Wind tunnel adjustment sheet structure with boundary conversion capability

Abstract

The present application belongs to the field of wind tunnel structure design, and discloses a wind tunnel adjusting sheet structure with boundary conversion capability. The wind tunnel adjusting sheet structure comprises a test section, an adjusting sheet assembly, a connecting rod, a boundary conversion device, a side wall plate and a dynamic seal, and comprises a transonic second throat or a supersonic diffusion section composed of the adjusting sheet assembly symmetrically arranged above and below the test section and the two side wall plates symmetrically arranged left and right. The adjusting sheet assembly comprises three adjusting sheets connected in sequence and a constraint damping unit fixed to the leeward surface of each adjusting sheet. The middle adjusting sheet is connected with an external driving mechanism through the connecting rod installed on the leeward surface. The boundary conversion device converts the boundary state from a friction constraint boundary state to a free boundary state, and reduces the fluid-structure coupling vibration response of the adjusting sheet assembly caused by oblique shock waves and normal shock waves. The active, real-time and reversible switching of the boundary condition is realized, and the vibration suppression capability, operation safety, sealing life and flow field control precision of the adjusting sheet are improved, which has engineering practical value.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel structural design, specifically relating to a wind tunnel adjustment plate structure with boundary transformation capability. Background Technology

[0002] Wind tunnels are indispensable key ground-based testing equipment for aerodynamic research. As aerospace vehicles develop towards higher speeds and more complex aerodynamic configurations, higher demands are placed on the testing capabilities of transonic and supersonic wind tunnels. In transonic and supersonic wind tunnels, a three-section control plate assembly is typically used as the core airflow control device. In transonic wind tunnels, this three-section control plate assembly is usually called the transonic second throat, and in supersonic wind tunnels, it is usually called the supersonic diffusion section. By interlocking the three sections of the control plate assembly to change the throat area, effective control of Mach number, shock wave position, and noise can be achieved.

[0003] A three-section regulating plate assembly typically consists of a front regulating plate, a middle regulating plate, and a rear regulating plate, hinged sequentially and symmetrically arranged downstream of the test section. During high-speed operation, the three-section regulating plate assembly is subjected to extreme aerodynamic loads caused by shock waves, turbulence, and complex pressure fluctuations. This multi-degree-of-freedom, lightweight, thin-walled flexible three-section regulating plate assembly is highly susceptible to strong fluid-structure interaction vibrations with the airflow, resulting in broadband random vibrations and potential flutter. Engineering practice shows that fluid-structure interaction vibrations can lead to the following serious consequences: complex shock waves and turbulence cause severe vibrations in the regulating plate assembly; the lack of normal constraints in the free boundary state makes the bending and torsional modes of the regulating plate assembly more easily excited, increasing the amplitude; excessive fluid-structure interaction vibrations can cause abnormal collisions and wear between the free edge and the seal, accelerating seal failure, causing airflow leakage, and affecting the flow field quality; low-frequency swaying in the free boundary state reduces the overall positioning stiffness of the regulating plate assembly, thereby affecting the control accuracy of the throat area.

[0004] Traditional solutions tend to enhance structural stiffness or increase damping. These methods primarily improve the structure but do not alter the fundamental dynamic boundary condition of the free boundary state. If the free boundary state could be transformed into a controlled constrained boundary under specific conditions of high dynamic pressure and strong disturbance, the dynamic characteristics of the structure would be fundamentally altered, significantly suppressing vibration. Currently, there is an urgent need to develop a wind tunnel regulating plate structure with boundary transformation capabilities. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a wind tunnel adjustment plate structure with boundary transformation capability, so as to overcome the defects of the prior art.

