A wind tunnel test attack angle adjusting device and an attached layer thickness measuring and calculating method thereof

Abstract

This invention provides a wind tunnel test angle-of-attack adjustment device and its calculation method. The device includes an angle-of-attack mechanism, a suction mechanism, a front wind speed sensing component, and a rear wind speed sensing component. The suction mechanism includes a suction channel and a fan. Both the front and rear wind speed sensing components include a high-sensitivity sensor and a lifting drive component. The front wind speed sensing component also includes a low-sensitivity sensor, located downstream of the suction channel. The high-sensitivity and low-sensitivity sensors are connected to the fan and the lifting drive component via a control unit. The method includes selecting a working sensor based on the test angle of attack adjusted by the angle-of-attack mechanism; setting the target boundary layer thickness and the wind tunnel set flow rate; adjusting the real-time power of the fan; controlling the height of the working high-sensitivity sensor; and obtaining the flow rates of the high-sensitivity and low-sensitivity sensors; adjusting the real-time power of the fan based on the flow rates of the high-sensitivity and low-sensitivity sensors. This invention has advantages such as effectively controlling the boundary layer thickness and improving test accuracy.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing, and in particular to a wind tunnel testing angle-of-attack adjustment device and a method for calculating the boundary layer thickness. Background Technology

[0002] Wind tunnel testing refers to a testing method in which a physical model of the research object (such as a tall building, bridge, wind turbine tower, etc.) is installed in a wind tunnel to study gas flow and its interaction with the model in order to understand the aerodynamic characteristics of the actual research object. A wind tunnel is a pipe-shaped test device that can artificially generate and control airflow to simulate the flow of gas around an aircraft or object, and can measure the effect of gas on the object and observe physical phenomena.

[0003] In wind tunnel tests, the diameter of the wind tunnel test section is limited, and the physical model often needs to be scaled down compared to the actual object. During the test, the test model may be situated within the boundary layer (air near the wall is stagnant, forming a boundary layer), thus affecting the accuracy of the test data. Specifically, for example... Figure 1 As shown, Figure 1 This diagram illustrates the air velocity distribution near the walls of a wind tunnel, where v is the air velocity, v0 is the wind tunnel's set velocity, and h is the distance of the air from the wall. As h approaches 0, v approaches 0; as h gradually increases, v gradually increases to v0. When the air velocity v output by the wind tunnel is equal to the wind tunnel's set velocity v0, the corresponding h0 is the boundary layer thickness.

[0004] Existing wind tunnels typically consist of multiple sections. The wind tunnel test section is where test models are installed. With the development of aerodynamic technology, the wind tunnel test section is often equipped with angle-of-attack mechanisms that can adjust the angle of attack of the test models, thereby guiding airflow to conduct wind tunnel tests on the models under different angles of attack. In wind tunnel testing, the ideal state for the test model is in air with a uniform velocity distribution. However, in actual testing, the angle-of-attack structures in existing wind tunnels cannot achieve boundary layer disruption, resulting in some test models being located within the boundary layer. This leads to localized low airflow velocities and affects the accuracy of the test results. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a wind tunnel test angle of attack adjustment device and its calculation method that can effectively control the boundary layer thickness and improve the test accuracy.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A wind tunnel test angle of attack adjustment device includes an angle of attack mechanism disposed in the wind tunnel test section. The angle of attack mechanism includes a front plate, a middle plate and a rear plate that are sequentially and movably connected along the airflow direction. It also includes a suction mechanism with the inlet located upstream of the front plate, a front wind speed sensing component disposed at the end of the front plate and a rear wind speed sensing component disposed at the front end of the rear plate. The suction mechanism includes a suction channel and a fan disposed in the suction channel.

[0008] Both the front and rear wind speed sensing components include high-sensitivity sensors that detect the flow velocity at different heights from the wall surface of the front or rear panel, and a lifting drive component that adjusts the distance between the high-sensitivity sensor and the wall surface. The front wind speed sensing component also includes a low-sensitivity sensor that detects the airflow direction near the wall surface of the front panel. The low-sensitivity sensor is located downstream of the suction channel. The high-sensitivity sensor and the low-sensitivity sensor are connected to the fan and the lifting drive component through a control unit.

[0009] As a further improvement to the above technical solution:

[0010] It also includes a boundary layer wind-breaking assembly that weakens the boundary layer at a positive angle of attack. The boundary layer wind-breaking assembly includes a guide fixing plate, an elastic sheet, and an elastic rope. One end of the guide fixing plate is fixed to the upper surface of the front plate, and the other end extends above the middle plate. The guide fixing plate has multiple wind-breaking slots that are arranged through the airflow direction. The elastic sheet consists of multiple elastic sheets corresponding to the upper surface of the wind-breaking slots to form a wind-breaking zone that prevents vortices from forming at the front end of the middle plate. One end of the elastic sheet is fixedly connected to the guide fixing plate, and the other end is fixed to the upper surface of the middle plate by the elastic rope.

[0011] It also includes a boundary layer wind deflector assembly that weakens the boundary layer at a positive angle of attack. The boundary layer wind deflector assembly includes a drive cable, a rotating wheel assembly mounted on the front plate, a fixed pulley assembly mounted on the middle plate, and deflector blades arranged in the direction of airflow. The rotating wheel assembly and the fixed pulley assembly are located in the same plane along the direction of airflow. One end of the drive cable is fixed to the middle plate, and the other end is sequentially wound around the fixed pulley assembly and the rotating wheel assembly. A plurality of deflector blades are arranged perpendicular to the direction of airflow and are mounted on the rotating wheel assembly. The deflector blades rotate downward at a positive angle of attack to form a wind deflector zone that forces the airflow to flow toward the wall of the middle plate and disrupts the vortex.

[0012] The deflector blades are at least two layers, and the multiple layers of deflector blades are arranged along the height direction. The number of rotating wheel assemblies is the same as the number of deflector blades and they are arranged in a one-to-one correspondence. Adjacent rotating wheel assemblies are synchronized by a transmission belt or gear set, and one group of rotating wheel assemblies is driven to the fixed pulley assembly by the transmission cable.

[0013] The suction mechanism consists of multiple sets, which are arranged perpendicular to the airflow direction. The inlets of the suction channels of each suction mechanism are connected through the same connecting channel. The connecting channel is provided with suction orifice plates arranged along the length of the connecting channel. The outlet end of the suction channel is located at the return air inlet connected to the wind tunnel test section.

