A continuous wind tunnel flutter test model protection device and method

Abstract

A protective device and method for a continuous wind tunnel flutter test model, belonging to the field of wind tunnel testing technology, addresses the problem that traditional physical methods cannot measure the deformation of special structural models during flutter tests. The device includes a reflector and a laser displacement meter matrix, which are respectively positioned opposite each other on the two sidewalls of the wind tunnel test section. One end of the test model is connected to one sidewall, and the free end of the test model extends horizontally towards the other sidewall. The amplitude at a specified position on the test model is calculated using the laser displacement meter matrix, and this is used as the criterion for the activation of the safety protection device. Once the calculated result exceeds the safe range, the safety protection device can be quickly activated to protect the test model and stop the wind tunnel test. This device and method overcome the shortcomings of using other types of sensors for safety threshold judgment in continuous transonic wind tunnel flutter tests, avoiding damage to the wind tunnel and test model during flutter tests.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology, and particularly relates to a protective device and method for a continuous wind tunnel flutter test model. Background Technology

[0002] Flutter testing is a common type of test in continuous wind tunnels. When an aircraft flies in the transonic range, its aerodynamic characteristics exhibit strong nonlinear features due to shock wave motion, flow separation and other phenomena. Flutter testing is used to detect the flutter boundary of the aircraft. Once the test model exhibits flutter, the entire wind tunnel test system needs to be effectively protected to prevent damage to the test model or the wind tunnel itself during the flutter process.

[0003] Generally, flutter testing focuses on the flutter characteristics of the test model, using accelerometers or strain sensors to acquire flutter data and determine safety protection actions. However, for test models with special structures, such as wings with significant wingtip deformation, or models with limited sensor placement, the deformation at a specific location can also be used as a basis for flutter safety protection. Due to space constraints within the wind tunnel, measuring the deformation of the test model using traditional physical methods is often impractical. Therefore, establishing an effective continuous wind tunnel flutter test model protection device and method to improve the reliability and safety of aircraft flutter testing is particularly necessary. Summary of the Invention

[0004] The purpose of this invention is to provide a protective device and method for a continuous wind tunnel flutter test model, to solve the problem that traditional physical methods cannot measure the deformation of special structural models during flutter tests. The technical solution adopted by this invention is as follows:

[0005] A protective device for a continuous wind tunnel flutter test model includes a reflector, a laser displacement meter matrix, and a safety protection device. The two side walls of the wind tunnel test section are defined as the first side wall and the second side wall, respectively. The reflector and the laser displacement meter matrix are respectively arranged opposite to each other on the inner walls of the first side wall and the second side wall. The fixed end of the test model is connected to the first side wall, and the free end of the test model extends horizontally towards the second side wall. A trapezoidal groove is provided at the end of the test model facing the first side wall, and a notch adapted to the trapezoidal groove is provided on the first side wall.

[0006] The safety protection device includes a stabilizing bracket, a roller assembly, a stabilizing head, a hydraulic cylinder, and a hydraulic system. Two stabilizing brackets, one above the other, are fixed to the outer side of the first side wall. The stabilizing brackets are equipped with roller assemblies. The stabilizing head is connected to the piston rod of the hydraulic cylinder. The upper and lower ends of the stabilizing head are respectively in rolling engagement with the two sets of roller assemblies. The hydraulic system drives the piston rod of the hydraulic cylinder to extend and retract. When the piston rod of the hydraulic cylinder extends, the stabilizing head passes through the first side wall and abuts against the bottom of the trapezoidal groove.

[0007] Furthermore, the hydraulic system includes a directional valve and a hydraulic pump. The directional valve is a three-position four-way solenoid directional valve. The oil chambers on both sides of the hydraulic cylinder are respectively connected to the A port and B port of the directional valve. The P port of the directional valve is connected to the oil tank through the hydraulic pump, and the T port of the directional valve is connected to the oil tank.

[0008] Furthermore, the hydraulic system also includes an accumulator, and the P port of the directional valve is connected to the accumulator.

[0009] Furthermore, the laser displacement meter matrix includes three rows of laser displacement meter groups. Each row of the laser displacement meter group includes several horizontally spaced laser displacement meters. In order from top to bottom, the vertical distance h1 between the first row of laser displacement meter groups and the test model is 100% of the maximum positive amplitude H of the free end of the test model; the vertical distance h2 between the second row of laser displacement meter groups and the test model is 90% of the maximum positive amplitude H of the free end of the test model; and the vertical distance h3 between the third row of laser displacement meter groups and the test model is 80% of the maximum positive amplitude H of the free end of the test model.

