion device; 33. Signal slip ring; 34. Rotating shaft; 35. Rotating arm; 36. Experimental model; 37. Laser generating device; 38. Camera. Detailed Embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Referring to Figures 1-9 , the present invention provides a drag-reducing light-shielding cover applicable to a rotary PIV experimental device, including a light-shielding cover, which is installed on an experimental component 3. The light-shielding cover includes a driving component 2 and a light-shielding plate 1; the driving component 2 is in transmission connection with the light-shielding plate 1;

[0033] The light-shielding plate 1 includes a main board 11 arranged in an arc shape. A first sub-board 12 adapted to the main board 11 is slidably connected to the upper end surface of the main board 11. A second sub-board 13 adapted to the main board 11 is slidably connected to the lower end surface of the main board 11. A light-passing groove 14 is formed through the second sub-board 13.

[0034] One ends of the first sub-board 12 and the second sub-board 13 away from the main board 11 are respectively in transmission connection with the driving component 2. A stopping component is arranged between the first sub-board 12 and the second sub-board 13 and the main board 11 respectively.

[0035] A flow guiding block 15 is fixedly connected to the side of the main board 11 facing the experimental component 3.

[0036] The present invention discloses a drag-reducing shading cover suitable for a rotating PIV experimental device, which is mainly used to solve the problem that the camera 38 cannot accurately capture the position of tracer particles due to the influence of light reflection when the experimental component 3 in the existing rotating PIV experimental device rotates at high speed, and solves the problem that the rotation speed of the experimental component 3 cannot reach a predetermined value due to wind resistance during high-speed rotation and the vibration of the experimental component 3 caused by wind resistance; the present invention installs a corresponding shading plate 1 on the experimental component 3, and the shading plate 1 is connected to the driving component 2 in a transmission manner, so as to drive the shading plate 1 to shield the experimental component 3 in all directions, so as to prevent the problem that the camera 38 cannot capture the tracer particles due to light reflection; at the same time, the shading plate 1 is arranged in an arc shape at The periphery of the experimental component 3 reduces the wind resistance of the experimental component 3 during rotation, prevents the problem that the experimental component 3 cannot reach the predetermined rotation speed due to wind resistance, and at the same time reduces the vibration of the experimental component 3 caused by wind resistance, making the experimental result more accurate; the shading plate 1 includes a slidingly connected main board 11 and a first sub-board 12 and a second sub-board 13 slidingly connected at both ends of the main board 11, and the driving component 2 drives the first sub-board 12 and the second sub-board 13 to slide in the main board 11, adjusts the distance from the shading plate 1 to the experimental component 3 and the shading range of the shading plate 1, and is suitable for use with experimental components 3 of different specifications, prevents inflexible use and increased wind resistance due to being too large, and prevents insufficient shielding of the experimental component 3 due to being too small, and has a wide range of applications.

[0037] Furthermore, the experimental component 3 includes a control computer 31, a digital-to-analog conversion device 32, a signal slip ring 33, a rotating shaft 34, a rotating arm 35, an experimental model 36, a laser generating device 37, and a camera 38; wherein the rotating shaft 34 is connected to the rotating arm 35, the shading plate 1, the experimental model 36 and the driving component 2 are all fixed on the rotating arm 35, the signal slip ring 33 is installed at the upper end of the rotating shaft 34, and its output end is connected to the driving component 2 through a signal line, and its input end is connected to the digital-to-analog conversion device 32 through a signal line and then connected to the control computer 31; the sheet laser emitted by the laser generating device 37 is irradiated onto the experimental model 36 through the light-passing groove 14, and the camera 38 shoots the area irradiated by the sheet laser from top to bottom, and transmits the captured image to the control computer 31.