[0014] The suction mechanism also includes a pressure stabilizing chamber for stabilizing and homogenizing the airflow, a honeycomb structure for forcing the airflow to be straightened, and a damping mesh for weakening large-scale eddy turbulence on the suction side. The honeycomb structure, damping mesh, and fan are arranged sequentially along the suction direction of the suction channel through a duct. The pressure stabilizing chamber is connected between the suction orifice plate and the duct, and the vertical flow dimension of the pressure stabilizing chamber is larger than the diameter of the duct.

[0015] The angle-of-attack mechanism also includes a lifting component that drives the plate to change its angle. The lifting component includes a mounting base, a power source, and a drive rod. The lower end of the power source is mounted on the mounting base via a lower hinge component, and the upper end of the power source is connected to an upper hinge component via the drive rod. The upper hinge component is hinged to the end of the front plate, the middle plate, or the rear plate, respectively.

[0016] A method for calculating boundary layer thickness based on the wind tunnel test angle-of-attack adjustment device described above, the method comprising the following steps:

[0017] Step 1), select the working sensor according to the test angle of attack adjusted by the angle of attack mechanism: when the angle of attack mechanism is at a negative angle of attack, the high-sensitivity sensor in the front wind speed sensing component is activated; when the angle of attack is positive, the high-sensitivity sensor in the rear wind speed sensing component is activated; the low-sensitivity sensor is always working.

[0018] Step 2), set the target boundary layer thickness H0 and the wind tunnel set velocity V0, adjust the real-time power P of the fan to 20~50% of the rated power P0 of the fan, and control the lifting drive to adjust the height H of the working high-sensitivity sensor to the target boundary layer thickness H0, and obtain the velocity V1 detected by the high-sensitivity sensor and the velocity V2 detected by the low-sensitivity sensor.

[0019] Step 3) Adjust the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor and / or the flow velocity V1 detected by the high-sensitivity sensor, so as to control the boundary layer thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan when the boundary layer thickness cannot be controlled to be at or below H0. As a further improvement of the above technical solution: In step 3), adjusting the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor and / or the flow velocity V1 detected by the high-sensitivity sensor includes: when V2 < 0, reducing the real-time power P of the fan until V2 = 0, and maintaining the real-time power P of the fan in this state; then, raising the height H of the corresponding high-sensitivity sensor by the lifting drive until V1 = V0, at which time the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the wind tunnel set flow velocity V0;

[0020] When V2 > 0, compare the relationship between the flow velocity V1 detected by the high-sensitivity sensor and the wind tunnel set flow velocity V0. Based on the relationship between V1 and V0, determine whether to adjust the real-time power P of the fan to control the boundary layer thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan.

[0021] The step of determining whether to adjust the real-time power P of the fan based on the relationship between V1 and V0 includes:

[0022] When V1=V0, without adjusting the real-time power P of the fan, the height H of the high-sensitivity sensor is at or below H0.

[0023] When V1 < V0, the real-time power P of the fan is increased. During the process of increasing the real-time power P of the fan, if P < P0 and V2 > 0, the real-time power P of the fan is continuously increased until V1 = V0. At this time, it is determined that the boundary layer thickness H is controlled to the target boundary layer thickness H0. If P = P0 and V2 > 0, the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the rated power P0 of the fan. If P = P0 and V2 = 0, the increase of the real-time power P of the fan is stopped. At this time, the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the set flow velocity V0 of the wind tunnel.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] (1) The present invention is based on the angle of attack mechanism and has a suction mechanism. The suction mechanism includes a suction channel and a fan. The inlet of the suction channel is located upstream of the front plate, and the fan is located inside the suction channel. At this time, the fan can adsorb the wall airflow at the front end of the front plate into the suction channel, so as to effectively destroy the vortex generated at the front end of the front plate, destroy the boundary layer, reduce the thickness of the boundary layer, and make the wind speed simulation more closely resemble the actual situation. This effectively improves the accuracy of the wind tunnel test results and can adapt to different test conditions and test models of different sizes, thus providing a basis for aerodynamic research.

[0026] (2) The present invention sets a front wind speed sensing component at the end of the front plate and a rear wind speed sensing component at the front end of the rear plate. By setting different sensing components on the front plate and the rear plate respectively, the wind speed and wind direction data of the angle of attack mechanism at different test angles of attack can be effectively and quickly measured, ensuring the accurate detection and control of the subsequent boundary layer thickness. Moreover, its structure is compact and occupies little space, realizing a high degree of integration of boundary layer control and measurement functions.

[0027] Both the front and rear wind speed sensing components are equipped with high-sensitivity sensors and lifting actuators. The high-sensitivity sensors detect the flow velocity at different heights from the wall surface of the front or rear plate, providing reliable and accurate experimental data for adjusting the boundary layer thickness at different angles of attack. The lifting actuators adjust the distance of the high-sensitivity sensors from the wall surface, facilitating adjustment of the sensor height to the desired boundary layer thickness. The front wind speed sensing component also includes a low-sensitivity sensor located downstream of the suction channel. This sensor detects the airflow direction near the wall surface of the front plate when the fan is operating, preventing excessive fan power from causing the airflow direction to be opposite to the wall surface, thus ensuring the validity and accuracy of the test results. The high-sensitivity and low-sensitivity sensors are connected to the fan and lifting actuators via a control unit, enabling effective automatic adjustment and control of the boundary layer thickness through boundary layer height measurement.

[0028] The boundary layer thickness measurement method of the present invention also has the above-mentioned advantages. The method of the present invention obtains accurate and reliable measurement data through multi-parameter monitoring using high-sensitivity and low-sensitivity sensors. The real-time power of the fan is adjusted according to the airflow direction detected by the low-sensitivity sensor and / or the flow velocity detected by the high-sensitivity sensor, thereby controlling the boundary layer thickness to be at or below the target boundary layer thickness, or obtaining the thinnest boundary layer thickness under the wind tunnel set flow velocity or the rated power of the fan when the boundary layer thickness cannot be controlled to be at or below the target thickness. In other words, the boundary layer thickness can be quickly and accurately adjusted according to different test conditions, effectively solving the problem of difficult boundary layer control in the prior art, further improving test efficiency and accuracy, providing accurate reference data for the test, and is easy to operate. Attached Figure Description

[0029] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the air velocity distribution near each wall in the wind tunnel of this invention;

[0031] Figure 2 This is a schematic diagram of the wind tunnel test angle of attack adjustment device of the present invention in a specific application;

[0032] Figure 3 This is a top view of the wind tunnel test angle of attack adjustment device of the present invention;

[0033] Figure 4 yes Figure 3 A sectional view of section AA (the angle of attack mechanism is 0°).

