Boundary layer control device and wind tunnel

Abstract

The embodiment of the application provides a boundary layer control device and a wind tunnel. The boundary layer control device comprises a multi-stage suction system and a blowing system; the multi-stage suction system is used for sucking away a boundary layer airflow located at the edge of a main airflow, and the multi-stage suction system specifically comprises a first-stage suction system, at least two intermediate suction systems and a tail-stage suction system arranged in sequence along a first direction (X), and the first-stage suction system is connected with an air outlet; the blowing system is arranged between two adjacent intermediate-stage systems, and the blowing system is used for providing a target airflow along the first direction (X) to the edge of the airflow, and the flow rate of the target airflow is greater than that of the boundary layer airflow. The boundary layer control device of the automobile wind tunnel provided by the application adopts the multi-stage suction system and the blowing system, realizes multi-stage control on the boundary layer of the wind tunnel, effectively controls the regeneration of the boundary layer, suppresses the increase of the boundary layer thickness, makes the test environment of the wind tunnel closer to the case that a vehicle drives on an actual road, and improves the accuracy of test results.

Description

Technical Field

[0001] This application relates to the field of wind tunnel testing technology, and in particular to a boundary layer control device and a wind tunnel. Background Technology

[0002] Wind tunnel testing is a crucial method for evaluating vehicle performance during automotive development. It simulates real-world driving environments to test a vehicle's aerodynamic performance. In a wind tunnel, as airflow passes over the tunnel floor, the air velocity in the layer immediately below the floor drops to zero. From the floor away, the air velocity gradually increases until it reaches the set velocity. This thin layer, ranging from zero velocity to 99% of the set velocity, is called the boundary layer. In traditional wind tunnel testing, a boundary layer forms on the tunnel floor, thickening as the airflow travels further. However, in real-world driving, the boundary layer does not exist. Therefore, in wind tunnel testing, the boundary layer should be eliminated as much as possible.

[0003] Currently, existing wind tunnel boundary layer control schemes mainly include: raising the ground, horizontal suction systems, vertical suction systems, and combinations of horizontal and vertical suction systems with a blowing system. Existing technologies only perform boundary layer suction or supplemental high-speed airflow in an area a short distance from the vehicle's nose when eliminating the boundary layer, lacking further measures to suppress it. Once the airflow passes through this suction area, the boundary layer immediately regenerates, causing a deviation between the test environment and actual vehicle driving conditions, thus leading to inaccurate test data. Utility Model Content

[0004] This application provides a boundary layer control device and a wind tunnel, which aims to improve the regeneration problem of the ground boundary layer in automotive wind tunnel testing.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a boundary layer control device for a wind tunnel, the wind tunnel including: an air outlet, the air outlet being used to spray a main airflow along a first direction (X) into the wind tunnel, the boundary layer control device including: a multi-stage suction system and a blowing system;

[0007] The multi-stage suction system is used to remove the boundary layer airflow located at the edge of the main airflow. The multi-stage suction system includes a first-stage suction system, at least two intermediate suction systems and a tail-stage suction system arranged sequentially along the first direction (X). The first-stage suction system is connected to the air outlet.

[0008] The blowing system is disposed between two adjacent intermediate stage systems. The blowing system is used to provide a target airflow along the first direction (X) to the airflow edge. The velocity of the target airflow is greater than the velocity of the boundary layer airflow.

[0009] Specifically, the air outlet is the starting point where the target airflow enters the wind tunnel, and the boundary layer is in its initial formation stage. At this time, the boundary layer thickness is the thinnest and its influence range is the smallest. By connecting the first-stage suction system to the air outlet, the boundary layer airflow can be directly removed at the source of boundary layer generation, preventing the initial boundary layer from continuously accumulating and thickening as the main airflow flows along the first direction (X), thus reducing the difficulty of subsequent boundary layer control. When the main airflow flows along the first direction (X), the boundary layer will continue to be generated. The initial boundary layer is treated by the first-stage suction system, at least two intermediate-stage suction systems treat the boundary layer newly formed during the flow of the main airflow, and the residual boundary layer downstream of the main airflow is treated by the tail-stage suction system. This achieves full-path coverage control of the boundary layer, thoroughly reducing the total amount of ground boundary layer in the wind tunnel and improving the accuracy of experimental data.

