A boundary layer simulation device and experimental setup based on variable-height turbulence column-induced boundary layer.

Abstract

This invention discloses a boundary layer simulation device and experimental setup based on variable-height turbulence columns. The boundary layer simulation device includes a frame, a connecting plate, a slide rail, a slider, and a lead screw. The turbulence columns are fixed to the connecting plate and extend from the upper and lower support plates. The connecting plate is threadedly connected to the lead screw. A motor at the bottom drives a pulley to rotate, which in turn drives the lead screw, thus changing the height of the connecting plate and the turbulence columns it fixes. This invention induces boundary layers of different heights by actively controlling the height of the turbulence columns. Furthermore, by controlling the number, arrangement, and height of the turbulence columns, it can simulate boundary layers of different thicknesses and velocity profiles.

Description

Technical Field

[0001] This invention relates to the field of fluid mechanics experiments, and more particularly to a boundary layer simulation device based on variable-height turbulence column-induced flow. Background Technology

[0002] A boundary layer is a fluid flow region near the surface of an object, characterized by reduced flow velocity and increased flow complexity. On the surface of an aircraft, the presence of a boundary layer leads to increased drag, decreased aerodynamic performance, and even turbulence. Therefore, controlling the boundary layer flow and reducing its thickness is a crucial means of improving aircraft performance. Currently, common boundary layer control methods include passive and active control. Passive control involves influencing boundary layer flow by altering the aircraft's surface structure, such as airfoil design and surface texture; active control involves applying external control forces within the boundary layer, such as airflow purging or aerodynamic surface excitation, to change the flow state. Traditional boundary layer simulation devices often employ aerodynamic surface excitation, using aerodynamic surface exciters placed on the aircraft surface to generate aerodynamic effects and control the boundary layer flow.

[0003] However, traditional boundary layer simulation devices have some problems. First, the size and shape of aerodynamic surface actuators are usually fixed and cannot be flexibly adjusted; second, aerodynamic surface actuators can only produce fixed aerodynamic effects and cannot be adjusted according to the actual operating conditions of the aircraft; finally, the control effect of aerodynamic surface actuators is greatly affected by external environmental interference and has poor stability. Summary of the Invention

[0004] Purpose of the Invention: This invention addresses the problems of traditional boundary layer simulation devices, such as insufficient control flexibility and adjustability, poor adaptability and control performance, and significant susceptibility to external interference. It aims to provide a boundary layer simulation device based on variable-height turbulence-induced cylinders. Utilizing variable-height cylindrical inducers as control elements, the flow state of the boundary layer is altered by adjusting the height and arrangement of the cylinders, thus satisfying the simulation requirements for boundary layers of different thicknesses and velocity profiles.

[0005] Technical Solution: To solve the above problems, this invention employs a boundary layer simulation device based on variable-height turbulence-induced columns, comprising a frame, a slide rail assembly located on the inner sidewalls of both sides of the frame, and a minor turbulence-induced column assembly located within the frame; each turbulence-induced column assembly includes a connecting plate and a minor turbulence-induced column extending vertically through the connecting plate; the slide rail assembly is provided with several parallel slide rails extending vertically; sliders are provided at both ends of the connecting plate to cooperate with the slide rails at corresponding positions; the minor turbulence-induced columns on each turbulence-induced column assembly are arranged in a row, and the turbulence-induced columns respectively provided on the minor turbulence-induced column assembly are arranged in several rows from front to back; in each row of turbulence-induced columns, the arrangement interval length between adjacent turbulence-induced columns is the same, and is different from the arrangement interval length of other rows of turbulence-induced columns; it also includes several actuators, each actuator independently driving the connecting plate of a turbulence-induced column assembly, causing the turbulence-induced columns on the connecting plate to move vertically along the slide rails.

[0006] Furthermore, the driver includes a lead screw located within the frame and a drive motor for driving the lead screw; the lead screw is located between two slide rails and extends parallel to the slide rails, the lead screw passes through the connection and is threadedly connected to the connecting plate, and when the lead screw rotates, it drives the connecting plate to move up or down along the slide rails.

[0007] Furthermore, each spoiler column assembly includes several connecting plates arranged vertically along the same slide rail, and each connecting plate is fixed with an independent spoiler column; the upper connecting plate is provided with a through hole, and the spoiler column fixed on the lower connecting plate passes upward through the upper connecting plate and is clearance-fitted with the through hole on the upper connecting plate.

