Large-scale high-speed wind tunnel derivative measurement mechanism and test method

Abstract

The invention discloses a large-scale high-speed wind tunnel derivative measurement mechanism and a test method, and belongs to the technical field of aviation aerodynamic wind tunnel special tests. The problems that a large-scale wind tunnel is large in mechanism size, a long model supporting rod easily induces vibration of the supporting rod, and the test effect is affected are solved. The device comprises a supporting part, a vibration part and a driving part, a test model is arranged in a wind tunnel, the test model is slidably connected with the supporting part through the vibration part, the vibration part is connected with the driving part, the driving part is arranged outside the wind tunnel, and the vibration part and the supporting part are arranged inside the wind tunnel. According to the large-scale high-speed wind tunnel derivative measurement mechanism and the test method, the driving part is arranged outside the wind tunnel flow field, so that the space size of a support in the flow field is greatly reduced, and the flow field interference of the support on a test model is reduced. Length of the test model support rod is shortened, support rod rigidity is improved, and influence of support rod vibration on test results is reduced.

Description

Technical Field

[0001] This invention belongs to the field of special testing technology for aerodynamic wind tunnels, and particularly relates to a large-scale high-speed wind tunnel derivative measurement mechanism and testing method. Background Technology

[0002] The tail vibration dynamic derivative testing technique, which integrates the tail support rod with the model in a high-speed wind tunnel, is currently limited to linear-size wind tunnels, typically smaller than 1 meter. This is because existing tail vibration dynamic derivative structures employ an integral tail support, with the dynamic derivative mechanism mounted on a support bevel inside the wind tunnel, and the drive motor housed within the mechanism itself. The large tail dimension necessitates a long model support rod to minimize interference with the flow field. However, in large-scale wind tunnels, this large mechanism size and long model support rod can easily induce vibrations within the support rod itself, affecting the test results.

[0003] Therefore, this application proposes a large-scale high-speed wind tunnel derivative measurement mechanism and test method to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to address the problem that large-scale wind tunnel structures and long support rods can easily induce vibrations in the support rods themselves, affecting the experimental results. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0005] The technical solution of the present invention:

[0006] Option 1: A large-scale high-speed wind tunnel dynamic derivative measurement mechanism, comprising a support part, a vibration part and a drive part, wherein the test model is arranged inside the wind tunnel, the test model is slidably connected to the support part through the vibration part, the vibration part is connected to the drive part, the drive part is arranged outside the wind tunnel, and the vibration part and the support part are arranged inside the wind tunnel.

[0007] The support unit includes a support frame, an arc-shaped slide rail, and a slider. The support frame is placed horizontally inside the wind tunnel, and the two ends of the support frame are respectively connected to the wind tunnel windows on both sides of the wind tunnel. The arc-shaped slide rail is installed on the support frame, and a slider is connected to the arc-shaped slide rail. The vibration unit is slidably connected to the arc-shaped slide rail through the slider.

[0008] The drive unit includes a driver, a push-pull rod, and a force transmission rod. The cylinder of the driver is mounted on the outside of the wind tunnel by a hinge. The telescopic end of the driver is connected to one end of the push-pull rod, and the other end of the push-pull rod is hinged to the force transmission rod. The force transmission rod is connected to the vibration unit. The driver drives the push-pull rod to extend and retract along its axis, and drives the vibration unit to rotate around the center line of the arc-shaped slide rail through the force transmission rod.

[0009] Furthermore, the vibration unit includes a movable support, a model support rod, and a connecting part. One end of the movable support passes through the wind tunnel window and is connected to the force transmission rod, and the other end of the movable support is connected to the model support rod through the connecting part. The model support rod is used to support the test model.

[0010] Furthermore, the cross-section of the arc-shaped slide rail is U-shaped, the inner contour of the slider is adapted to the outer contour of the arc-shaped slide rail, and the slider and the arc-shaped slide rail are in clearance fit with a clearance of less than 0.05mm.

[0011] Furthermore, the rotation center line of the connecting part is O, the equilibrium angle of attack range of the test model is -4° to 12°, with the equilibrium angle of attack of 4° as the reference position, and the extension and retraction direction of the push-pull rod is perpendicular to the line OC connecting the center O and the junction of the force transmission rod and the movable bracket.