[0010] Furthermore, each laser displacement gauge is connected to the flutter measurement and control system via a signal cable, and the flutter measurement and control system is electrically connected to the alarm indicator light, manual emergency stop switch, reversing valve and hydraulic pump respectively. The wind tunnel measurement and control system is connected to the flutter measurement and control system via a network cable.

[0011] This invention also provides a method for protecting a continuous wind tunnel flutter test model, which is based on the aforementioned protective device for a continuous wind tunnel flutter test model, and includes the following steps:

[0012] Step 1: Start the experiment. Each laser displacement meter in the laser displacement meter matrix emits a laser beam, and the data of the laser displacement meter matrix receiving the laser beam reflected by the reflector is monitored.

[0013] Step 2: When the laser displacement meter group in the third row receives a discontinuous laser beam signal reflected by the reflector, the flutter control system will trigger the alarm indicator light as a reminder.

[0014] When the laser displacement meter group in the second row receives a discontinuous laser beam signal reflected by the reflector, the manual emergency stop switch is activated, and the flutter control system is in the state of receiving emergency stop signals. The operator can decide whether to open or close the manual emergency stop switch to perform an emergency stop operation.

[0015] When the laser displacement gauge group in the first row receives a discontinuous laser beam signal reflected by the reflector, the flutter control system activates the safety protection device and sends a stop test command to the wind tunnel control system.

[0016] Step 3: End the experiment and stop monitoring the data of the laser displacement meter matrix.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention proposes a continuous wind tunnel flutter test model protection device based on a laser displacement meter matrix. The device consists of a reflector, a test model, a laser displacement meter matrix, and a safety protection device as its core components. It can monitor and suppress the amplitude of the test model in a non-contact mode, and is particularly suitable for application scenarios where it is inconvenient to implement the device in a wind tunnel or where there is additional wiring inside the test model.

[0019] 2. The present invention uses a safety protection device consisting of a stabilizing bracket, roller assembly, stabilizing head, hydraulic cylinder, reversing valve, accumulator, etc. During the test, it takes corresponding actions according to the real-time state of the amplitude of the test model, which can quickly restore the test model in an unstable state to a stable state, and effectively protect the wind tunnel interior and the test model.

[0020] 3. This invention uses redundancy design and analysis of signals from multi-row laser displacement meter matrices to provide safety protection for the entire wind tunnel system through information interaction between the flutter control system and the wind tunnel control system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0022] Figure 2 This is a schematic diagram of the laser displacement gauge matrix arrangement;

[0023] Figure 3 This is a structural schematic diagram of the safety protection device;

[0024] Figure 4 This is a schematic diagram of the safety protection device suppressing the vibration of the test model before it is tested;

[0025] Figure 5 This is a schematic diagram showing the safety protection device suppressing the vibration of the test model;

[0026] Figure 6This is a data acquisition and control architecture diagram of the flutter measurement and control system;

[0027] Figure 7 This is a flowchart of the method of the present invention.

[0028] In the figure, 1-wind tunnel test section, 11-first sidewall, 12-second sidewall, 2-reflector, 3-test model, 31-trapezoidal groove, 4-laser displacement meter matrix, 5-safety protection device, 51-stabilizing bracket, 52-roller group, 53-stabilizing head, 54-hydraulic cylinder, 55-reversing valve, 56-accumulator, 57-hydraulic pump, 58-oil tank. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0030] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0031] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0032] Example 1: As Figures 1-6 As shown, a protective device for a continuous wind tunnel flutter test model includes a reflector 2, a laser displacement meter matrix 4, and a safety protection device 5. The two side walls of the wind tunnel test section 1 are defined as the first side wall 11 and the second side wall 12, respectively. The reflector 2 and the laser displacement meter matrix 4 are respectively arranged opposite to each other on the inner walls of the first side wall 11 and the second side wall 12. When the horizontal laser emitted by the laser displacement meter matrix 4 hits the reflector 2, it can return horizontally after being reflected by the reflector 2. The fixed end of the test model 3 is connected to the first side wall 11, and the free end of the test model 3 extends horizontally towards the second side wall 12. The end of the test model 3 facing the first side wall 11 is provided with a trapezoidal groove 31, and the first side wall 11 is provided with a notch adapted to the trapezoidal groove 31.