[0034] Figure 5 yes Figure 3 A sectional view of section AA (the angle of attack mechanism is a negative angle of attack).

[0035] Figure 6 yes Figure 3 A sectional view of section AA (the angle of attack mechanism is at the positive angle of attack).

[0036] Figure 7 This is a schematic diagram of the suction mechanism of the present invention;

[0037] Figure 8 This is a bottom view of the suction mechanism of the present invention;

[0038] Figure 9 This is a schematic diagram showing the arrangement of the front and rear wind speed sensing components.

[0039] Figure 10 yes Figure 9 A schematic diagram of the C-direction;

[0040] Figure 11 This is a structural schematic diagram of Embodiment 1 of the present invention (the angle of attack mechanism has an angle of attack of 0°).

[0041] Figure 12 This is a structural schematic diagram of Embodiment 1 of the present invention (the angle of attack mechanism is a positive angle of attack).

[0042] Figure 13 yes Figure 12 An enlarged schematic diagram of part B;

[0043] Figure 14 This is a three-dimensional structural schematic diagram of the boundary layer windbreak component of the present invention;

[0044] Figure 15 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0045] Figure 16 This is a front view of Embodiment 2 of the present invention;

[0046] Figure 17 This is another structural schematic diagram of Embodiment 2 of the present invention;

[0047] Figure 18 This is a schematic diagram showing the change in wind speed near the wall of the front panel with height;

[0048] Figure 19 This is a flowchart of the boundary layer thickness calculation method;

[0049] Figure 20 This is a flowchart illustrating the specific method for calculating the thickness of the boundary layer.

[0050] The labels in the diagram represent:

[0051] 1. Angle of attack mechanism; 11. Front plate; 12. Middle plate; 13. Rear plate; 14. Vortex; 15. Boundary layer; 2. Suction mechanism; 21. Suction channel; 22. Fan; 23. Connecting channel; 24. Suction perforated plate; 25. Pressure stabilizing chamber; 26. Honeycomb component; 27. Damping net; 28. Air duct; 3. Front wind speed sensing assembly; 31. High-sensitivity sensor; 32. Lifting drive component; 33. Low-sensitivity sensor; 4. Rear wind speed sensing assembly; 5. Boundary layer air-breaking assembly; 51. Guide fixing plate; 52. Elastic sheet; 53. Elastic rope; 54. Air-breaking mechanism 55. Zone; 551. Windbreak duct; 552. Through duct; 6. Lifting component; 61. Mounting base; 62. Lower hinge component; 63. Power source; 64. Drive rod; 65. Upper hinge component; 7. Boundary layer wind deflector assembly; 71. Transmission cable; 72. Rotating wheel assembly; 721. Rotating wheel bracket; 722. Transmission rod; 723. Rotating wheel; 73. Fixed pulley assembly; 731. Fixed pulley; 732. Fixed pulley bracket; 74. Turbine blade; 75. Wind deflector zone; 76. Transmission belt; 8. Return air inlet; 9. Wind tunnel test section. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of protection of the present invention. Example 1

[0053] Figures 2 to 10An embodiment of the wind tunnel test angle-of-attack adjustment device of the present invention is shown. The wind tunnel test angle-of-attack adjustment device includes an angle-of-attack mechanism 1. The upper surface of the angle-of-attack mechanism 1 is disposed within the wind tunnel test section 9. The angle-of-attack mechanism 1 includes a front plate 11, a middle plate 12, and a rear plate 13 that are sequentially movably connected along the airflow direction. The test object model is disposed on the middle plate 12 during the wind tunnel test. The present invention simulates the airflow environment under different angle-of-attack conditions by changing the angle of the angle-of-attack mechanism 1. In this embodiment, the angle-of-attack adjustment device also includes a suction mechanism 2, a front wind speed sensing component 3, and a rear wind speed sensing component 4. The suction mechanism 2 includes a suction channel 21 and a fan 22. Along the airflow direction, the inlet of the suction channel 21 is located upstream of the front plate 11, and the fan 22 is disposed within the suction channel 21. At this time, the fan 22 can draw the airflow from the front wall of the front plate 11 into the suction channel 21, thereby effectively destroying the vortex 14 generated at the front of the front plate 11, destroying the boundary layer 15, and reducing the thickness of the boundary layer 15. This makes the wind speed simulation more closely resemble the actual situation, effectively improving the accuracy of the wind tunnel test results. As a result, it can adapt to different test conditions and test models of different sizes, providing a foundation for aerodynamic research.

[0054] Meanwhile, the front wind speed sensor 3 is located at the end of the front plate 11, and the rear wind speed sensor 4 is located at the front of the rear plate 13. That is, by setting different sensor components on the front plate 11 and the rear plate 13 respectively, the wind speed and direction data of the angle of attack mechanism 1 at different test angles of attack can be effectively and quickly measured, ensuring the accurate detection and control of the subsequent boundary layer 15 thickness. Moreover, its structure is compact and occupies little space, realizing a high degree of integration of boundary layer 15 control and measurement functions.

[0055] like Figure 9 and Figure 10 As shown, both the front wind speed sensing assembly 3 and the rear wind speed sensing assembly 4 are equipped with a high-sensitivity sensor 31 and a lifting drive 32. The high-sensitivity sensor 31 is used to detect the flow velocity at different heights from the wall surface of the front plate 11 or the rear plate 13, so as to provide reliable and accurate experimental data for adjusting the thickness of the boundary layer 15 at different angles of attack. The lifting drive 32 can adjust the distance of the high-sensitivity sensor 31 from the wall surface, so as to facilitate the adjustment of the height of the high-sensitivity sensor 31 to the required thickness of the boundary layer 15. The front wind speed sensing assembly 3 is equipped with a low-sensitivity sensor 33, which is set close to the wall surface of the front plate 11. The low-sensitivity sensor 33 is located downstream of the suction channel 21, that is, close to the hinge point between the front plate 11 and the middle plate 12. The low-sensitivity sensor 33 detects the airflow direction of the front plate 11 near the wall surface when the fan 22 is working, so as to avoid the phenomenon that the wind and airflow direction of the front plate 11 near the wall surface are opposite due to the excessive power of the fan 22, and ensure the validity and accuracy of the test results. The high-sensitivity sensor 31 and the low-sensitivity sensor 33 are connected to the fan 22 and the lifting drive 32 through the control unit, and the effective automatic adjustment and control of the thickness of the boundary layer 15 is achieved by measuring the height of the boundary layer 15.