[0010] Simultaneously, the blowing system provides a high-speed target airflow to the portion near the wind tunnel surface, which accelerates the low-speed boundary layer airflow, reduces the velocity difference between the boundary layer airflow and the main airflow, improves the uniformity of velocity distribution at the edge of the main airflow, and further enhances the overall uniformity of the wind tunnel flow field. The multi-stage suction system and the blowing system work together to overcome the limitations of single suction or single blowing techniques, achieving dual control of the ground boundary layer, maximizing the elimination of the ground boundary layer, providing a more precise experimental environment for vehicle performance testing, and ensuring the reliability of test data.

[0011] Optionally, the blowing system is provided with a flat blowing port for blowing out the target airflow.

[0012] Specifically, when the target airflow is ejected from the flat-shaped nozzle, it forms a wider airflow coverage band. Compared to nozzles with other cross-sections such as circles, the flat structure allows for a more uniform distribution of the ejected airflow at the same flow rate, avoiding excessively strong or weak airflow in localized areas and improving the overall uniformity of boundary layer control. Simultaneously, the flat design allows the target airflow to integrate into the main airflow more smoothly, with its outlet direction more closely aligned with the flow direction of the main airflow (the first direction (X)). Furthermore, the target airflow is more dispersed laterally, avoiding turbulence or eddies caused by excessively strong localized airflow, thus reducing the impact on the stability of the target airflow. Moreover, the target airflow has a thinner thickness and a wider width, resulting in a larger contact area with the boundary layer airflow. Since the target airflow velocity is greater than the boundary layer airflow velocity, the larger contact area promotes more thorough momentum transfer between the two, allowing the boundary layer airflow to be accelerated to near the velocity of the main airflow more quickly.

[0013] Optionally, the boundary layer control device further includes: an air collection system and a return air device;

[0014] Both the first-stage suction system and the last-stage suction system are connected to the return air device, and the intermediate-stage suction system is connected to the gas collection system.

[0015] The gas collection system is connected to the return air device, which includes a return air inlet connected to the wind tunnel. The return air device is used to collect the boundary layer airflow drawn away by the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system, and to spray the boundary layer airflow towards the upstream position of the wind tunnel through the return air inlet.

[0016] Specifically, in traditional boundary layer control devices, the extracted boundary layer airflow has two flow directions. One is direct discharge to the outside of the wind tunnel. To maintain the total airflow within the wind tunnel, the outlet needs to continuously draw in "fresh air" from the outside and pressurize it before ejecting it, resulting in high energy consumption at the outlet. In the other case, the extracted boundary layer airflow returns to the downstream position of the wind tunnel, circulates through the flow channel, and then returns to the area where the extraction system is located. In this application, the return air outlet sends the extracted boundary layer airflow back to the upstream position of the wind tunnel. It can directly integrate into the main airflow without going through the flow channel, resulting in a faster response speed. Furthermore, it forms an airflow circulation inside the wind tunnel. The outlet only needs to replenish a small amount of airflow lost due to leakage or testing, without continuously providing a large amount of fresh air, significantly reducing the operating load and energy consumption of the outlet.

[0017] Optionally, the gas collection system includes: a gas collection box, a gas collection pipe, a rotating unit, and a turntable;

[0018] The gas collection box has multiple gas collection ports, which are connected to the intermediate stage suction system. The bottom of the gas collection box is connected to the rotating unit, the bottom of the rotating unit is movably connected to the gas collection pipe, and the gas collection pipe is connected to the return air device.

[0019] The turntable is a disc with a rectangular opening along the diameter direction, and the two intermediate suction systems are respectively installed at both ends of the rectangular opening along the first direction (X).

[0020] Specifically, multiple gas collection ports correspond one-to-one with the intermediate-stage suction system, ensuring that the airflow from each intermediate-stage suction system can enter the gas collection box through an independent channel, improving gas collection efficiency. The bottom of the gas collection box is connected to a rotating unit, which is movably connected to the gas collection pipe. This allows the rotating structure to drive the gas collection box and intermediate suction system to rotate without moving the gas collection pipe, reducing pipe wear. Simultaneously, it ensures that the intermediate-stage suction system can meet the suction direction requirements under different testing conditions.