[0033] The safety protection device 5 includes a stabilizing bracket 51, a roller assembly 52, a stabilizing head 53, a hydraulic cylinder 54, and a hydraulic system. Two stabilizing brackets 51, arranged vertically, are fixed to the outer side of the first side wall 11. The roller assembly 52 is provided on the stabilizing bracket 51. The stabilizing head 53 is connected to the piston rod of the hydraulic cylinder 54. The upper and lower ends of the stabilizing head 53 are respectively in rolling cooperation with the two sets of roller assemblies 52. The hydraulic system drives the piston rod of the hydraulic cylinder 54 to extend and retract. When the piston rod of the hydraulic cylinder 54 extends, the stabilizing head 53 passes through the first side wall 11 and abuts against the bottom of the trapezoidal groove 31.

[0034] When test model 3 experiences flutter, it will vibrate violently. Based on the flutter amplitude that test model 3 needs to protect against, reflector 2 and laser displacement meter matrix 4 are placed on one side of test model 3. When test model 3 reaches the amplitude that needs to be protected, test model 3 will deform and block the laser beam emitted by laser displacement meter matrix 4. After laser displacement meter matrix 4 can no longer receive the laser beam reflected by reflector 2, it immediately sends a signal to control the hydraulic system to push the stabilizing head 53 towards test model 3 through hydraulic cylinder 54. Relying on the guidance provided by stabilizing bracket 51 and roller group 52, stabilizing head 53 can smoothly insert into trapezoidal groove 31 and abut against test model 3.

[0035] When the stabilizing head 53 is pressed against the fixed end of the test model 3, it can appropriately suppress the vertical vibration of the fixed end of the test model 3, thereby suppressing the overall amplitude of the test model 3 and playing a protective role.

[0036] The hydraulic system includes a directional valve 55 and a hydraulic pump 57. The directional valve 55 is a three-position four-way solenoid directional valve. The oil chambers on both sides of the hydraulic cylinder 54 are respectively connected to the A port and B port of the directional valve 55. The P port of the directional valve 55 is connected to the oil tank 58 through the hydraulic pump 57. The T port of the directional valve 55 is connected to the oil tank 58.

[0037] The hydraulic system also includes an accumulator 56. The P port of the reversing valve 55 is connected to the accumulator 56. If the hydraulic system is unexpectedly de-energized, the accumulator 56 drives the hydraulic cylinder 54 to perform a safety action, causing the stabilizing head 53 to insert into the trapezoidal groove 31 and press against the test model 3.

[0038] The laser displacement meter matrix 4 includes three rows of laser displacement meter groups. Each row of the laser displacement meter group includes several horizontally spaced laser displacement meters. In order from top to bottom, the vertical distance h1 between the first row of laser displacement meter groups and the test model 3 is 100% of the maximum positive amplitude H of the free end of the test model 3. The vertical distance h2 between the second row of laser displacement meter groups and the test model 3 is 90% of the maximum positive amplitude H of the free end of the test model 3. The vertical distance h3 between the third row of laser displacement meter groups and the test model 3 is 80% of the maximum positive amplitude H of the free end of the test model 3. The number of laser displacement meters in each row depends on the redundancy. It should be ensured that when the amplitude of the test model 3 reaches the installation height of the corresponding laser displacement meter group, the laser beam emitted by one or more laser displacement meters in that row of laser displacement meter groups is blocked by the test model 3 and cannot receive the laser beam reflected by the reflector 2. The laser beams received by the remaining laser displacement meters in that row of laser displacement meter groups from the reflector 2 are in a discontinuous state.

[0039] Each laser displacement gauge is connected to the flutter measurement and control system via a signal cable. The flutter measurement and control system is electrically connected to the alarm indicator light, manual emergency stop switch, reversing valve 55, and hydraulic pump 57, respectively. The wind tunnel measurement and control system is connected to the flutter measurement and control system via a network cable.

[0040] Example 2: Figures 1 to 7 As shown, a continuous wind tunnel flutter test model protection method is implemented based on the continuous wind tunnel flutter test model protection device described in Example 1, and includes the following steps:

[0041] Step 1: Start the experiment. Each laser displacement meter in the laser displacement meter matrix 4 emits a laser beam, and the data of the laser beam reflected by the reflector plate 2 is monitored in the laser displacement meter matrix 4.

[0042] Step 2: When the laser displacement meter group in the third row receives a discontinuous laser beam signal reflected by reflector 2, the flutter control system will trigger the alarm indicator light as a reminder.

[0043] When the laser displacement meter group in the second row receives a discontinuous laser beam signal reflected by reflector 2, the manual emergency stop switch is activated, and the flutter control system is in the state of receiving emergency stop signals. The operator can decide whether to open or close the manual emergency stop switch to perform an emergency stop operation.

[0044] When the laser displacement meter group receives a discontinuous laser beam signal reflected by the reflector plate 2, the flutter control system causes the safety protection device 5 to activate. The safety protection device 5 pushes the stabilizing head 53 against the test model 3 through the hydraulic cylinder 54, and at the same time sends a stop test command to the wind tunnel control system.