[0006] The wind tunnel regulating plate structure with boundary conversion capability of the present invention includes a test section, regulating plate assembly, connecting rod, boundary conversion device, side wall plate, and dynamic seal. The regulating plate assembly is located downstream of the test section and includes two symmetrically distributed sets of regulating plate assemblies. Each set of regulating plate assemblies includes a front regulating plate, a middle regulating plate, and a rear regulating plate that are sequentially hinged along the direction of supersonic airflow. The side wall plate and the regulating plate assembly form a transonic second throat or supersonic diffusion section with a rectangular cross section. A dynamic seal is provided at the intersection of the regulating plate assembly and the side wall plate. The middle regulating plate is connected to an external drive mechanism through a connecting rod installed on its leeward side. At least one boundary conversion device is provided on the leeward side of each regulating plate of the regulating plate assembly. The boundary conversion device enables each regulating plate to have a frictional constraint boundary state with pressed contact with the side wall plate and a free boundary state without contact. According to the working conditions, when frictional constraint is required, the free boundary state is converted to a frictional constraint boundary state, and when movement is required, the frictional constraint boundary state is restored to a free boundary state. The frictional constraint boundary state of the boundary conversion device is used to reduce the vibration energy of the regulating plate assembly caused by oblique shock waves and normal shock waves.

[0007] Furthermore, the boundary conversion device includes a friction plate, a base, a moving rod, and a driver; the base is fixed on the adjusting plate assembly, and the driver is mounted on the base; the moving rod passes through the center of the base, one end of the moving rod is fixed to the friction plate, the friction plate faces the side wall plate, and the other end of the moving rod is connected to the driver; the driver drives the moving rod to extend, causing the friction plate to press against the side wall plate to form a frictional constraint boundary state, and locking the relative position of the corresponding free edge of the adjusting plate and the side wall plate in the normal and tangential directions by the frictional force of the friction plate; conversely, the driver drives the moving rod to retract, causing the friction plate to disengage from the side wall plate, restoring the free boundary state from the frictional constraint boundary state, and restoring the motion freedom of the free edge of the adjusting plate.

[0008] Furthermore, the actuator can be an electric actuator, a hydraulic cylinder, a piezoelectric ceramic actuator, or a shape memory alloy actuator.

[0009] Furthermore, the contact surface of the friction pad is a flat or arc-shaped surface, and the surface is covered with a friction-enhancing material layer or has weight-reducing holes.

[0010] Furthermore, the front adjustment plate, middle adjustment plate, and rear adjustment plate are provided with orthogonal grid reinforcing ribs on the leeward side of the base plate. The orthogonal grid reinforcing ribs include horizontal stiffeners and vertical stiffeners, both of which are rectangular metal plates; the boundary transition device is installed on the vertical stiffeners.

[0011] Furthermore, the wind tunnel adjustment plate structure also includes a control system, which is connected to each boundary conversion device. The control system synchronously controls the boundary conversion device to switch between friction-constrained boundary state and free boundary state according to the wind tunnel test conditions or vibration sensor signals.

[0012] Furthermore, the number of boundary conversion devices is several, arranged sequentially along the free edge direction of the front adjustment plate, the middle adjustment plate and the rear adjustment plate, with a gap between adjacent boundary conversion devices.

[0013] The wind tunnel regulating plate structure with boundary transition capability of the present invention has the following characteristics: 1. Active vibration suppression: By actively converting the free boundary state into the friction-constrained boundary state, the overall stiffness of each adjustment plate is greatly increased, which has a significant effect on suppressing low-order bending modes and fundamentally weakens the root cause of fluid-structure interaction vibration. 2. Intelligent adaptation to operating conditions; capable of intelligently controlling the operation of the boundary switching device based on the wind tunnel operating Mach number, dynamic pressure, or monitored vibration signals; switching to the friction-constrained boundary state to maintain stability under high load and vibration-prone conditions; and restoring the free boundary state to maintain smoothness when the adjustment plate needs to move. 3. Improve seal life; By using friction-constrained boundary conditions, the large-scale vibration of the free edges of each adjusting plate is suppressed, which greatly reduces the impact and wear of the free edges of each adjusting plate on the dynamic seal, effectively extending the service life of the dynamic seal; 4. High control precision; the friction constraint boundary state provides additional positioning support, reduces the deformation and shaking of each adjustment plate under the action of airflow, can improve the control precision of the geometry of the transonic second throat and the supersonic diffuser throat, and can continuously maintain the geometry of the transonic second throat and the supersonic diffuser throat. 5. Safety redundancy and reliability; adopts electromechanical actuation, with reliable structure; even in the event of power failure, it can maintain the frictional constraint boundary state and free boundary state by default, without affecting wind tunnel safety.