[0056] like Figure 5 and Figure 6 As shown, under negative angle of attack, after the suction mechanism 2 operates, the vortex 14 at the front end of the front plate 11 is disrupted, thus hindering the formation of the boundary layer 15 on the upper surfaces of the front plate 11 and the middle plate 12, effectively improving the accuracy of wind tunnel test results. However, under positive angle of attack, the suction mechanism 2 has a limited effect on the vortex 14 formed at the end of the front plate 11 and the front end of the middle plate 12. To solve the above problems, such as Figures 11 to 14 As shown, the present invention further includes a boundary layer wind-breaking component 5, which includes a guide fixing plate 51, an elastic sheet 52, and an elastic rope 53.

[0057] One end of the guide fixing plate 51 is fixed to the upper surface of the front plate 11, and the other end of the guide fixing plate 51 extends above the middle plate 12, that is, the boundary layer air-breaking assembly 5 is located at the connection between the front plate 11 and the middle plate 12. The guide fixing plate 51 is provided with multiple air-breaking channels 55, which are arranged along the length of the conductor fixing plate. Each air-breaking channel 55 is arranged through the airflow direction. The part of the air-breaking channel 55 covers beyond the hinge end of the front plate 11. The air-breaking channel 55 forms an air-breaking opening, causing the airflow close to the wall of the front plate 11 to gather towards the air-breaking opening, further reducing the thickness of the boundary layer 15 of the middle plate 12.

[0058] Meanwhile, multiple elastic plates 52 are positioned above the corresponding air-breaking slots 55. The excess portion of the air-breaking slots 55 and the elastic plates 52 together form an air-breaking zone 54, preventing the formation of vortices 14 at the front end of the middle plate 12. One end of the elastic plate 52 is fixedly connected to the guide plate 51, and the other end is fixed to the upper surface of the middle plate 12 via an elastic rope 53, further weakening the boundary layer 15 at the end of the front plate 11 and the front end of the middle plate 12. The elastic rope 53 has a certain stiffness; therefore, during the change of the positive angle of attack, the larger the positive angle of attack, the greater the change in length and tension of the elastic rope 53, and the greater the elastic deformation of the elastic plate 52. This results in different included angles formed by the bending of the elastic plate 52 under different positive angle of attack conditions, so that the weakening effect of the boundary layer 15 in each state is optimal.

[0059] At a negative angle of attack, the relative positions of the front plate 11 and the middle plate 12 are the same as at a 0-angle of attack. At this time, the boundary layer air-breaking component 5 is in close contact with the front plate 11 and has no effect. At a positive angle of attack, as the relative angle between the front plate 11 and the middle plate 12 changes, the elastic rope 53 constrains the end of the elastic sheet 52 to prevent it from displacing with the guide fixing plate 51. At this time, the elastic sheet 52 undergoes elastic deformation, and part of the airflow is forced to blow towards the wall surface through the air-breaking channel 55 under the constraint of the elastic sheet 52. That is, the setting of the air-breaking zone 54 not only hinders the formation of the vortex 14 at this position, but also further weakens the thickness of the wall layer.

[0060] Furthermore, the air-breaking channel 55 includes an interconnected guide channel 551 and a through channel 552. Along the airflow direction, the guide channel 551 is a square groove located at the front end of the guide fixing plate 51 to guide the airflow; the through channel 552 extends through the rear end of the guide fixing plate 51 and communicates with the air-breaking zone 54 to guide the airflow into the corresponding air-breaking zone 54. This further ensures that the airflow is effectively guided to the wall surface of the middle plate 12 through the air-breaking channel 55, so as to better achieve near-wall airflow interference under positive angle of attack conditions.

[0061] like Figure 5 and Figure 6 As shown, when the device is working, a vortex 14 will be formed at the airflow corner of the angle-of-attack mechanism 1, thereby forming a boundary layer 15 at the leeward position of the vortex 14. This results in a portion of the test model being located within the boundary layer 15, leading to a decrease in the accuracy of the test results. In this embodiment, as... Figure 8 As shown, there are multiple suction mechanisms 2 arranged perpendicular to the airflow direction. The inlets of the suction channels 21 of each suction mechanism 2 are connected through the same connecting channel 23. The connecting channel 23 is equipped with suction orifice plates 24 arranged along the length of the connecting channel 23. Its structure is compact and occupies little space, effectively ensuring that the airflow on the entire front wall of the front plate 11 in the wind tunnel test section 9 can be adsorbed into the suction channel 21. The outlet end of the suction channel 21 is located at the return air inlet 8 connected to the wind tunnel test section 9, so that the airflow can be re-entered and circulated back to the wind tunnel test section 9 for recycling and cost saving. The number of suction mechanisms 2 can be set according to the size of the wind tunnel and the test requirements.

[0062] Furthermore, such as Figure 7 As shown, the suction mechanism 2 also includes a pressure stabilizing chamber 25, a honeycomb component 26, and a damping mesh 27. The honeycomb component 26, damping mesh 27, and fan 22 are sequentially arranged along the suction direction of the suction channel 21 via a duct 28. The honeycomb component 26 forces the airflow to straighten, eliminating the circumferential velocity component, thereby reducing inlet flow distortion and uneven velocity distribution. The damping mesh 27 weakens large-scale eddies and turbulence on the suction side, transforming them into more uniform small-scale eddies. The combined use of the honeycomb component 26 and the damping mesh 27 ensures the stability of the airflow velocity distribution and improves the measurement accuracy and performance reliability of the suction mechanism 2. In this embodiment, the honeycomb component 26 is a honeycomb structure for forcing airflow straightening, and the damping mesh 27 is a porous metal mesh structure.