[0021] A rectangular opening is positioned along the diameter of the turntable, forming an airflow channel along the first direction (X). An intermediate-stage suction system is installed at both ends of the rectangular opening. During suction, it guides the boundary layer airflow along the long side of the rectangular opening (the first direction (X)), preventing vortices from forming due to chaotic direction before entering the suction system, ensuring the boundary layer airflow is removed in a more orderly manner. When the main airflow flows along the first direction (X), the front-end suction treats the newly formed boundary layer upstream, while the rear-end suction treats any remaining boundary layer not completely removed, avoiding suction blind spots in the middle region. Simultaneously, the symmetrical arrangement balances the suction pressure at both ends, ensuring the boundary layer airflow is evenly removed laterally, improving the uniformity and thoroughness of boundary layer airflow removal.

[0022] Optionally, the end of the first-stage suction system and the tail-stage suction system closest to the turntable is a first arc surface, the first arc surface is at the same center as the turntable, and the radius of the first arc surface is greater than the radius of the turntable;

[0023] The end of any intermediate-stage suction system furthest from the center of the turntable is a second arc surface, which is the same as the center of the turntable, and the radius of the second arc surface is the same as the radius of the turntable.

[0024] Specifically, when the turntable rotates with the rotating unit, if the ends of the first-stage and last-stage suction systems closest to the turntable are flat or non-concentric arc surfaces, their edges may collide with these systems during rotation, causing the turntable to malfunction or resulting in component wear. However, the first arc surface coincides with the center of the turntable, ensuring that its edge and the first arc surface maintain a concentric circular trajectory during rotation. Furthermore, the radius of the first arc surface is larger than the radius of the turntable, further ensuring a stable gap between them. This design geometrically eliminates the risk of collision between the turntable and the first-stage and last-stage suction systems during rotation, guaranteeing smooth rotational movement and achieving interference-free rotational cooperation between the turntable and these systems, thus ensuring the structural safety and operational flexibility of the device.

[0025] The first and second arc surfaces, along with the turntable, share the same center, ensuring that the first, intermediate, and final stage suction systems and the turntable form a concentric circle structure in spatial layout, resulting in higher relative positional accuracy of each component. This structural consistency reduces the impact of installation errors on suction performance.

[0026] Optionally, the upper surfaces of the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system, as well as the upper surface of the turntable, are all located on the same plane.

[0027] Specifically, when the main airflow flows along the internal surface of the wind tunnel, if there is a height difference between the upper surfaces of different components, steps are formed. The presence of these steps will generate noise during the main airflow process, which is detrimental to the conduct of wind noise tests. At the same time, when the low-speed boundary layer encounters a step, it will detach from the surface due to abrupt changes in the flow path, forming local turbulence and resulting in uneven velocity distribution in that region. The "coplanar upper surface" design completely eliminates this height difference. The first-stage suction system, intermediate-stage suction system, and tail-stage suction system form a continuous and flat flow interface with the upper surface of the turntable. When the main airflow flows along this interface, there is no physical obstruction or abrupt change in the path. The boundary layer airflow can always adhere to the surface and flow stably, avoiding turbulence interference caused by steps, maintaining the flow stability of the boundary layer airflow and the main airflow, further improving the overall uniformity of the wind tunnel flow field, and avoiding the distortion of test data caused by surface unevenness.

[0028] Optionally, the first-stage suction system, the intermediate-stage suction system, and the last-stage suction system are all equipped with an anemometer, which is used to measure the velocity of the boundary layer airflow.

[0029] Specifically, the anemometer's function is to capture the boundary layer airflow velocity in the first-stage, intermediate-stage, and final-stage suction systems in real time, and adjust the power of the corresponding suction systems accordingly to ensure that the suction effect matches the actual boundary layer state. This enhances the scientific rigor and precision of wind tunnel testing, provides crucial evidence for validating test data and tracing problems, and ensures the reliability of automotive aerodynamic performance test results.

[0030] Optionally, the boundary layer control device further includes a control system, which is connected to the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system to achieve centralized control of the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system.

[0031] Specifically, the primary suction system, intermediate suction system, and tail suction system need to work together. If decentralized control (independent adjustment of each stage) is adopted, parameter conflicts are likely to occur. For example, if the primary suction system is too strong, the intermediate suction system will not have enough airflow to handle, or if it is too weak, the intermediate suction system will be overburdened, thus disrupting the overall control rhythm.