[0012] Option 2: A method for testing the dynamic derivative of a large-scale high-speed wind tunnel, which is based on the dynamic derivative measurement mechanism of a large-scale high-speed wind tunnel described in Option 1, and includes the following steps:

[0013] Step 1: Balance angle of attack position calibration, based on the balance angle of attack of each target. Determine the theoretical length of the push-pull rod of the driver. Control the extension and retraction length of the push-pull rod Measure the actual angle of attack of the test model The formula for calculating the angle of attack deviation is:

[0014]

[0015] when If the error exceeds the allowable range, adjust the length of the push-pull rod to... Measure the actual angle of attack again, and repeat the process until the angle of attack deviation meets the requirements;

[0016] Step 2: No-wind vibration test, according to the push-pull rod position corresponding to the calibrated equilibrium angle of attack. The push-pull rod is controlled to drive the test model to each specified equilibrium angle of attack position in sequence. At each position, the test model is controlled to vibrate for three seconds and measurement data is collected until the air vibration test at all equilibrium angles of attack is completed.

[0017] Step 3: Vibration test under blowing conditions. Start the wind tunnel. After the flow field inside the wind tunnel stabilizes, position the push-pull rods according to the calibrated equilibrium angles of attack. The push-pull rod is controlled to drive the test model to each designated equilibrium angle of attack position in sequence. At each position, the test model is controlled to vibrate for three seconds and measurement data is collected. After completing the test at all equilibrium angles of attack, the test model is controlled to return to the 0 angle of attack position and the wind tunnel is closed.

[0018] Furthermore, in step three, the wind tunnel is a high-speed wind tunnel with a length of one to two meters.

[0019] The present invention has the following beneficial effects:

[0020] 1. The large-scale high-speed wind tunnel derivative measurement mechanism of the present invention places the drive unit outside the wind tunnel flow field, significantly reducing the spatial size of the internal support and minimizing the interference of the support on the flow field of the test model. Correspondingly, the length of the test model support rod is shortened, the stiffness of the support rod is increased, and the influence of support rod vibration on the test results is reduced.

[0021] 2. The large-scale high-speed wind tunnel derivative measurement mechanism of the present invention adopts a fixed connection on both sides of the support frame of the support part. Compared with the traditional cantilever beam support method, it changes from single-point support to double-point support, thereby improving the support stiffness.

[0022] 3. The large-scale high-speed wind tunnel derivative measurement mechanism of the present invention adopts a direct drive method of the drive unit, which avoids the gap effect caused by the rotation conversion mechanism and has high vibration stability.

[0023] 4. The large-scale high-speed wind tunnel derivative measurement mechanism of the present invention can realize both the equilibrium angle of attack change of the test model and the sinusoidal oscillation of the test model at the equilibrium angle of attack, without the need for an additional angle of attack mechanism to realize the equilibrium angle of attack change of the test model. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a large-scale high-speed wind tunnel derivative measurement mechanism;

[0025] Figure 2 This is a schematic diagram showing the connection between the support structure and the wind tunnel window;

[0026] Figure 3 This is a schematic diagram showing the connection relationship between the vibration unit and the drive unit;

[0027] Figure 4 This is a schematic diagram showing the connection between the vibrating part and the force transmission rod;

[0028] Figure 5 This is a schematic diagram of the mechanism's operating principle when the angle of attack is 4°.

[0029] Figure 6 This is a schematic diagram of the mechanism's operation after the push-pull rod extends.

[0030] In the diagram: 1-Support section, 2-Vibration section, 3-Drive section, 4-Wind tunnel, 5-Wind tunnel rotating window, 6-Test model, 11-Support frame, 12-Arc-shaped slide rail, 13-Slider, 21-Modible bracket, 22-Model support rod, 23-Connecting section, 31-Driver, 32-Push-pull rod, 33-Force transmission rod. Detailed Implementation

[0031] 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.

[0032] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections (i.e., 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 threaded 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 always be found to achieve the 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 hinged connection can be chosen for detachable connections.