[0063] Meanwhile, the pressure stabilizing chamber 25 connects the suction orifice plate 24 and the duct 28. The vertical flow dimension of the pressure stabilizing chamber 25 is larger than the diameter of the duct 28, thus stabilizing the airflow pressure and homogenizing the airflow distribution. When the airflow enters from the suction orifice plate 24, pressure unevenness or fluctuations may occur due to the distribution of the orifice holes and the influence of local resistance. The pressure stabilizing chamber 25 provides a relatively large volume space, allowing the airflow velocity to decrease and the dynamic pressure to be converted into static pressure, thereby balancing pressure differences and reducing pulsation. At the same time, before the airflow enters the honeycomb structure 26 and the damping net 27, the pressure stabilizing chamber 25 can initially attenuate large-scale turbulence and vortices, improving the rectification effect of the honeycomb structure 26 and the damping net 27. Through the buffering effect of the pressure stabilizing chamber 25, the airflow can enter with a more uniform velocity and pressure distribution, reducing inlet flow distortion and providing a stable and reliable airflow foundation for the wind tunnel test section 9. The pressure stabilizing chamber 25 is located after the suction orifice plate 24 and before the honeycomb structure 26, playing a connecting role. It is used in conjunction with the honeycomb component 26 and the damping net 27 to ensure a stable airflow velocity distribution, thereby improving the measurement accuracy and performance reliability of the suction mechanism 2.

[0064] In this embodiment, the connecting channel 23 at the inlet of the suction channel 21 is located near the front plate 11; the suction perforation plate 24 has several through holes for air passage and intake. Air upstream of the front plate 11 is sequentially drawn through the suction perforation plate 24, the pressure stabilizing chamber 25, the honeycomb structure 26, and the damping mesh 27 to the return air inlet 8, and then re-enters the circulation system, blowing towards the wind tunnel test section 9. Preferably, a velocity and pressure sensor is installed inside the duct 28 to measure the suction velocity and pressure.

[0065] Furthermore, such as Figure 4 As shown, the angle-of-attack mechanism 1 also includes a lifting component 6, which includes a mounting base 61, a power source 63, and a drive rod 64. The lower end of the power source 63 is mounted to the mounting base 61 via a lower hinge component 62, and the upper end of the power source 63 is connected to an upper hinge component 65 via the drive rod 64. The upper hinge component 65 is hinged to the ends of the front plate 11, the middle plate 12, or the rear plate 13 respectively, to drive the angle-of-attack mechanism 1 to generate different angles of attack.

[0066] Furthermore, the bottom of the front plate 11, the middle plate 12 and the rear plate 13 are provided with reinforcing ribs, and the ends of the front plate 11, the middle plate 12 and the rear plate 13 are provided with hinge holes. The drive rod 64 and the upper hinge component 65 are matched between each other to form a hinge structure. The other end of the front plate 11 and the rear plate 13 that is not connected to the middle plate 12 is connected to the main structure of the wind tunnel through the hinge structure.

[0067] Preferably, in this embodiment, a trigonometric function motion relationship model is established based on the mechanical structure parameters of the angle of attack mechanism 1, and the motion position of the front and rear actuators (i.e. the motion position of the upper hinge component 65 connected to the drive rod 64) is analyzed and sent to the PLC controller in real time. By coordinating the position of several actuators of the angle of attack mechanism 1, the change of the incoming flow angle of attack of the test model is realized, such as the change of the angle of attack between -5° and +7°.

[0068] In this embodiment, the lifting drive component 32 includes an actuating rod and an actuator. The actuator is mounted on the bottom of the front plate 11 or the rear plate 13, and is driven by the actuating rod. The height sensor 31 is mounted on the actuating rod. The actuator can adjust the height of the actuating rod according to the instructions of the control unit, thereby adjusting the height of the height sensor 31.

[0069] In wind tunnel testing, the required thickness of the boundary layer 15 varies depending on the size of the test model. As the model size changes, the ideal boundary layer 15 thickness can vary from millimeters to centimeters. For example... Figure 18 and Figure 19 As shown, to meet the requirements for boundary layer 15 thickness control and calculation, this embodiment uses a boundary layer 15 thickness calculation method based on the wind tunnel test angle of attack adjustment device described above. The method includes the following steps:

[0070] Step 1), select the working sensor according to the test angle of attack adjusted by the angle of attack mechanism 1: When the angle of attack mechanism 1 is at a negative angle of attack, a vortex 14 is formed at the front end of the front plate 11, so that a boundary layer 15 is formed on the upper surface of the front plate 11 and the middle plate 12. At this time, the high-sensitivity sensor 31 in the front wind speed sensing component 3 at the front plate 11 is activated; when the angle of attack is positive, the thickness of the boundary layer 15 at the rear plate 13 is basically the same as the thickness of the boundary layer at the middle plate 12. At this time, the high-sensitivity sensor 31 in the rear wind speed sensing component 4 located at the rear plate 13 is activated; the low-sensitivity sensor 33 is always working.

[0071] Step 2), set the target boundary layer thickness H0 and the wind tunnel set velocity V0, and adjust the real-time power P of the fan to 20~50% of the rated power P0 of the fan to set the initial power. At this time, the initial power is significantly less than the rated power P0 of the fan, and the boundary layer 15 thickness usually does not reach the target boundary layer thickness H0; control the lifting drive 32 to adjust the height H of the working high-sensitivity sensor 31 to the target boundary layer thickness H0, and obtain the flow velocity V1 detected by the high-sensitivity sensor 31 and the flow velocity V2 detected by the low-sensitivity sensor 33.

[0072] Step 3) Adjust the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor 33 and / or the flow velocity V1 detected by the high-sensitivity sensor 31, so as to control the thickness of the boundary layer 15 to be at or below the target thickness H0 of the boundary layer, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan when the thickness of the boundary layer 15 cannot be controlled to be at or below H0, and complete the calculation of the thickness of the boundary layer 15.

[0073] The method of this invention obtains accurate and reliable measurement data through multi-parameter monitoring by a high-sensitivity sensor 31 and a low-sensitivity sensor 33. The real-time power P of the fan is adjusted based on the airflow direction detected by the low-sensitivity sensor 33 and / or the flow velocity detected by the high-sensitivity sensor 31, thereby controlling the boundary layer 15 thickness to be at or below the target boundary layer thickness H0, or obtaining the thinnest boundary layer thickness at the wind tunnel set flow velocity V0 or the fan rated power P0 when the boundary layer 15 thickness cannot be controlled at or below this level. In other words, the boundary layer 15 thickness can be quickly and accurately adjusted according to different test conditions, effectively solving the problem of difficult boundary layer 15 control in the prior art, further improving test efficiency and accuracy, providing accurate reference data for the test, and is easy to operate.