[0038] Further optimization scheme, the side of the guide block 15 away from the experimental component 3 is symmetrically arranged in an arc shape, and the arc shape protrudes toward the experimental component 3; the other side of the guide block 15 is attached to and fixed to the arc surface of the inner wall of the main board 11. The purpose of the guide block 15 is to reduce the wind resistance of the inner wall of the main board 11; at the same time, according to the Bernoulli fluid principle, when the airflow flows through, the flow velocity of the airflow on the outside is slow and the flow velocity on the inside is fast. The setting of the guide block 15 can make the pressure on the outside greater than the pressure on the inside when the airflow flows through, providing inward pressure for the main board 11, so that the sunshade 1 has an inward pressing force when facing the wind and will not be blown up, which improves the stability of the sunshade 1 itself when rotating at high speed.

[0039] A further optimized solution is that the stop assembly is fixedly connected to the stop rack 16 in the main board 11, and the stop rack 16 is detachably connected with a positioning tooth 17, and the positioning tooth 17 is slidably connected to a stop hole 18 opened on the first sub-plate 12, and an electromagnet 19 is installed at the bottom end of the stop hole 18, and a permanent magnet 110 is fixedly connected to one end of the positioning tooth 17 facing the electromagnet 19, and the permanent magnet 110 and the electromagnet 19 are mutually exclusive; a stop spring 111 is fixedly connected between the permanent magnet 110 and the electromagnet 19. The function of the stop assembly is to improve the stability between the main board 11 and the sub-board. Under the control of the digital-to-analog converter, after the telescopic rod 22 adjusts the position of the main board 11 and the sub-board, the electromagnet 19 is energized to make the electromagnet 19 and the permanent magnet 110 repel each other, and the positioning tooth 17 is pushed toward the stop rack 16 and stuck therewith, to prevent the main board 11 and the sub-board from moving or even damaging the sunshade 1 due to vibration and wind resistance during high-speed rotation; when positioning is not required, the electromagnet 19 is powered off and loses the mutual repulsion with the permanent magnet 110, and the stop spring 111 drives the positioning tooth 17 to reset, and it no longer has a positioning function.

[0040] Further optimization scheme, the driving assembly 2 includes two driving motors 21 fixedly mounted on the experimental assembly 3, the two driving motors 21 are mutually abutted; the output ends of the two driving motors 21 are in opposite directions; the two driving motors 21 are respectively connected to the fixed ends of the telescopic rod 22, and the movable ends of the telescopic rod 22 are respectively connected to the first sub-plate 12 and the second sub-plate 13. The two driving motors 21 are independently controlled by the digital-to-analog conversion device 32, and the size of the sunshade 1 can be adjusted through independent movements. The principle is that the rotation angles of the two telescopic rods 22 are different, and the first sub-plate 12 and the second sub-plate 13 are pulled out or inserted from the main board 11, and the telescopic rods 22 are extended or shortened in coordination to adjust the size of the sunshade 1; when the two driving motors 21 are output synchronously and the telescopic rods 22 do not change, the sunshade 1 can be driven by the two telescopic rods 22 to rotate with the two driving motors 21 as the axis, so that the sunshade 1 faces the windward side.

[0041] A further optimized solution is as follows: the telescopic rod 22 includes a sleeve 23 fixedly connected to the output shaft of the driving motor 21, a movable rod 24 is slidably connected in the sleeve 23, and the end of the movable rod 24 away from the sleeve 23 is vertically fixed with a connecting rod 25 facing the main board 11, one connecting rod 25 is inserted into the end of the first sub-plate 12 away from the main board 11 and is rotatably connected to the first sub-plate 12, and the other connecting rod 25 is inserted into the end of the second sub-plate 13 away from the main board 11 and is rotatably connected to the second sub-plate 13; a power part is transmission-connected between the movable rod 24 and the sleeve 23; the power part includes an adjusting motor 26 fixedly mounted at the bottom end of the inner cavity of the sleeve 23, and the output shaft of the adjusting motor 26 is transmission-connected with an adjusting screw 27, which extends into the bottom end of the movable rod 24 and is threadedly connected to the movable rod 24. The output shaft of the driving motor 21 drives the sleeve 23 to rotate with the output shaft of the driving motor 21, thereby adjusting the angle of the sleeve 23; the adjusting motor 26 drives the adjusting screw 27 to rotate, so that the length of the adjusting screw 27 screwed into the movable rod 24 increases or decreases, and then the movable rod 24 moves closer to or away from the adjusting motor 26 and slides in the sleeve 23, adjusting the length of the extended sleeve 23 to achieve the purpose of telescopic extension; compared with conventional hydraulic rods, the telescopic rod 22 of the present application is faster to adjust, smaller in size, and does not need to be equipped with bulky hydraulic equipment, and is more convenient to use.