[0014] The wind tunnel regulating plate structure of the present invention with boundary transformation capability solves the problems of excessive fluid-structure interaction vibration, easy seal damage and insufficient control accuracy caused by high-speed airflow. It can actively transform the friction-constrained boundary state and the free boundary state according to the working conditions, realize the active, real-time and reversible switching of boundary conditions, and can make intelligent adjustments according to the working conditions. It significantly improves the vibration suppression capability, operational safety, seal life and flow field control accuracy of the regulating plate, and has practical engineering value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the wind tunnel regulating plate structure with boundary transformation capability according to the present invention; Figure 2 for Figure 1 AA cross-section view; Figure 3 This is a schematic diagram of the free boundary state of the wind tunnel adjustment plate structure with boundary transformation capability of the present invention; Figure 4 This is a schematic diagram of the frictional constraint boundary state of the wind tunnel adjustment plate structure with boundary transformation capability of the present invention; Figure 5 for Figure 1 This is a schematic diagram of the wind tunnel regulating plate structure with boundary transformation capability according to the present invention.

[0016] In the diagram, 1. Test section; 2. Adjustment plate assembly; 3. Connecting rod; 4. Boundary transition device; 5. Side wall plate; 6. Dynamic seal; 21. Front adjustment plate; 22. Middle adjustment plate; 23. Rear adjustment plate; 221. Transverse rib plate; 222. Bottom plate; 223. Longitudinal rib plate; 41. Friction plate; 42. Base; 43. Moving rod; 44. Driver. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] like Figure 1 , Figure 2 As shown, the wind tunnel regulating plate structure with boundary transition capability of the present invention includes a test section 1, regulating plate assembly 2, connecting rod 3, boundary transition device 4, side wall plate 5, and dynamic seal 6. The regulating plate assembly 2 is located downstream of the test section 1 and includes two symmetrically distributed sets of regulating plate assemblies 2. Each set of regulating plate assemblies 2 includes a front regulating plate 21, a middle regulating plate 22, and a rear regulating plate 23 that are sequentially hinged along the direction of supersonic airflow. The side wall plate 5 and the regulating plate assembly 2 form a transonic second throat or supersonic diffusion section with a rectangular cross section. A dynamic seal 6 is provided at the intersection of the regulating plate assembly 2 and the side wall plate 5. The middle regulating plate 22 is installed by... The connecting rod 3 on its leeward side is connected to the external drive mechanism; at least one boundary conversion device 4 is provided on the leeward side of each adjustment plate of the adjustment plate assembly 2. The boundary conversion device 4 enables each adjustment plate to have a frictional constraint boundary state with pressing contact with the side wall plate 5 and a free boundary state without contact. According to the working conditions, when frictional constraint is required, the free boundary state is converted to the frictional constraint boundary state, and when movement is required, the frictional constraint boundary state is restored to the free boundary state. The frictional constraint boundary state of the boundary conversion device 4 is used to reduce the vibration energy of the adjustment plate assembly 2 caused by oblique shock waves and normal shock waves.