[0032] Centralized control of the system enables comprehensive global parameter management: through a pre-set collaborative algorithm, the optimal parameter combination for the primary, intermediate, and final stages of the suction system is calculated in one go based on experimental requirements and executed synchronously. Simultaneously, based on the full-process data fed back from the anemometer, the parameters of all relevant suction systems can be adjusted in a coordinated manner, avoiding new imbalances caused by local adjustments. Furthermore, it reduces operational complexity and the cost of manual intervention; standardized parameter settings reduce human error and improve the repeatability and reliability of experimental results.

[0033] Secondly, embodiments of this application provide an automotive wind tunnel, the automotive wind tunnel including the boundary layer control device described in any of the first aspects. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a boundary layer control device provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the first-stage suction system structure provided in an embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the intermediate-stage suction system structure provided in one embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the tail-stage suction system provided in one embodiment of this application;

[0038] Figure 5 This is a schematic diagram of the air blowing system structure provided in one embodiment of this application;

[0039] Figure 6 This is a schematic diagram of the air inlet structure of an air blowing system provided in an embodiment of this application;

[0040] Figure 7 This is a schematic diagram of the gas collection system structure provided in an embodiment of this application;

[0041] Figure 8 This is a schematic diagram of the control system structure provided in an embodiment of this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1-Multi-stage suction system, 10-First-stage suction system, 100-First-stage suction plate, 101-First-stage suction box, 102-First-stage anemometer, 103-First-stage suction pipe, 104-First-stage suction fan, 11-Intermediate-stage suction system, 110-Intermediate-stage suction plate, 111-Intermediate-stage suction box, 112-Intermediate-stage anemometer, 113-Intermediate-stage suction branch pipe, 114-Intermediate-stage suction fan, 115-Intermediate-stage suction fan outlet, 12-Tail-stage suction system, 120-Tail-stage suction plate, 121-Tail-stage suction box, 122-Tail-stage anemometer, 123-Tail-stage suction branch pipe 124-Tail-stage suction main pipe, 125-Tail-stage suction fan; 2-Blowing system, 20-Blowing outlet, 21-Blowing box shell, 22-Blowing branch pipe, 23-Blowing main pipe, 24-Blowing fan, 25-Blowing anemometer, 26-Blowing inlet; 3-Gas collection system, 30-Gas collection box, 31-Gas collection port, 32-Rotating unit, 33-Gas collection pipe; 4-Air outlet; 5-Return air device, 50-Return air port; 6-Control system, 60-Main control computer, 61-First control PLC, 62-First control PLC; 7-Airflow collection port; 8-Test section, 80-Test section ground. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0045] In a first aspect, embodiments of this application provide a boundary layer control device for a wind tunnel. The wind tunnel includes an outlet 4, which is connected to the wind tunnel and is used to spray airflow along a first direction (X) into the wind tunnel. The boundary layer control device 1 includes a multi-stage suction system 1 and a blowing system 2. The multi-stage suction system 1 is used to remove the boundary layer airflow located at the edge of the airflow. The multi-stage suction system 1 specifically includes a first-stage suction system 10, at least two intermediate suction systems 11, and a tail-stage suction system 12 arranged sequentially along the first direction (X). The first-stage suction system 10 is connected to the outlet 4. The blowing system 2 is arranged between two adjacent intermediate systems 11 and is used to provide a target airflow along the first direction (X) to the edge of the airflow. The velocity of the target airflow is greater than the velocity of the boundary layer airflow.

[0046] The boundary layer control device provided in this application adopts a multi-stage suction system 1 and a blowing system 2 to achieve multi-stage control of the wind tunnel boundary layer, effectively control boundary layer regeneration, suppress the increase of boundary layer thickness, make the wind tunnel test environment closer to the situation when a vehicle is driving on a real road, and improve the accuracy of test results.

[0047] Example 1

[0048] The multi-stage suction system 1 specifically includes a first-stage suction system 10, an intermediate-stage suction system 11, and a final-stage suction system 12. The intermediate-stage suction system 11 specifically includes a second-stage suction system and a third-stage suction system. In practical applications, the specific structural form and connection relationship of the multi-stage suction system are as follows:

[0049] For details on the primary suction system 10, please refer to [link / reference]. Figure 2 It includes: a primary suction plate 100, a primary suction box 101, a primary suction pipe 103, and a primary suction fan 104; wherein, the primary suction plate 100 is a low-noise perforated plate; the primary suction box 101 is a hollow rectangular cavity, the top of which is sealed to the primary suction plate 100, and the bottom is connected to the primary suction pipe 103 through a flange; the primary suction fan 104 is a variable frequency centrifugal fan, installed in the middle of the primary suction pipe 103.