[0042] Further optimization scheme, the output shaft of the adjusting motor 26 is connected to the adjusting screw 27 through the brake 28; the adjusting screw 27 is threaded with a self-locking nut 29. The brake 28 is arranged between the output shaft of the adjusting motor 26 and the adjusting screw 27, and is electrically connected to the signal slip ring 33, and is controlled to connect or disconnect the connection between the adjusting motor 26 and the adjusting screw 27; the self-locking nut 29 is fixed to the bottom end of the movable rod 24, and the self-locking nut 29 has a 30° wedge-shaped inclined surface at the bottom of the internal thread of the self-locking nut 29. When the adjusting screw 27 and the self-locking nut 29 are tightened with each other, the external thread of the adjusting screw 27 is tightly pressed against the wedge-shaped inclined surface of the internal thread of the self-locking nut 29, generating a large locking force, realizing the self-locking function, and the length of the telescopic rod 22 will not change due to the vibration generated during rotation.

[0043] Further optimization scheme, the main board 11, the first sub-board 12 and the second sub-board 13 are made of high toughness and high temperature resistant materials; the main board 11, the first sub-board 12 and the second sub-board 13 are sprayed with matte black color on the side facing the experimental component 3. The materials of the main board 11, the first sub-board 12 and the second sub-board 13 need to have high toughness and high temperature resistance, including but not limited to copolycarbonate (PC-HT); the purpose of matte black color is to increase the light shielding property of the sunshade 1 and improve the light shielding ability.

[0044] Directions:

[0045] According to the attached Figure 1Assemble the test device in the form of [description], and initially select the appropriate size of the light-shielding plate 1 according to the specifications of the experimental model 36. The adjustment method is to control the asynchronous output of the output ends of the two driving motors 21, so as to change the angles of the two telescopic rods 22. At the same time, control the extension length of the movable rod 24 of the telescopic rod 22. The combined control enables the adjustment of the specifications of the light-shielding plate 1 and the distance from the experimental model 36. After the adjustment is in place, lock the positions of the main board 11 and the sub-board through the stop assembly to improve stability. At the same time, lock the self-locking screw through the self-locking nut 29 threadedly connected to the adjustment screw 27 to prevent the telescopic rod 22 from changing.

[0046] During the rotation experiment, the light-shielding plate 1 always faces the windward side. Therefore, every time the control computer 31 sends a rotation signal, the digital-to-analog conversion device 32 will convert its digital signal into an analog signal, and then send the control instruction to the signal slip ring 33. The signal slip ring 33 then transmits the signal to the two driving motors 21, and then the two driving motors 21 rotate the light-shielding plate 1 to face the windward side according to the instruction.

[0047] When it is necessary to replace the smaller experimental model 36 for shooting, first make the control computer 31 issue an instruction to synchronously shorten the two telescopic rods 22 to a suitable position; at the same time, control the adjustment motor 26 in the upper telescopic rod 22 to rotate clockwise. At the same time, the upper sleeve 23 will drive the movable rod 24 to move, and then the first sub-board 12 of the light-shielding plate 1 will be inserted into the groove of the main board 11 and continue to move until it reaches a suitable position, and then lock it through the stop assembly; if the space above the light-shielding plate 1 is not large enough to block the shooting field of view of the camera 38, the telescopic rod 22 can be operated to completely insert the first sub-board 12 into the groove of the main board 11; when it is necessary to replace the larger experimental model 36, first make the control computer 31 issue an instruction to extend the two telescopic rods 22 to an appropriate position. At this time, the upper sleeve 23 will drive the movable rod 24 to move, and then the second sub-board 13 of the light-shielding plate 1 will move to increase the area of the light-shielding plate 1.