[0019] Furthermore, such as Figure 3 , Figure 4As shown, the boundary conversion device 4 includes a friction plate 41, a base 42, a moving rod 43, and a driver 44. The base 42 is fixed on the adjusting plate assembly 2, and the driver 44 is mounted on the base 42. The moving rod 43 passes through the center of the base 42. One end of the moving rod 43 is fixed to the friction plate 41, which faces the side wall plate 5. The other end of the moving rod 43 is connected to the driver 44. The driver 44 drives the moving rod 43 to extend, causing the friction plate 41 to press against the side wall plate 5 to form a friction constraint boundary state. The friction force of the friction plate 41 locks the relative position of the corresponding free edge of the adjusting plate and the side wall plate 5 in the normal and tangential directions. Conversely, the driver 44 drives the moving rod 43 to retract, causing the friction plate 41 to disengage from the side wall plate 5, restoring the free boundary state from the friction constraint boundary state, and restoring the motion freedom of the free edge of the adjusting plate.

[0020] Furthermore, the actuator 44 is an electric actuator, a hydraulic cylinder, a piezoelectric ceramic actuator, or a shape memory alloy actuator.

[0021] Furthermore, the contact surface of the friction plate 41 is a flat or arc-shaped surface, and the surface is covered with a friction-enhancing material layer or has weight-reducing holes.

[0022] Furthermore, such as Figure 5 As shown, the front adjustment plate 21, the middle adjustment plate 22 and the rear adjustment plate 23 are provided with orthogonal grid reinforcing ribs on the leeward side of the base plate 222. The orthogonal grid reinforcing ribs include horizontal stiffeners 221 and vertical stiffeners 223. Both horizontal stiffeners 221 and vertical stiffeners 223 are rectangular metal plates. The boundary conversion device 6 is installed on the vertical stiffeners 223.

[0023] Furthermore, such as Figure 5 As shown, the wind tunnel adjustment plate structure also includes a control system. The control system is connected to each boundary conversion device 4. The control system synchronously controls the boundary conversion device 4 to switch between friction-constrained boundary state and free boundary state according to the wind tunnel test conditions or vibration sensor signals.

[0024] Furthermore, such as Figure 5 As shown, there are several boundary conversion devices 4, which are arranged sequentially along the free edge direction of the front adjustment plate 21, the middle adjustment plate 22 and the rear adjustment plate 23, and there is a gap between adjacent boundary conversion devices 4.

[0025] Example 1: In this example, the actuator 44 is an explosion-proof miniature electric actuator, the moving rod 43 is a high-strength alloy rod; the surface of the friction plate 41 is covered with rectangular fluororubber; the vibration sensor is an accelerometer. During normal operation, the adjusting plate assembly 2 remains stationary or undergoes minor adjustments; the moving rod 43 retracts, and the friction plate 41 maintains a gap of approximately 2-3 mm with the stainless steel sidewall plate 5 of the wind tunnel, with the boundary conversion device 4 in a free boundary state; when the wind tunnel enters a high dynamic pressure test state (dynamic pressure greater than 50 kPa) or the acceleration sensor detects excessive vibration (effective value of first-order bending mode acceleration greater than 5g), the control system issues a command, and the moving rod 43 of each boundary conversion device 4 extends, pressing the friction plate 41 tightly onto the sidewall plate 5 with a predetermined pressure of 5000 N, forming a friction constraint, and is in a friction constraint boundary state; after the test, the moving rod 43 retracts, restoring the free boundary state for the next adjustment.

[0026] Example 2: Based on Example 1, this example designs the surface of the friction plate 41 as an arc-shaped surface that matches the curvature of the wind tunnel wall panel to increase the contact area; the actuator 44 adopts a piezoelectric ceramic actuator, which has a faster response speed. According to real-time vibration spectrum analysis, at the moment when a specific dangerous frequency component appears, the control system immediately enters the friction constraint boundary state to realize active locking control based on vibration frequency.