[0008] Furthermore, each of the several connecting plates in each spoiler column assembly is provided with an independent driver; and the lead screws of the several drivers corresponding to the spoiler column assembly are arranged parallel to each other and pass through each connecting plate in the spoiler column assembly, with one driver only threadedly engaging with one connecting plate and clearance engaging with the other connecting plates.

[0009] Furthermore, each driver includes a drive motor, two pulleys, and a belt; the bottom of the frame is provided with mounting platforms extending to both sides, and several drive motors are mounted on the upper surface of the mounting platforms on both sides. Each lead screw in the frame passes through the bottom of the frame and is coaxially connected to a pulley, and the other pulley is coaxially connected to the drive shaft of the drive motor. The two pulleys are connected and driven by a belt.

[0010] Furthermore, the top of the frame is provided with an opening for the turbulence column to pass through, the turbulence column passing through the top of the frame and extending upward.

[0011] Furthermore, all the turbulence-causing columns are cylindrical turbulence-causing columns with the same cross-sectional diameter.

[0012] Furthermore, each connecting plate has a lead screw nut installed on its top or bottom, which mates with the lead screw that drives the connecting plate, and there is only one lead screw nut on each connecting plate.

[0013] Furthermore, three spoiler column assemblies are provided. The spoiler columns in the first spoiler column assembly are arranged at adjacent 90mm intervals; the spoiler columns in the second spoiler column assembly are arranged at adjacent 70mm intervals; and the spoiler columns in the third spoiler column assembly are arranged at adjacent 50mm intervals.

[0014] Beneficial Effects: Compared to existing devices, the significant advantage of this invention is that it adjusts the flow state of the airflow boundary layer through the turbulence column region by changing the height of each row of turbulence columns and / or the height of some turbulence columns in the same row, thereby achieving the simulation of boundary layers with different thicknesses and velocity profiles. Compared with traditional aerodynamic surface exciters, the variable height cylindrical inducer has the following advantages:

[0015] The height of each row and / or each individual baffle column in the same row can be adjusted according to actual needs, providing greater flexibility and adjustability; the baffle columns have better adaptability and control performance; the control effect of the baffle columns is less affected by external environmental interference and has better stability, which can meet the boundary layer simulation of different thicknesses and different velocity profiles.

[0016] The present invention also provides an experimental apparatus having the above-mentioned variable height turbulence column-induced boundary layer simulation device. The variable height turbulence column-induced boundary layer simulation device is installed in front of the experimental apparatus, and the frame is installed inside the experimental apparatus. Only the turbulence column portion that penetrates through the top of the frame and extends upward is directly facing the airflow. A test component is installed at the rear of the experimental apparatus. The airflow passes through the turbulence column and reaches the test component. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the boundary layer simulation device induced by variable height turbulence columns in Example 1;

[0018] Figure 2 for Figure 1 A schematic diagram of a boundary layer simulation device based on variable height turbulence column inverted 180° with the bottom facing upwards;

[0019] Figure 3 This is a schematic diagram of the frame structure in Example 1;

[0020] Figure 4 This is a schematic diagram showing the connection between the connecting plate, the slide rail slider, and the lead screw in Embodiment 1;

[0021] Figure 5 This is a schematic diagram of the motor belt pulley transmission structure in Example 1;

[0022] Figure 6 This is a schematic diagram of the distribution of turbulence columns in Example 1;

[0023] Figure 7 This is a schematic diagram of the experimental apparatus in Example 2;

[0024] Figure 8 This is a schematic diagram showing the height of each row of turbulence columns in the boundary layer simulation device used in Example 2;

[0025] Figure 9 To adopt Figure 8 A schematic diagram showing the change in boundary layer height at the measurement location after adjusting the height of each row of turbulence columns. Detailed Implementation

[0026] Example 1

[0027] like Figures 1 to 4 As shown, a boundary layer simulation device based on variable height turbulence column-induced flow in this embodiment includes a frame 1, a slide rail assembly located on the inner sidewalls of both sides of the frame 1, and a turbulence column assembly located within the frame 1.