[0050] For details on the intermediate suction system 11, please refer to [link / reference]. Figure 3 It includes a two-stage suction system and a three-stage suction system. The two-stage suction system and the three-stage suction system have the same structure, including: suction plate 110, suction box 111, suction branch pipe 113 and suction fan 114; wherein, suction plate 110 has the same structure as the first-stage suction plate 100; suction box 111 is a hollow cavity, with two suction branch pipes 113 symmetrically connected to the bottom; each suction branch pipe 113 is equipped with an anemometer 112, and each is equipped with a suction fan 114 at the end, and the suction fan outlet 115 is open.

[0051] For details on the tail-stage suction system 12, please refer to [link / reference]. Figure 4 It includes: a tail-stage suction plate 120, a tail-stage suction box 121, tail-stage suction branch pipes 123, a tail-stage suction main pipe 124, and a tail-stage suction fan 125; the tail-stage suction plate 120 has the same structure as the first-stage suction plate 100; the bottom of the tail-stage suction box 121 is connected to two tail-stage suction branch pipes 123, and the two tail-stage suction branch pipes 123 merge to form the tail-stage suction main pipe 124, and the tail-stage suction fan 125 is connected in series in the middle of the suction main pipe.

[0052] For details on the air blowing system 2, please refer to Figure 5 and Figure 6 The system includes: a horizontal blowing box housing 21, a blowing outlet 20, blowing branch pipes 22, a blowing main pipe 23, a blowing fan 24, a blowing anemometer 25, and a blowing inlet 26. The blowing outlet 20 is a flat, elongated opening, with its outlet direction parallel to the main airflow direction of the wind tunnel (first direction X). Two blowing branch pipes 22 are connected to the bottom of the horizontal blowing box housing 21, which converge to form the blowing main pipe 23. The blowing anemometer 25 is installed between the blowing inlet 26 and the blowing fan 24, and the blowing fan 24 is installed on the blowing main pipe 23. The blowing system 2 is installed between the secondary suction system and the tertiary suction system to supplement the high-speed target airflow to the edge of the airflow.

[0053] Operating Procedure: After the wind tunnel test is started, the main airflow is ejected from the outlet 4 and first flows through the primary suction system 10: the primary suction fan 104 starts and removes the initial boundary layer airflow near the ground through the primary suction plate 100. The removed boundary layer airflow passes through the primary suction pipe 103. The airflow continues to flow through the secondary suction system, where the intermediate suction fan 114 starts and removes the boundary layer regenerated by the main airflow. The removed boundary layer airflow flows through the intermediate suction branch pipe 113. The airflow flows through the blowing system 2: the blowing fan 24 starts and, after passing through the blowing branch pipe 22 and the blowing box shell 21, ejects a high-speed target airflow from the blowing outlet 20 along the first direction (X) to increase the near-ground airflow velocity. The airflow flows through the tertiary suction system: the intermediate suction fan 114 further removes the residual boundary layer. Finally, the airflow flows through the tail suction system 12: the tail suction fan 125 starts and removes the downstream residual boundary layer.

[0054] The boundary layer control device provided in this embodiment, through its innovative design of staged suction and intermediate air replenishment, achieves full-process control of the boundary layer within the wind tunnel. This provides a stable and uniform flow field for automotive wind tunnel testing, making the automotive aerodynamic testing environment as close as possible to the actual driving conditions of a vehicle, thus improving the accuracy and reliability of experimental data. Simultaneously, all suction plates at each stage utilize low-noise perforated plates, effectively avoiding eddy noise and ensuring a background noise level of ≤50dB(A) at a wind speed of 120km / h, allowing for wind noise testing without additional processing. Furthermore, the intermediate-stage suction system 11 and the tail-stage suction system 12 employ a dual-suction branch pipe design, resulting in more uniform suction compared to the traditional single-pipe design.