[0048] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying 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 construed as a limitation of the present invention.

[0049] The above embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A drag-reducing light-shielding cover applicable to a rotary PIV experimental device, comprising a light-shielding cover, wherein the light-shielding cover is mounted on an experimental component (3), and is characterized in that: The light shield includes a driving component (2) and a light-shielding plate (1); the driving component (2) is in transmission connection with the light-shielding plate (1); The light-shielding plate (1) includes a main board (11) arranged in an arc shape. A first sub-board (12) adapted to the main board (11) is slidably connected to the upper end surface of the main board (11). A second sub-board (13) adapted to the main board (11) is slidably connected to the lower end surface of the main board (11). A light-passing groove (14) is formed through the second sub-board (13); One ends of the first sub-board (12) and the second sub-board (13) far from the main board (11) are respectively in transmission connection with the driving component (2). A stop component is arranged between the first sub-board (12) and the second sub-board (13) and the main board (11); A diversion block (15) is fixedly connected to one side of the main board (11) facing the experimental component (3); The driving component (2) includes two driving motors (21) fixedly installed on the experimental component (3). The two driving motors (21) are in contact with each other; the output ends of the two driving motors (21) are in opposite directions; the output ends of the two driving motors (21) are respectively in transmission connection with the fixed ends of telescopic rods (22). The movable ends of the telescopic rods (22) are respectively in transmission connection with the first sub-board (12) and the second sub-board (13).

2. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 1, wherein: The diversion block (15) is symmetrically arranged in a circular arc shape, and the circular arc protrudes towards the experimental component (3); one side of the diversion block (15) far from the experimental component (3) is attached to and fixedly connected to the arc surface of the inner wall of the main board (11).

3. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 1, wherein: The stop component includes a stop rack (16) fixedly connected inside the main board (11). The stop rack (16) is detachably connected with a positioning tooth (17). The positioning tooth (17) is slidably connected to a stop hole (18) formed in the first sub-board (12). An electromagnet (19) is installed at the bottom end of the stop hole (18). A permanent magnet (110) is fixedly connected to one end of the positioning tooth (17) facing the electromagnet (19). The permanent magnet (110) and the electromagnet (19) are arranged in a mutually repulsive manner; a stop spring (111) is fixedly connected between the permanent magnet (110) and the electromagnet (19).

4. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 1, characterized in that: The telescopic rod (22) includes a sleeve (23) fixedly connected to the output shaft of the driving motor (21). A movable rod (24) is slidably connected inside the sleeve (23). One end of the movable rod (24) far from the sleeve (23) is vertically fixedly connected with a connecting rod (25) facing the main board (11). One connecting rod (25) is inserted into one end of the first sub-board (12) far from the main board (11) and is rotatably connected to the first sub-board (12). The other connecting rod (25) is inserted into one end of the second sub-board (13) far from the main board (11) and is rotatably connected to the second sub-board (13); a power component is in transmission connection between the movable rod (24) and the sleeve (23).

5. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 4, characterized in that: The power component includes an adjustment motor (26) fixedly installed at the bottom end of the inner cavity of the sleeve (23). The output shaft of the adjustment motor (26) is drivingly connected to an adjustment screw rod (27). The adjustment screw rod (27) extends into the bottom end of the movable rod (24) and is threadedly connected to the movable rod (24).

6. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 5, wherein: The output shaft of the adjustment motor (26) is drivingly connected to the adjustment screw rod (27) through a brake (28); a self-locking nut (29) is threadedly connected to the adjustment screw rod (27).

7. The drag reduction light-shielding cover applicable to the rotary PIV experimental device according to claim 1, wherein: The main board (11), the first sub-board (12) and the second sub-board (13) are made of high-toughness and high-temperature-resistant materials; the sides of the main board (11), the first sub-board (12) and the second sub-board (13) facing the experimental component (3) are sprayed with matte black color.

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