[0028] Combination Figure 4 As shown, each spoiler column assembly includes a connecting plate 3 and a minor spoiler column 2 extending vertically through the connecting plate 3. The slide rail assembly has several parallel slide rails 8 extending vertically; both ends of the connecting plate 3 have sliders 9 that mate with the corresponding slide rails 8. The minor spoiler columns 2 on each spoiler column assembly are arranged in a row, and the spoiler columns 2 on each assembly are arranged in several rows from front to back; in each row of spoiler columns 2, the spacing between adjacent spoiler columns is the same, but different from the spacing between spoiler columns in other rows. For example, combined with... Figure 6 As shown, in this embodiment, three spoiler column assemblies are provided. The spoiler columns in the first spoiler column assembly are arranged at adjacent 90mm intervals; the spoiler columns in the second spoiler column assembly are arranged at adjacent 70mm intervals; and the spoiler columns in the third spoiler column assembly are arranged at adjacent 50mm intervals. Of course, in other embodiments, two or more than three spoiler column assemblies may be provided, or the spacing may be adjusted as needed, which will not be elaborated here. Furthermore, in this embodiment, all spoiler columns 2 are cylindrical spoiler columns with the same cross-sectional diameter.

[0029] In this embodiment, the function of adjusting the height of each spoiler column in the same row of the same spoiler column assembly to different heights is further added. For example... Figure 1As shown, each spoiler column assembly includes several connecting plates 3 arranged vertically along the same slide rail (in this embodiment, two connecting plates 3 are arranged vertically). Each connecting plate has an independent spoiler column 2 fixed to it; the upper connecting plate 3 has a through hole, and the spoiler column 2 fixed to the lower connecting plate 3 passes upward through the upper connecting plate with a clearance fit to the through hole in the upper connecting plate. That is, the lower connecting plate 3 can independently drive the spoiler column 2 fixed thereon to move up and down without interfering with the spoiler column on the upper connecting plate, thereby enabling independent adjustment of the height of each spoiler column in the same row within the same spoiler column assembly.

[0030] Combination Figure 1 , Figure 2 and Figure 5 As shown, in this embodiment, a combination of a lead screw 4, a drive motor 5, two pulleys 7, and a belt 6 is used as a driver to drive the connecting plate 3 to move along the slide rail 8. The bottom of the frame 1 is provided with mounting platforms extending to both sides. Several drive motors 5 are mounted on the upper surface of the mounting platforms on both sides. Each lead screw 4 within the frame 1 passes through the bottom of the frame 1 and is coaxially connected to a pulley 7. The other pulley 7 is coaxially connected to the drive shaft of the drive motor 5. The two pulleys 7 are connected and driven by the belt 6.

[0031] As mentioned earlier, each spoiler column assembly includes several connecting plates 3 arranged vertically along the same slide rail. Therefore, each actuator independently drives one connecting plate 3 of the spoiler column assembly, causing the spoiler column 2 on that connecting plate 3 to move vertically along the slide rail. Specifically, each of the several connecting plates 3 in each spoiler column assembly is provided with an independent actuator; and the lead screws of the several actuators corresponding to the spoiler column assembly are arranged parallel to each other and all pass through each connecting plate 3 in the spoiler column assembly. One actuator is threadedly engaged with only one connecting plate and has clearance engagement with the other connecting plates. The threaded connection between the lead screw 4 and the connecting plate 3 is achieved through a lead screw nut. Each connecting plate 3 has a lead screw nut 10 installed on its top or bottom that engages with the lead screw driving the connecting plate. There is only one lead screw nut on each connecting plate 3.

[0032] The aforementioned simulation device can simulate boundary layers of varying thicknesses and velocity profiles. Its principle is as follows: the flow-inducing columns affect the boundary layer thickness primarily due to changes in the velocity profile as the fluid flows around them. At the front surface of the flow-inducing columns, the fluid velocity is slower, resulting in greater drag and a thicker boundary layer. Conversely, at the rear surface, the fluid velocity is higher, and the influence of the flow-inducing columns is less, leading to a gradually thinner boundary layer. In practical applications, the shape, number, size, and distribution of the cylindrical flow-inducing columns can be varied according to specific experimental requirements to achieve different objectives. Furthermore, increasing the number of motors can enable different control methods. The specific implementation method depends on the actual situation.

[0033] Example 2

[0034] like Figure 7 As shown, the present invention also provides an experimental apparatus 14 with the variable-height spoiler-induced boundary layer simulation device described in Embodiment 1 above. The variable-height spoiler-induced boundary layer simulation device 12 is installed in front of the experimental apparatus, and the frame is installed inside the experimental apparatus. Only the spoiler column portion, which extends upward through the top of the frame, faces the incoming airflow. A test component 13 (e.g., an air intake, an aircraft fuselage wing) is installed at the rear of the experimental apparatus. The airflow passes through the spoiler column and reaches the test component to test and study the aerodynamic performance characteristics of the boundary layer at different heights. For example: Figure 8 As shown, the device in Example 1 was tested with the height of the first row of spoiler columns adjusted to 70mm, the second row to 35mm, and the third row to 0mm. Changing the airflow velocity in the incoming direction yields the following change in boundary layer height at the measurement location behind the device: Figure 9 As shown.