[0055] Example 2

[0056] In practical applications, based on Embodiment 1, the boundary layer control device provided in this embodiment further includes an air collection system 3, a return air device 5, and a control system 6, with the specific structural forms as follows:

[0057] The gas collection system 3 includes: a gas collection box 30, gas collection ports 31, a rotating unit 32, and a gas collection pipe 33. The gas collection box 30 is a cylindrical hollow cavity with five gas collection ports 31 at the top (matching the intermediate stage suction branch pipe). The bottom of the gas collection box 30 is connected to the rotating unit 32 (including a servo motor, reduction mechanism, etc.) via bearings. The bottom of the rotating unit 32 and the gas collection pipe 33 are connected by a rubber sealing ring to ensure no air leakage during rotation. The end of the gas collection pipe 33 away from the rotating unit 32 splits into two paths: one path connects to the air blowing inlet 26 to provide an air source for the air blowing system 2, and the other path connects to the bottom of the return air device 5 to allow excess airflow to return to the test section.

[0058] The boundary layer control device provided in this embodiment collects the boundary layer airflow extracted by the intermediate stage suction system 11 through the gas collection system 3. Part of the airflow is supplied to the blowing system 2 as a gas source, and the other part is returned to the test section through the return air device 5. This realizes the internal circulation of the airflow, reduces the dependence on the air outlet 4, reduces the energy consumption of the fan, and improves the energy efficiency of the entire wind tunnel system. At the same time, the multi-path diversion design of the gas collection box 30 realizes the rational distribution and reuse of the extracted boundary layer airflow, further improving the accuracy and uniformity of airflow control.

[0059] The control system 6 includes: a first control PLC 61, a second control PLC 62, and a central control computer 60; the first control PLC 61 is connected to the suction fan via a hardwire; the second control PLC 62 is connected to the suction fan, the blowing fan, and the servo motor of the rotating unit via a hardwire; both the first control PLC 61 and the second control PLC 62 communicate with the central control computer 60 via Ethernet.

[0060] Based on Example 1, the multi-stage suction system also includes an anemometer, as detailed in the following reference. Figure 2 , Figure 3 as well as Figure 4 The anemometer is connected to the suction branch pipes at each level to collect the velocity of the boundary layer airflow drawn away by the multi-stage suction system. The collected data is summarized to the control system 6, which then controls the suction fan, the blowing fan, and the rotating unit in a coordinated manner to adjust the air volume of each system in a timely manner.

[0061] The control system 6 realizes real-time monitoring and closed-loop control of the suction fan, the blowing fan and the rotating unit 32. The anemometer collects the suction airflow data of the multi-stage suction system 1 in real time and feeds it back to the central control computer 60. The system can automatically adjust the fan speed to maintain the dynamic balance of airflow and pressure in the wind tunnel and improve the stability and consistency of the test environment.

[0062] Operating Procedure: After the wind tunnel test is started, the main airflow is ejected from the outlet 4 and first flows through the primary suction system 10: the primary suction fan 104 starts, and the primary suction plate 100 draws away the initial boundary layer airflow near the ground. The airflow is then reinjected into the test section through the primary suction pipe 103 and the return air device 5. The primary anemometer 102 monitors the suction speed in real time, and the data is fed back to the central control computer 60. The airflow continues to flow through the secondary suction system: the control system 6 drives the intermediate suction fan 114 to start, drawing away the boundary layer of airflow regeneration. The airflow enters the gas collection box 30 through the intermediate suction branch pipe 113. The airflow then flows through the blowing system 2: the blowing fan 24 starts, obtains air from the gas collection box 30, and flows through the blowing branch pipe 22 and the outer shell of the blowing box 2. After 1, a high-speed target airflow is ejected from the blowing outlet 20 along the first direction (X) to replenish the momentum of the boundary layer airflow; the airflow flows through the three-stage suction system: the intermediate stage suction fan 114 starts to further remove the residual boundary layer, and the airflow also enters the gas collection box 30. After merging with the secondary suction airflow, part of it is supplied to the blowing system 2 through the gas collection box 30, and the other part is returned to the return air device 5; the airflow finally flows through the tail stage suction system 12: the tail stage suction fan 125 starts to remove the downstream residual boundary layer, and the airflow is returned to the return air device 5 through the suction main pipe 124; throughout the process, the central control computer 60 adjusts the speed of each fan in real time through the first control PLC 61 and the second control PLC 62 to maintain the balance of wind tunnel flow and pressure.