[0033] Example 1, combined with Figures 1-6 This embodiment describes a large-scale high-speed wind tunnel derivative measurement mechanism, which includes a support part 1, a vibration part 2, and a drive part 3. The test model 6 is arranged inside the wind tunnel 4. The test model 6 is slidably connected to the support part 1 through the vibration part 2. The vibration part 2 is connected to the drive part 3. The drive part 3 is arranged on the outside of the wind tunnel 4, and the vibration part 2 and the support part 1 are arranged on the inside of the wind tunnel 4.

[0034] The support part 1 includes a support frame 11, an arc-shaped slide rail 12, and a slider 13. The support frame 11 is placed horizontally inside the wind tunnel 4. The two ends of the support frame 11 are respectively connected to the wind tunnel windows 5 on both sides of the wind tunnel 4. The arc-shaped slide rail 12 is installed on the support frame 11, and the slider 13 is connected to the arc-shaped slide rail 12. The vibration part 2 is slidably connected to the arc-shaped slide rail 12 through the slider 13.

[0035] The drive unit 3 includes a driver 31, a push-pull rod 32, and a force transmission rod 33. The cylinder of the driver 31 is mounted on the outside of the wind tunnel 4 by a hinge. The telescopic end of the driver 31 is connected to one end of the push-pull rod 32, and the other end of the push-pull rod 32 is hinged to the force transmission rod 33. The force transmission rod 33 is connected to the vibration unit 2. The driver 31 drives the push-pull rod 32 to extend and retract along its axis, and drives the vibration unit 2 to rotate around the center line of the arc-shaped slide rail 12 through the force transmission rod 33.

[0036] The support frame 11 is made of high-strength aluminum alloy to ensure that its length is compatible with the spacing of the wind tunnel windows 5 on both sides of the wind tunnel 4; the arc-shaped slide rail 12 is made of stainless steel and is processed into an arc structure with a U-shaped cross section. The radius of the arc is designed according to the rotation requirements of the test model 6. The slider 13 is made of polytetrafluoroethylene, and its inner contour is fitted to the outer contour of the arc-shaped slide rail 12 with a fit gap of less than 0.05mm. The arc-shaped slide rail 12 is fixed to the support frame 11 with bolts, and the slider 13 is fitted on the arc-shaped slide rail 12 to ensure smooth sliding without jamming. The two ends of the support frame 11 are fixed to the wind tunnel windows 5 with flanges.

[0037] The movable support 21 is made of titanium alloy to ensure strength and light weight. The connecting part 23 is processed by forging and fixedly connected to the movable support 21 by welding. The model support rod 22 is connected to the connecting part 23 by thread, which facilitates the disassembly and replacement of test models 6 of different specifications.

[0038] The actuator 31 is a hydraulic actuator. The cylinder body is mounted on a bracket outside the wind tunnel 4 via a hinged support. The push-pull rod 32 is made of high-strength alloy steel. Both ends of the push-pull rod 32 are hinged to the telescopic end of the actuator 31 and the force transmission rod 33, respectively. The push-pull rod 32 transmits the push-pull force to the movable bracket 21 through the force transmission rod 33. The cylinder end of the actuator 31 is hinged, allowing the actuator 31 to rotate in the horizontal plane. During operation, the push-pull rod 32 extends and retracts along the axis of the actuator 31, while the actuator 31 rotates slightly around its hinged end.

[0039] When the actuator 31 extends the push-pull rod 32, it pushes the force transmission rod 33 upward. Since the push-pull rod 32 is fixedly connected to the movable bracket 21, the movable bracket 21 is constrained by the arc-shaped slide rail 12 and can only rotate around the center O of the connecting part 23. The force transmission rod 33 can only rotate, and correspondingly, the push-pull rod 32 and the force transmission rod 33 rotate relative to each other at the hinge point B. Simultaneously, the hinge point B shifts to... Due to Not on the line connecting points A and B, the actuator 31 needs to generate rotation about hinge point A. The extension and retraction of the push-pull rod 32 of the actuator 31 has a one-to-one correspondence with the rotation of the movable support 21, and the rotation of the movable support 21 is the change in the angle of attack of the test model 6. By controlling the extension and retraction of the push-pull rod 32 of the actuator 31, the angle of attack of the test model 6 can be directly controlled.