Claims

1. A boundary layer simulation device based on variable-height turbulence column-induced boundary layer, characterized in that, The system includes a frame (1), a slide rail assembly located on the inner sidewalls of both sides of the frame, and a minor disturbance column assembly located within the frame. Each disturbance column assembly includes a connecting plate (3) and a minor disturbance column (2) extending vertically through the connecting plate (3). The slide rail assembly is provided with several parallel slide rails (8) extending vertically. The two ends of the connecting plate (3) are provided with sliders (9) that cooperate with the corresponding slide rails (8). The minor disturbance columns (2) on each disturbance column assembly are arranged in a row, and the disturbance columns (2) respectively provided on the minor disturbance column assembly are arranged in several rows from front to back. In each row of disturbance columns (2), the arrangement interval length between two adjacent disturbance columns is the same, and the arrangement interval length is different from that of other rows of disturbance columns (2). It also includes several drivers, each of which independently drives a connecting plate (3) of a spoiler column assembly, causing the spoiler column (2) on the connecting plate (3) to move up and down along the slide rail.

2. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 1, characterized in that, The driver includes a lead screw (4) located within the frame and a drive motor (5) for driving the lead screw; the lead screw is located between the two slide rails and extends parallel to the slide rails, the lead screw passes through the connecting plate (3) and is internally threaded to the connecting plate (3), and when the lead screw rotates, it drives the connecting plate to move up or down along the slide rails.

3. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 2, characterized in that, Each spoiler column assembly includes several connecting plates (3) arranged vertically along the same slide rail, and each connecting plate is fixed with an independent spoiler column (2); the upper connecting plate is provided with a through hole, and the spoiler column fixed on the lower connecting plate passes through the upper connecting plate upward and is clearance-fitted with the through hole on the upper connecting plate.

4. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 3, characterized in that, Each of the several connecting plates (3) in each spoiler column assembly is provided with an independent driver; and the lead screws of the several drivers corresponding to the spoiler column assembly are arranged in parallel to each other and pass through each connecting plate (3) in the spoiler column assembly. One of the drivers is threadedly engaged with only one connecting plate and has clearance engagement with the other connecting plates.

5. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 4, characterized in that, Each driver includes a drive motor, two pulleys and a belt; the bottom of the frame is provided with mounting platforms extending to both sides, and several drive motors are mounted on the upper surface of the mounting platforms on both sides. Each lead screw in the frame passes through the bottom of the frame and is coaxially connected to a pulley, and the other pulley is coaxially connected to the drive shaft of the drive motor. The two pulleys are connected and driven by a belt.

6. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 1, characterized in that, The top of the frame has an opening through which the turbulence column (2) passes, and the turbulence column (2) extends upward through the top of the frame.

7. The boundary layer simulation device induced by a variable-height turbulence column as described in any one of claims 1 to 6, characterized in that, All the turbulence columns (2) are cylindrical turbulence columns with the same cross-sectional diameter.

8. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 4, characterized in that, Each connecting plate (3) has a lead screw nut (10) installed on its top or bottom, which cooperates with the lead screw that drives the connecting plate. There is only one lead screw nut on each connecting plate (3).

9. The boundary layer simulation device induced by a variable-height turbulence column as described in claim 8, characterized in that, The system is equipped with three spoiler columns. The spoiler columns in the first spoiler column assembly are arranged at 90mm intervals; the spoiler columns in the second spoiler column assembly are arranged at 70mm intervals; and the spoiler columns in the third spoiler column assembly are arranged at 50mm intervals.

10. An experimental apparatus having a boundary layer simulation device induced by a variable-height turbulence column as described in any one of claims 1 to 9, characterized in that, The boundary layer simulation device induced by the variable height turbulence column is installed in front of the experimental device, and the frame is installed inside the experimental device. Only the part of the turbulence column that runs through the top of the frame and extends upward is facing the airflow. The test component is installed at the rear of the experimental device. The airflow passes through the turbulence column and reaches the test component.

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