Transsonic speed wind tunnel opening wall parameter adjusting system and transonic speed wind tunnel opening wall parameter adjusting method

Abstract

The invention discloses a transonic wind tunnel opening wall parameter adjusting system and method. The system comprises an inner wall plate, an outer wall plate, an elastic pipe, an air hole axial length adjusting mechanism and an air hole inclination angle adjusting mechanism. The inner wall plate and the outer wall plate are distributed in parallel, an inter-plate gap is reserved between the inner wall plate and the outer wall plate, the elastic pipe is located in the inter-plate gap, an inner cavity of a pipe body of the elastic pipe serves as an air hole, the outer wall plate is connected to the air hole axial length adjusting mechanism, and the air hole inclination angle adjusting mechanism is arranged on the inner wall plate and connected with the air hole axial length adjusting mechanism. Under different test incoming flow Mach numbers, the test section of the transonic wind tunnel can be always under the optimal flow field characteristic condition by adjusting the axial length and the inclination angle of the vent hole, and the method can be used for researching the flow characteristics of the test section of the transonic wind tunnel under different hole wall parameters and also can be used for researching the flow characteristics of the test section of the transonic wind tunnel under different hole wall parameters. A research result can be used as a theoretical basis for construction and debugging of a transonic wind tunnel test section hole wall, and the test precision of the model in a transonic wind tunnel can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of transonic wind tunnels, and in particular relates to a transonic wind tunnel opening wall parameter adjustment system and method. Background Art

[0002] At present, the pore form of the air permeable wall of the test section of transonic wind tunnels at home and abroad is mostly open wall, and the geometric parameters of the air holes on the open wall are designed according to the commonly used test Mach number, and the geometric parameters of the air holes are usually fixed.

[0003] The flow characteristics of the perforated wall in the transonic wind tunnel test section are complex. The function of the perforated wall is to extract the low-momentum fluid in the boundary layer under different pressure differences between the test section and the stationary chamber, thereby playing a role in regulating the static pressure of the test section flow. The vents can continue to expand and accelerate the airflow in the transonic wind tunnel test section, so that the airflow in the test section reaches low supersonic flow. The leading edge and trailing edge of the vents can generate expansion waves and barrier shock waves respectively, which can interact with the incident shock waves generated by the surface of the model in the transonic wind tunnel test section, thereby weakening and absorbing the shock waves.

[0004] However, different vent geometric parameters correspond to different opening wall flow characteristics and flow field distribution characteristics. Under fixed opening wall parameter conditions, different incoming flow Mach numbers will lead to differences in flow field distribution characteristics of the transonic wind tunnel test section. For example, at high subsonic speeds, the flow field uniformity of the test section when the vent is a straight hole is better than that of the test section when the vent is an inclined hole; at low supersonic speeds, due to the need to absorb shock waves, the test section can obtain better flow field distribution characteristics when the vent is an inclined hole.

[0005] It can be seen that the parameters of the air holes in the opening wall should be adjusted according to the Mach number of the incoming flow and the shock wave absorption capacity, so that the test section of the transonic wind tunnel can always have the best flow field characteristics. However, there is still a blank in the existing transonic wind tunnel technology regarding the case of adjusting the geometric parameters of the air holes in the opening wall, so it is imperative to design a technical solution that can meet the requirements of adjusting the geometric parameters of the air holes in the opening wall. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a transonic wind tunnel opening wall parameter adjustment system and method, which can realize the adjustment of the axial length of the air holes and the inclination angle of the air holes. Under different test flow Mach numbers, the axial length of the air holes and the inclination angle of the air holes can be adjusted to make the test section of the transonic wind tunnel always under the optimal flow field characteristic conditions. The system and method can be used to study the flow characteristics of the transonic wind tunnel test section under different opening wall parameters, and the research results can be used as a theoretical basis for the construction and debugging of the opening wall of the transonic wind tunnel test section. The test accuracy of the model in the transonic wind tunnel can also be improved.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a transonic wind tunnel opening wall parameter adjustment system, comprising an inner wall plate, an outer wall plate, an elastic tube, a first air hole axial length adjustment mechanism, a second air hole axial length adjustment mechanism and an air hole inclination angle adjustment mechanism; the inner wall plate and the outer wall plate are distributed in parallel, and an inter-plate gap is left between the inner wall plate and the outer wall plate; an inner circular opening is opened on the inner wall plate; an outer circular opening is opened on the outer wall plate; the elastic tube is located in the inter-plate gap, one end of the elastic tube is sealed and connected to the inner circular opening, and the other end of the elastic tube is sealed and connected to the outer circular opening, and the tube body cavity of the elastic tube serves as an air hole; the first air hole axial length adjustment mechanism and the second air hole axial length adjustment mechanism are arranged in parallel on the inner wall plate, and the outer wall plate is connected between the first air hole axial length adjustment mechanism and the second air hole axial length adjustment mechanism; the air hole inclination angle adjustment mechanism is arranged on the inner wall plate, and the air hole inclination angle adjustment mechanism is connected to the first air hole axial length adjustment mechanism.