[0063] When crosswind tests are conducted in the wind tunnel, the rotating unit 32 can drive the turntable to rotate as needed, causing the secondary and tertiary suction systems to turn accordingly, ensuring that the suction direction of the secondary and tertiary suction systems always matches the direction of the main airflow. This makes the device suitable for complex conditions such as crosswind tests, expands the experimental capabilities of the wind tunnel, and improves the practicality and versatility of the device.

[0064] In summary, the boundary layer control device provided in this embodiment, based on the first embodiment, further improves the energy efficiency, adaptability, stability, and intelligence level of the boundary layer control system by introducing gas collection and recovery, intelligent control, and rotation devices. This enables the wind tunnel equipped with the boundary layer control device to be applicable to complex test conditions and has good practicality.

[0065] Secondly, embodiments of this application also provide an automotive wind tunnel, including any of the boundary layer control devices described in the embodiments of the first aspect. Specific descriptions of the automotive wind tunnel embodiments are omitted here. The structure and connections of the automotive wind tunnel are known to those skilled in the art and will not be described in detail here.

[0066] In this application, "multiple" refers to two or more.

[0067] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0068] The terms “first,” “second,” “third,” “fourth,” etc., in this application (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0069] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0070] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C may be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.

[0071] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A boundary layer control device for a wind tunnel, the wind tunnel comprising: An air outlet, the air outlet being used to spray a main airflow along a first direction (X) into the wind tunnel, characterized in that the boundary layer control device includes: a multi-stage suction system and an air blowing system; The multi-stage suction system is used to remove the boundary layer airflow located at the edge of the main airflow. The multi-stage suction system includes a first-stage suction system, at least two intermediate suction systems and a tail-stage suction system arranged sequentially along the first direction (X). The first-stage suction system is connected to the air outlet. The blowing system is disposed between two adjacent intermediate stage systems. The blowing system is used to provide a target airflow along the first direction (X) to the airflow edge. The velocity of the target airflow is greater than the velocity of the boundary layer airflow.

2. The boundary layer control device according to claim 1, characterized in that, The blowing system is provided with a flat blowing port, which is used to blow out the target airflow.

3. The boundary layer control device according to claim 1, characterized in that, The boundary layer control device further includes: an air collection system and a return air device; Both the first-stage suction system and the last-stage suction system are connected to the return air device, and the intermediate-stage suction system is connected to the gas collection system. The gas collection system is connected to the return air device, which includes a return air inlet connected to the wind tunnel. The return air device is used to collect the boundary layer airflow drawn away by the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system, and to spray the boundary layer airflow upstream of the wind tunnel through the return air inlet.

4. The boundary layer control device according to claim 3, characterized in that, The gas collection system includes: a gas collection box, a gas collection pipe, a rotating unit, and a turntable; The gas collection box has multiple gas collection ports, which are connected to the intermediate stage suction system. The bottom of the gas collection box is connected to the rotating unit, the bottom of the rotating unit is movably connected to the gas collection pipe, and the gas collection pipe is connected to the return air device. The turntable is a disc with a rectangular opening along the diameter direction, and the two intermediate suction systems are respectively installed at both ends of the rectangular opening along the first direction (X).

5. The boundary layer control device according to claim 4, characterized in that, The first-stage suction system and the last-stage suction system have a first arc surface at the end near the turntable. The first arc surface is at the same center as the turntable, and the radius of the first arc surface is greater than the radius of the turntable. The end of any intermediate-stage suction system furthest from the center of the turntable is a second arc surface, which is the same as the center of the turntable, and the radius of the second arc surface is the same as the radius of the turntable.

6. The boundary layer control device according to claim 4, characterized in that, The upper surfaces of the primary suction system, the intermediate suction system, and the tail suction system, as well as the upper surface of the turntable, are all located on the same plane.

7. The boundary layer control device according to claim 1, characterized in that, The first-stage suction system, the intermediate-stage suction system, and the last-stage suction system are all equipped with an anemometers, which are used to measure the velocity of the boundary layer airflow.

8. The boundary layer control device according to claim 1, characterized in that, The boundary layer control device further includes a control system, which is connected to the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system to achieve centralized control of the first-stage suction system, the intermediate-stage suction system, and the tail-stage suction system.

9. A wind tunnel for testing the aerodynamic performance of a vehicle during operation, characterized in that, The wind tunnel includes: the boundary layer control device according to any one of claims 1-8.

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