[0074] Further, in step 3), adjusting the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor 33 and / or the flow velocity V1 detected by the high-sensitivity sensor 31 includes:

[0075] like Figure 18 As shown, when V2 < 0, it means that the flow velocity V2 detected by the low-sensitivity sensor 33 is opposite to the wind tunnel set flow velocity V0. The real-time power P of the fan is reduced until V2 = 0, and the real-time power P of the fan is maintained at this state. Then, the height H of the corresponding high-sensitivity sensor 31 is raised by the lifting drive 32 until V1 = V0. At this time, the height H of the high-sensitivity sensor 31 is the thinnest boundary layer thickness under the wind tunnel set flow velocity V0. When V2 < 0, it indicates that the power of the fan 22 is too high, causing the wind speed near the wall of the front plate 11 detected by the low-sensitivity sensor 33 to reverse. This reduces the effectiveness and accuracy of the test results. The present invention effectively prevents the distortion of test data caused by excessive suction by reducing the real-time power P of the fan to V2 = 0. Then, by adjusting the height H of the high-sensitivity sensor 31, the flow velocity V1 of the high-sensitivity sensor 31 is adjusted to the wind tunnel set flow velocity V0. Thus, when the real-time power P of the fan cannot be controlled to adjust the thickness of the boundary layer 15 to H0 or below, the thinnest boundary layer thickness at the current V0 is calculated to provide wind tunnel test reference data.

[0076] When V2 > 0, it indicates that the flow velocity V2 detected by the low-sensitivity sensor 33 is in the same direction as the wind tunnel set flow velocity V0. Compare the relationship between the flow velocity V1 detected by the high-sensitivity sensor 31 and the wind tunnel set flow velocity V0. Based on the relationship between V1 and V0, determine whether to adjust the real-time power P of the fan to control the boundary layer 15 thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan.

[0077] Furthermore, determining whether to adjust the real-time power P of the fan based on the relationship between V1 and V0 includes:

[0078] When V1 = V0, it means that the target thickness H0 of the boundary layer has been achieved when the real-time power P of the fan is at the initial set value (such as 20~50% of the rated power P0 of the fan). At this time, without adjusting the real-time power P of the fan, the height H of the high-sensitivity sensor 31 is at or below H0.

[0079] When V1 < V0, the real-time power P of the blower is slowly increased. During the increase of the real-time power P, the suction gradually strengthens, and the thickness of the boundary layer 15 gradually decreases. If, during the increase of the real-time power P, P < P0 and V2 > 0, it indicates that the real-time power P of the blower has not reached the rated power P0 of the blower, and the airflow at the low-sensitivity sensor 33 is not reversed. In this case, the real-time power P of the blower can be continuously increased until V1 = V0. At this point, it is determined that the thickness of the boundary layer 15 is controlled to the target thickness H0, indicating that the thickness of the boundary layer 15 has reached the target value, thereby effectively solving the problem of difficult control of the boundary layer 15 and further improving the efficiency and accuracy of the test. If, during the process of increasing the real-time power P of the wind turbine, P = P0 and V2 > 0, it indicates that the real-time power P of the wind turbine has reached the rated power P0, and the airflow at the low-sensitivity sensor 33 is not reversed, but the boundary layer 15 thickness has not reached the target boundary layer thickness H0. At this time, the height H of the high-sensitivity sensor 31 is the thinnest boundary layer thickness under the rated power P0 of the wind turbine. This thinnest boundary layer thickness can provide data support for the judgment and evaluation of wind tunnel tests, that is, to judge and evaluate whether the test results under this thinnest boundary layer thickness are referential and necessary. If, during the process of increasing the real-time power P of the wind turbine, P = P0 and V2 = 0, it indicates that the real-time power P of the wind turbine has reached the rated power P0, and there is no airflow at the low-sensitivity sensor 33. At this time, the increase of the real-time power P of the wind turbine should be stopped to avoid generating reverse airflow. The height H of the high-sensitivity sensor 31 is the thinnest boundary layer thickness under the wind tunnel set flow velocity V0, that is, the target boundary layer thickness H0.

[0080] like Figure 20 As shown, the boundary layer thickness calculation method of the present invention includes the following specific steps:

[0081] (a) Initial setup phase

[0082] The working sensor is selected according to the test angle of attack adjusted by the angle of attack mechanism 1. When the angle of attack is negative, the high-sensitivity sensor 31 in the front wind speed sensing component 3 is activated; when the angle of attack is positive, the high-sensitivity sensor 31 in the rear wind speed sensing component 4 is activated; the low-sensitivity sensor 33 is always working.

[0083] Input the target boundary layer thickness H0 and the wind tunnel set flow velocity V0, and adjust the real-time power P of the wind turbine to 20-50% of the rated power P0 of the wind turbine to provide initial values ​​for iteration; control the corresponding lifting drive 32 to adjust the height H of the working high-sensitivity sensor 31 to the target boundary layer thickness H0. Read the flow velocity V1 detected by the high-sensitivity sensor 31 and the flow velocity V2 detected by the low-sensitivity sensor 33 at this time.

[0084] (II) Judgment and Adjustment Stage

[0085] Different processing is performed based on the direction of V2. When V2 < 0, the real-time power P of the fan is reduced until V2 = 0, and the fan operates at the same real-time power P. Then, the height H of the corresponding high-sensitivity sensor 31 is raised by the lifting drive 32 until V1 = V0. At this time, the height H of the high-sensitivity sensor 31 is the thinnest boundary layer thickness under the set flow velocity V0 in the wind tunnel. When V2 > 0, the relationship between V1 and V0 is further determined.

[0086] When V1 = V0, without adjusting the real-time power P of the fan, the height H of the high-sensitivity sensor 31 is at or below H0, and the boundary layer thickness meets the requirements. When V1 < V0, the real-time power P of the fan is increased. During the increase: if P < P0 and V2 > 0, the real-time power P of the fan is continuously increased until V1 = V0. At this point, the boundary layer thickness H is determined to be controlled at the target boundary layer thickness H0. If, during the increase, V2 remains greater than 0 and P reaches P0, the height H of the high-sensitivity sensor 31 at this point is recorded as the thinnest boundary layer thickness under the rated power P0 of the fan. If, during the increase, V2 becomes 0, the increase of the real-time power P of the fan is stopped. At this point, the height H of the high-sensitivity sensor 31 is the thinnest boundary layer thickness under the set flow velocity V0 of the wind tunnel.