[0040] In the dynamic derivative test, the test model 6 is required to perform small-amplitude sinusoidal oscillations at a certain equilibrium angle of attack, usually 1°. The test state must correspond to different equilibrium angles of attack. During the test, the equilibrium angle of attack of the test model 6 needs to be changed, and oscillations are performed at different equilibrium angles of attack to obtain the dynamic derivative test results at different angles of attack.

[0041] Point C is the connection point between the force transmission rod 33 and the movable bracket 21, and point O is the center of the connection part 23. When the extension and retraction direction of the push-pull rod 32 is perpendicular to OC, the motion law of the push-pull rod 32 is consistent with the vibration law of the test model 6. The linear correspondence between the two is as follows:

[0042]

[0043] Experimental model 6 changes over time; The length of push-pull rod 32 changes over time; This is the proportionality coefficient;

[0044] The equilibrium angle of attack range of test model 6 is -4° to 12°. With an equilibrium angle of attack of 4° as the baseline, the push-pull rod 32 is perpendicular to OC. At other equilibrium angles of attack, the push-pull rod 32 is no longer perpendicular to OC, with a maximum deviation of 6°. At this point, the push-pull rod 32 undergoes sinusoidal vibration, and the oscillation law of test model 6 approximates a sine curve, satisfying the positive linearity requirement of the curve in dynamic derivative engineering experiments. This design simplifies the control of the driver 31, which performs standard sinusoidal oscillations, resulting in simple control and stable output.

[0045] Example 2, combined with Figures 1-6 This embodiment describes a method for testing the dynamic derivative of a large-scale high-speed wind tunnel, which includes the following steps:

[0046] Step 1: Calibrate the equilibrium angle of attack position, setting the target equilibrium angles of attack as -4°, 0°, 4°, 8°, and 12°; create a 3D model of the mechanism using CAD software, and calculate the theoretical length of the push-pull rod 32 corresponding to each target angle of attack. When the target balances the angle of attack The theoretical length at 4° =500mm, start the driver 31, and adjust the push-pull rod 32 to =500mm, the actual angle of attack of test model 6 was measured using a laser angle sensor. =3.85°, calculate the angle of attack deviation. =0.15°, exceeding the allowable error of ±0.1°; correct the length of push-pull rod 32. The actual angle of attack was measured again at 502mm. =4.02°, =0.02°, meeting the error requirement, record the calibration position. =502mm, repeat the above process to complete the calibration of the balanced angle of attack of all targets.

[0047] Step 2: Seamless air vibration test. Turn off wind tunnel 4 and control the actuator 31 to adjust the test model 6 to -4°, 0°, 4°, 8°, and 12° respectively according to the calibrated position. At each position, set the vibration frequency of the actuator 31 to 5Hz and the amplitude to ±1°, drive the test model 6 to vibrate for 3 seconds, collect the inertial force data of the test model 6 through the piezoelectric force sensor, collect the vibration acceleration data through the accelerometer, and store it in the data acquisition system. After all positions are tested, control the test model 6 to return to the 0 angle of attack position.

[0048] Step 3: Vibration test under wind conditions. Start wind tunnel 4 and set the wind speed to Ma=2.0. After the flow field stabilizes, adjust the test model 6 to the target equilibrium angle of attack according to the calibration position. At each position, drive the test model 6 to vibrate for 3 seconds according to the same vibration parameters as the air vibration test, with a frequency of 5Hz and an amplitude of ±1°. Simultaneously collect aerodynamic and vibration parameter data. After all positions are tested, control the test model 6 to return to the 0 angle of attack position, close wind tunnel 4, compare the wind test data with the air vibration test data, eliminate additional interference such as inertial force, and calculate the dynamic derivative of the test model 6.