[0027] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, all features disclosed in the present invention, or all steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A wind tunnel regulating plate structure with boundary transition capability, characterized in that, The wind tunnel regulating plate structure includes a test section (1), regulating plate assembly (2), connecting rod (3), boundary transition device (4), side wall plate (5), and dynamic seal (6); the regulating plate assembly (2) is located downstream of the test section (1) and includes two symmetrically distributed regulating plate assemblies (2). Each regulating plate assembly (2) includes a front regulating plate (21), a middle regulating plate (22), and a rear regulating plate (23) that are sequentially hinged along the direction of supersonic airflow. The side wall plate (5) and the regulating plate assembly (2) form a transonic second throat or supersonic diffusion section with a rectangular cross section. A dynamic seal (6) is provided at the intersection of the regulating plate assembly (2) and the side wall plate (5); the middle regulating plate (22) The adjustment plate assembly (2) is connected to an external drive mechanism via a connecting rod (3) installed on its leeward side; each adjustment plate of the adjustment plate assembly (2) is provided with at least one boundary conversion device (4) on its leeward side. The boundary conversion device (4) enables each adjustment plate to have a frictional constraint boundary state with a pressing contact with the side wall plate (5) and a free boundary state without contact. According to the working conditions, when frictional constraint is required, the free boundary state is converted to a frictional constraint boundary state, and when movement is required, the frictional constraint boundary state is restored to a free boundary state. The frictional constraint boundary state of the boundary conversion device (4) is used to reduce the vibration energy of the adjustment plate assembly (2) caused by oblique shock waves and normal shock waves.

2. The wind tunnel regulating plate structure with boundary transition capability according to claim 1, characterized in that, The boundary conversion device (4) includes a friction plate (41), a base (42), a moving rod (43), and a driver (44). The base (42) is fixed on the adjusting plate assembly (2), and the driver (44) is installed on the base (42). The moving rod (43) passes through the center of the base (42). One end of the moving rod (43) is fixed to the friction plate (41), which faces the side wall plate (5). The other end of the moving rod (43) is connected to the driver (44). The driver (44) drives the moving rod (43) to extend, causing the friction plate (41) to press against the side wall plate (5) to form a friction constraint boundary state. The friction force of the friction plate (41) locks the relative position of the free edge of the corresponding adjusting plate and the side wall plate (5) in the normal and tangential directions. Conversely, the driver (44) drives the moving rod (43) to retract, causing the friction plate (41) to disengage from the side wall plate (5), restoring the free boundary state from the friction constraint boundary state, and restoring the motion freedom of the free edge of the adjusting plate.

3. The wind tunnel regulating plate structure with boundary transition capability according to claim 2, characterized in that, The actuator (44) is an electric actuator, a hydraulic cylinder, a piezoelectric ceramic actuator, or a shape memory alloy actuator.

4. The wind tunnel regulating plate structure with boundary transition capability according to claim 2, characterized in that, The contact surface of the friction plate (41) is a plane or an arc surface, and the surface is covered with a friction-enhancing material layer or has weight-reducing holes.

5. The wind tunnel regulating plate structure with boundary transition capability according to claim 1, characterized in that, The front adjustment plate (21), the middle adjustment plate (22) and the rear adjustment plate (23) are provided with orthogonal grid reinforcing ribs on the leeward side of the base plate (222). The orthogonal grid reinforcing ribs include horizontal stiffeners (221) and vertical stiffeners (223). Both horizontal stiffeners (221) and vertical stiffeners (223) are rectangular metal plates. The boundary conversion device (6) is installed on the vertical stiffeners (223).

6. The wind tunnel regulating plate structure with boundary transition capability according to claim 1, characterized in that, The wind tunnel adjustment plate structure also includes a control system, which is connected to each boundary conversion device (4). The control system synchronously controls the boundary conversion device (4) to switch between the friction-constrained boundary state and the free boundary state according to the wind tunnel test conditions or vibration sensor signals.

7. The wind tunnel regulating plate structure with boundary transition capability according to claim 1, characterized in that, The number of boundary conversion devices (4) is several, arranged sequentially along the free edge direction of the front adjustment plate (21), the middle adjustment plate (22) and the rear adjustment plate (23), with a gap between adjacent boundary conversion devices (4).

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