[0045] Step 3: End the experiment and stop monitoring the data of the laser displacement meter matrix.

[0046] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A protective device for a continuous wind tunnel flutter test model, characterized in that: Includes a reflector (2), a laser displacement meter matrix (4), and a safety protection device (5). The two side walls of the wind tunnel test section (1) are defined as the first side wall (11) and the second side wall (12), respectively. The reflector (2) and the laser displacement meter matrix (4) are respectively set on the inner walls of the first side wall (11) and the second side wall (12). The fixed end of the test model (3) is connected to the first side wall (11), and the free end of the test model (3) extends horizontally to the second side wall (12). The end of the test model (3) facing the first side wall (11) is provided with a trapezoidal groove (31), and the first side wall (11) is provided with a notch that matches the trapezoidal groove (31). The safety protection device (5) includes a stabilizing bracket (51), a roller assembly (52), a stabilizing head (53), a hydraulic cylinder (54), and a hydraulic system. Two stabilizing brackets (51) are respectively fixed to the outside of the first side wall (11). The roller assembly (52) is provided on the stabilizing bracket (51). The stabilizing head (53) is connected to the piston rod of the hydraulic cylinder (54). The upper and lower ends of the stabilizing head (53) are respectively in rolling cooperation with the two sets of roller assemblies (52). The hydraulic system drives the piston rod of the hydraulic cylinder (54) to extend and retract. When the piston rod of the hydraulic cylinder (54) extends, the stabilizing head (53) passes through the first side wall (11) and abuts against the bottom of the trapezoidal groove (31).

2. The protective device for a continuous wind tunnel flutter test model according to claim 1, characterized in that: The hydraulic system includes a directional valve (55) and a hydraulic pump (57). The directional valve (55) is a three-position four-way solenoid directional valve. The oil chambers on both sides of the hydraulic cylinder (54) are respectively connected to the A port and B port of the directional valve (55). The P port of the directional valve (55) is connected to the oil tank (58) through the hydraulic pump (57). The T port of the directional valve (55) is connected to the oil tank (58).

3. The protective device for a continuous wind tunnel flutter test model according to claim 2, characterized in that: The hydraulic system also includes an accumulator (56), and the P port of the directional valve (55) is connected to the accumulator (56).

4. The protective device for a continuous wind tunnel flutter test model according to claim 3, characterized in that: The laser displacement meter matrix (4) includes three rows of laser displacement meter groups. Each row of the laser displacement meter group includes several horizontally spaced laser displacement meters. In order from top to bottom, the vertical distance h1 between the first row of laser displacement meter groups and the test model (3) is 100% of the maximum positive amplitude H of the free end of the test model (3). The vertical distance h2 between the second row of laser displacement meter groups and the test model (3) is 90% of the maximum positive amplitude H of the free end of the test model (3). The vertical distance h3 between the third row of laser displacement meter groups and the test model (3) is 80% of the maximum positive amplitude H of the free end of the test model (3).

5. The protective device for a continuous wind tunnel flutter test model according to claim 4, characterized in that: Each laser displacement meter is connected to the flutter measurement and control system via a signal cable, and the flutter measurement and control system is electrically connected to the alarm indicator light, manual emergency stop switch, reversing valve (55) and hydraulic pump (57) respectively. The wind tunnel measurement and control system is connected to the flutter measurement and control system via a network cable.

6. A method for protecting a continuous wind tunnel flutter test model, based on the continuous wind tunnel flutter test model protection device described in claim 5, characterized in that, Includes the following steps: Step 1: Start the experiment. Each laser displacement meter in the laser displacement meter matrix (4) emits a laser beam. Monitor the data of the laser displacement meter matrix (4) received by the laser beam reflected by the reflector (2). Step 2: When the laser displacement meter group in the third row receives a discontinuous laser beam signal reflected by the reflector plate (2), the flutter control system will set the alarm indicator light to sound as a reminder. When the laser displacement meter group in the second row receives a laser beam signal reflected by the reflector (2) in a discontinuous state, the manual emergency stop switch is activated and the flutter control system is in the state of receiving emergency stop signals. The operator decides whether to open or close the manual emergency stop switch to perform an emergency stop operation. When the laser displacement meter group in the first row receives a discontinuous laser beam signal reflected by the reflector plate (2), the flutter control system causes the safety protection device (5) to activate and sends a stop test command to the wind tunnel control system at the same time. Step 3: End the experiment and stop monitoring the data of the laser displacement meter matrix.

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