[0049] This embodiment is merely an exemplary illustration of the present invention and does not limit its scope of protection. Those skilled in the art can make partial changes to it, 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 mechanism for measuring the dynamic derivative of a large-scale high-speed wind tunnel, characterized in that: It includes a support part (1), a vibration part (2) and a drive part (3). The test model (6) is arranged inside the wind tunnel (4). The test model (6) is slidably connected to the support part (1) through the vibration part (2). The vibration part (2) is connected to the drive part (3). The drive part (3) is arranged outside the wind tunnel (4). The vibration part (2) and the support part (1) are arranged inside the wind tunnel (4). The support part (1) includes a support frame (11), an arc-shaped slide rail (12) and a slider (13). The support frame (11) is placed horizontally inside the wind tunnel (4). The two ends of the support frame (11) are respectively connected to the wind tunnel windows (5) on both sides of the wind tunnel (4). The arc-shaped slide rail (12) is installed on the support frame (11). The slider (13) is connected to the arc-shaped slide rail (12). The vibration part (2) is slidably connected to the arc-shaped slide rail (12) through the slider (13). The drive unit (3) includes a driver (31), a push-pull rod (32) and a force transmission rod (33). The cylinder of the driver (31) is mounted on the outside of the wind tunnel (4) by a hinge. The telescopic end of the driver (31) is connected to one end of the push-pull rod (32), and the other end of the push-pull rod (32) is hinged to the force transmission rod (33). The force transmission rod (33) is connected to the vibration unit (2). The driver (31) drives the push-pull rod (32) to extend and retract along its axis, and drives the vibration unit (2) to rotate around the center line of the arc-shaped slide rail (12) through the force transmission rod (33).

2. The large-scale high-speed wind tunnel dynamic derivative measurement mechanism according to claim 1, characterized in that: The vibration part (2) includes a movable support (21), a model support rod (22) and a connecting part (23). One end of the movable support (21) passes through the wind tunnel window (5) and is connected to the force transmission rod (33). The other end of the movable support (21) is connected to the model support rod (22) through the connecting part (23). The model support rod (22) is used to support the test model (6).

3. The large-scale high-speed wind tunnel dynamic derivative measurement mechanism according to claim 2, characterized in that: The cross-section of the arc-shaped slide rail (12) is U-shaped. The inner contour of the slider (13) is adapted to the outer contour of the arc-shaped slide rail (12). The slider (13) and the arc-shaped slide rail (12) are in clearance fit, and the fit gap is less than 0.05mm.

4. The large-scale high-speed wind tunnel dynamic derivative measurement mechanism according to claim 3, characterized in that: The rotation center line of the connecting part (23) is O, and the equilibrium angle of attack range of the test model (6) is -4° to 12°. With the equilibrium angle of attack of 4° as the reference position, the extension and retraction direction of the push-pull rod (32) is perpendicular to the line OC connecting the center O, the force transmission rod (33), and the movable bracket (21).

5. A method for testing the dynamic derivative of a large-scale high-speed wind tunnel, the method being implemented based on the dynamic derivative measurement mechanism of a large-scale high-speed wind tunnel as described in claim 4, characterized in that... Includes the following steps: Step 1: Balance angle of attack position calibration, based on the balance angle of attack of each target. Determine the theoretical length of the push-pull rod (32) of the driver (31). Control the extension and retraction length of the push-pull rod (32) The actual angle of attack of the test model (6) was measured. The formula for calculating the angle of attack deviation is: ； Actual angle of attack Angle of attack balanced with target The difference, when If the error exceeds the allowable range, adjust the length of the push-pull rod (32) to... Measure the actual angle of attack again, and repeat the process until the angle of attack deviation meets the requirements; Step 2: No-wind vibration test, according to the position of the push-pull rod (32) corresponding to the calibrated equilibrium angle of attack. The push-pull rod (32) is controlled to drive the test model (6) to reach each specified equilibrium angle of attack position in sequence. At each position, the test model (6) is controlled to vibrate for three seconds and measurement data is collected until the air vibration test under all equilibrium angles of attack is completed. Step 3: Vibration test under blowing conditions. Start the wind tunnel (4). After the flow field inside the wind tunnel (4) stabilizes, position the push-pull rod (32) according to the calibrated position of each equilibrium angle of attack. Control the push-pull rod (32) to drive the test model (6) to reach each specified equilibrium angle of attack position in sequence. Control the test model (6) to vibrate for three seconds at each position and collect measurement data. After completing the test at all equilibrium angles of attack, control the test model (6) to return to the 0 angle of attack position and close the wind tunnel (4).

6. The method for testing the dynamic derivative of a large-scale high-speed wind tunnel according to claim 5, characterized in that: In step three, the wind tunnel (4) is a high-speed wind tunnel with a length of one to two meters.

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