[0087] This invention can automatically adjust the real-time power of the fan by setting the H0 value, thereby controlling the boundary layer thickness below the target value. Especially for small-sized test models, which typically require a thin boundary layer, this invention can effectively meet the testing requirements of small-sized models.

[0088] Under extreme conditions, when testing the wind tunnel's maximum boundary layer control capability (15), H0 can be set to a minimum value. The system will attempt to achieve the target by increasing the power of the wind turbine (22). When P0 is reached, the boundary layer thickness at this point is recorded to provide data support for wind tunnel performance evaluation.

[0089] Example 2

[0090] Figures 15 to 17 Another embodiment of the wind tunnel test angle of attack adjustment device of the present invention is shown. This embodiment is basically the same as the previous embodiment, except that this embodiment also includes a boundary layer wind deflector assembly 7. The boundary layer wind deflector assembly 7 includes a transmission cable 71, a rotating wheel assembly 72, a fixed pulley assembly 73, and deflector blades 74. The rotating wheel assembly 72 is installed on the front plate 11, and the fixed pulley assembly 73 is installed on the middle plate 12. The rotating wheel assembly 72 and the fixed pulley assembly 73 are located in the same plane along the airflow direction. One end of the transmission cable 71 is fixed to the middle plate 12, and the other end of the transmission cable 71 is sequentially wound around the fixed pulley assembly 73 and the rotating wheel assembly 72 and fixed inside the rotating wheel assembly 72. The deflector blades 74 are arranged facing the airflow direction, and there are multiple deflector blades 74. The multiple deflector blades 74 are arranged perpendicular to the airflow direction and installed on the rotating wheel assembly 72. When the angle of attack is positive, the spoiler blade 74 rotates downward to form a turbulence zone 75 below it. This forces the airflow towards the wall of the middle plate 12, disrupts the vortex 14, and weakens the boundary layer thickness. This invention can automatically adjust the angle of the spoiler blade 74 according to the change in angle of attack to achieve the best boundary layer 15 weakening effect. Moreover, it does not require an additional power source 63, has a simple structure, and occupies little space.

[0091] In this embodiment, the rotating wheel assembly 72 includes two rotating wheel supports 721, a transmission rod 722, and a rotating wheel 723. The two rotating wheel supports 721 are respectively mounted on the upper surfaces of the front plate 11 on both sides perpendicular to the airflow direction. The transmission rod 722 is rotatably connected between the two rotating wheel supports 721, and the rotating wheels 723 are fixedly mounted at both ends of the transmission rod 722. Multiple turbulence-inducing blades 74 are arranged along the length of the transmission rod 722. The fixed pulley assembly 73 includes a fixed pulley 731 and two fixed pulley supports 732. The two fixed pulley supports 732 are respectively mounted on the upper surfaces of the middle plate 12 on both sides perpendicular to the airflow direction. The fixed pulley 731 is rotatably mounted on the fixed pulley supports 732.

[0092] At a negative angle of attack, the relative positions of the front plate 11 and the middle plate 12 are the same as at a 0-angle-of-attack state, and the boundary layer spoiler assembly 7 is inactive. At a positive angle of attack, as the relative angle between the front plate 11 and the middle plate 12 changes, the drive cable 71 pulls the rotating wheel 723 to rotate, which in turn drives the drive rod 722 and the spoiler blades 74 to rotate, thereby interfering with the airflow near the wall and forcing it to flow closer to the wall, thus disrupting the formation of the vortex 14 and weakening the thickness of the boundary layer 15.

[0093] Furthermore, such as Figure 17As shown, to accommodate the needs of large-scale test models, the deflector blades 74 are arranged in three layers along the height direction. The number of rotating wheel assemblies 72 is the same as the number of deflector blades 74, and they are arranged in a one-to-one correspondence. Adjacent rotating wheel assemblies 72 rotate synchronously via a transmission belt 76 or a gear set. One set of rotating wheel assemblies 72 is driven and connected to a fixed pulley assembly 73 via a transmission cable 71. In other embodiments, the number of layers of deflector blades 74 can be set according to the test model of different sizes; for example, the deflector blades 74 can also be set in two layers, four layers, etc. In this embodiment, the transmission belt 76 can be a belt, chain, etc.

[0094] Preferably, the rotating wheel assembly 72 and the fixed pulley assembly 73 are arranged symmetrically with the connection between the front plate 11 and the middle plate 12 as the center, so as to facilitate the boundary layer wind deflector assembly 7 to adjust the deflector blades 74 according to the angle of attack.

[0095] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A wind tunnel test angle of attack adjustment device, comprising an angle of attack mechanism disposed in the wind tunnel test section, the angle of attack mechanism comprising a front plate, a middle plate, and a rear plate sequentially and movably connected along the airflow direction, characterized in that, It also includes a suction mechanism with the inlet located upstream of the front panel, a front wind speed sensing component located at the end of the front panel, and a rear wind speed sensing component located at the front of the rear panel. The suction mechanism includes a suction channel and a fan located in the suction channel. Both the front and rear wind speed sensing components include high-sensitivity sensors that detect the flow velocity at different heights from the wall surface of the front or rear panel, and a lifting drive component that adjusts the distance between the high-sensitivity sensor and the wall surface. The front wind speed sensing component also includes a low-sensitivity sensor that detects the airflow direction near the wall surface of the front panel. The low-sensitivity sensor is located downstream of the suction channel. The high-sensitivity sensor and the low-sensitivity sensor are connected to the fan and the lifting drive component through a control unit. When the angle of attack mechanism is at a negative angle of attack, the high-sensitivity sensor in the front wind speed sensing component is activated; when the angle of attack is positive, the high-sensitivity sensor in the rear wind speed sensing component is activated; the low-sensitivity sensor is always working. The flow velocity V1 detected by the high-sensitivity sensor and the flow velocity V2 detected by the low-sensitivity sensor are obtained. The real-time power P of the fan is adjusted according to the direction of the flow velocity V2 detected by the low-sensitivity sensor and / or the flow velocity V1 detected by the high-sensitivity sensor, so as to control the boundary layer thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan when the boundary layer thickness cannot be controlled to be at or below H0.

2. The wind tunnel test angle of attack adjustment device according to claim 1, characterized in that, It also includes a boundary layer wind-breaking assembly that weakens the boundary layer at a positive angle of attack. The boundary layer wind-breaking assembly includes a guide fixing plate, an elastic sheet, and an elastic rope. One end of the guide fixing plate is fixed to the upper surface of the front plate, and the other end extends above the middle plate. The guide fixing plate has multiple wind-breaking slots that are arranged through the airflow direction. The elastic sheet consists of multiple elastic sheets corresponding to the upper surface of the wind-breaking slots to form a wind-breaking zone that prevents vortices from forming at the front end of the middle plate. One end of the elastic sheet is fixedly connected to the guide fixing plate, and the other end is fixed to the upper surface of the middle plate by the elastic rope.

3. The wind tunnel test angle of attack adjustment device according to claim 1, characterized in that, It also includes a boundary layer wind deflector assembly that weakens the boundary layer at a positive angle of attack. The boundary layer wind deflector assembly includes a drive cable, a rotating wheel assembly mounted on the front plate, a fixed pulley assembly mounted on the middle plate, and deflector blades arranged in the direction of airflow. The rotating wheel assembly and the fixed pulley assembly are located in the same plane along the direction of airflow. One end of the drive cable is fixed to the middle plate, and the other end is sequentially wound around the fixed pulley assembly and the rotating wheel assembly. A plurality of deflector blades are arranged perpendicular to the direction of airflow and are mounted on the rotating wheel assembly. The deflector blades rotate downward at a positive angle of attack to form a wind deflector zone that forces the airflow to flow toward the wall of the middle plate and disrupts the vortex.

4. The wind tunnel test angle of attack adjustment device according to claim 3, characterized in that, The deflector blades are at least two layers, and the multiple layers of deflector blades are arranged along the height direction. The number of rotating wheel assemblies is the same as the number of deflector blades and they are arranged in a one-to-one correspondence. Adjacent rotating wheel assemblies are synchronized by a transmission belt or gear set, and one group of rotating wheel assemblies is driven to the fixed pulley assembly by the transmission cable.

5. The wind tunnel test angle of attack adjustment device according to any one of claims 1 to 4, characterized in that, The suction mechanism consists of multiple sets, which are arranged perpendicular to the airflow direction. The inlets of the suction channels of each suction mechanism are connected through the same connecting channel. The connecting channel is provided with suction orifice plates arranged along the length of the connecting channel. The outlet end of the suction channel is located at the return air inlet connected to the wind tunnel test section.

6. The wind tunnel test angle of attack adjustment device according to claim 5, characterized in that, The suction mechanism also includes a pressure stabilizing chamber for stabilizing and homogenizing the airflow, a honeycomb structure for forcing the airflow to be straightened, and a damping mesh for weakening large-scale eddy turbulence on the suction side. The honeycomb structure, damping mesh, and fan are arranged sequentially along the suction direction of the suction channel through a duct. The pressure stabilizing chamber is connected between the suction orifice plate and the duct, and the vertical flow dimension of the pressure stabilizing chamber is larger than the diameter of the duct.

7. The wind tunnel test angle of attack adjustment device according to any one of claims 1 to 4, characterized in that, The angle-of-attack mechanism also includes a lifting component that drives the plate to change its angle. The lifting component includes a mounting base, a power source, and a drive rod. The lower end of the power source is mounted on the mounting base via a lower hinge component, and the upper end of the power source is connected to an upper hinge component via the drive rod. The upper hinge component is hinged to the end of the front plate, the middle plate, or the rear plate, respectively.

8. A method for calculating the boundary layer thickness based on the wind tunnel test angle-of-attack adjustment device according to any one of claims 1 to 7, characterized in that, The method includes the following steps: Step 1), select the working sensor according to the test angle of attack adjusted by the angle of attack mechanism: when the angle of attack mechanism is at a negative angle of attack, the high-sensitivity sensor in the front wind speed sensing component is activated; when the angle of attack is positive, the high-sensitivity sensor in the rear wind speed sensing component is activated; the low-sensitivity sensor is always working. Step 2), set the target boundary layer thickness H0 and the wind tunnel set velocity V0, adjust the real-time power P of the fan to 20~50% of the rated power P0 of the fan, and control the lifting drive to adjust the height H of the working high-sensitivity sensor to the target boundary layer thickness H0, and obtain the velocity V1 detected by the high-sensitivity sensor and the velocity V2 detected by the low-sensitivity sensor. Step 3) Adjust the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor and / or the flow velocity V1 detected by the high-sensitivity sensor, so as to control the boundary layer thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan when the boundary layer thickness cannot be controlled to be at or below H0.

9. The method for calculating the boundary layer thickness of the wind tunnel test angle-of-attack adjustment device according to claim 8, characterized in that, In step 3), adjusting the real-time power P of the fan according to the direction of the flow velocity V2 detected by the low-sensitivity sensor and / or the flow velocity V1 detected by the high-sensitivity sensor includes: When V2 < 0, reduce the real-time power P of the fan until V2 = 0, and maintain the real-time power P of the fan in this state. Then, raise the height H of the corresponding high-sensitivity sensor through the lifting drive until V1 = V0. At this time, the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the set flow velocity V0 of the wind tunnel. When V2 > 0, compare the relationship between the flow velocity V1 detected by the high-sensitivity sensor and the wind tunnel set flow velocity V0. Based on the relationship between V1 and V0, determine whether to adjust the real-time power P of the fan to control the boundary layer thickness to be at or below the target boundary layer thickness H0, or to obtain the thinnest boundary layer thickness under the wind tunnel set flow velocity V0 or the rated power P0 of the fan.

10. The method for calculating the boundary layer thickness of the wind tunnel test angle-of-attack adjustment device according to claim 9, characterized in that, The step of determining whether to adjust the real-time power P of the fan based on the relationship between V1 and V0 includes: When V1 = V0, without adjusting the real-time power P of the fan, the height H of the high-sensitivity sensor will be at or below H0. When V1 < V0, the real-time power P of the fan is increased. During the process of increasing the real-time power P, if P < P0 and V2 > 0, the real-time power P of the fan is continuously increased until V1 = V0. At this time, the boundary layer thickness H is determined to be controlled as the target boundary layer thickness H0. If P = P0 and V2 > 0, the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the rated power P0 of the fan. If P = P0 and V2 = 0, the increase of the real-time power P of the fan is stopped. At this time, the height H of the high-sensitivity sensor is the thinnest boundary layer thickness under the set flow velocity V0 of the wind tunnel.

Images