[0008] The axial length adjustment mechanism of the first air vent includes a first swing plate, a first motor, a first lead screw and a first nut; one end of the first swing plate is hinged to the inner wall plate through a first ear seat, and the other end of the first swing plate is a free end; a first bearing seat is arranged on the hinged end plate body of the first swing plate, and a first adapter seat is arranged on the free end plate body of the first swing plate; the first motor is fixedly mounted on the first adapter seat; the first lead screw is distributed parallel to the first swing plate, one end of the first lead screw is rotatably connected to the first bearing seat, and the other end of the first lead screw is coaxially fixedly connected to the motor shaft of the first motor through a first coupling; the first nut is sleeved on the first lead screw, and a second ear seat is installed on the first nut; one end of the outer wall plate is hinged to the first nut through the second ear seat.

[0009] The axial length adjustment mechanism of the second air vent includes a second swing plate, a second motor, a second lead screw and a second nut; one end of the second swing plate is hinged to the inner wall plate through a third ear seat, the other end of the second swing plate is a free end, and the second swing plate is distributed in parallel with the first swing plate; a second bearing seat is provided on the hinged end plate body of the second swing plate, and a second adapter seat is provided on the free end plate body of the second swing plate; the first motor is fixedly mounted on the second adapter seat; the second lead screw is distributed in parallel with the second swing plate, one end of the second lead screw is rotatably connected to the second bearing seat, and the other end of the second lead screw is coaxially fixedly connected to the motor shaft of the second motor through a second coupling; the second nut is sleeved on the second lead screw, and a fourth ear seat is installed on the second nut; the other end of the outer wall plate is hinged to the second nut through the fourth ear seat.

[0010] The air vent inclination angle adjustment mechanism includes an electric cylinder, a support seat, a slider and a linear slide rail; the support seat is fixedly mounted on the inner wall plate, the electric cylinder is fixedly mounted on the top of the support seat, and the electric cylinder is distributed parallel to the inner wall plate; the linear slide rail is fixedly mounted on the first swing plate, the linear slide rail and the first lead screw are respectively located on both sides of the first swing plate, and the linear slide rail and the first lead screw are distributed parallel to each other; the slider is arranged on the linear slide rail, and a fifth ear seat is installed on the slider; the end of the power output rod of the electric cylinder is hinged to the slider through the fifth ear seat.

[0011] A method for adjusting parameters of a transonic wind tunnel opening wall adopts the transonic wind tunnel opening wall parameter adjustment system, specifically comprising:

[0012] ①, when only the axial length of the air vent is adjusted, the first motor and the second motor are started synchronously, driving the first lead screw and the second lead screw to rotate synchronously, thereby driving the first nut and the second nut to move linearly synchronously, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent reaches the set value;

[0013] ②. When only the inclination angle of the air vent is adjusted, the electric cylinder is started to drive the slider to move along the slide rail, and then drive the first swing plate to swing around the first ear seat hinge point. At this time, the first swing plate, the outer wall plate, the second swing plate and the inner wall plate form a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate moves synchronously, and the second swing plate swings around the third ear seat hinge point synchronously until the inclination angle of the elastic tube reaches the set value, but the inter-plate gap between the outer wall plate and the inner wall plate will also change. At this time, the first motor and the second motor are started synchronously to drive the first lead screw and the second lead screw to rotate synchronously, and then drive the first nut and the second nut to move linearly synchronously, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent is restored to the initial value;

[0014] ③. When both the axial length and the inclination angle of the air vent are adjusted, the electric cylinder is started to drive the slider to move along the slide rail, and then drive the first swing plate to swing around the first ear seat hinge point. At this time, the first swing plate, the outer wall plate, the second swing plate and the inner wall plate constitute a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate moves synchronously, and the second swing plate swings around the third ear seat hinge point synchronously until the inclination angle of the elastic tube reaches the set value; at the same time, the first motor and the second motor are started synchronously to drive the first lead screw and the second lead screw to rotate synchronously, and then drive the first nut and the second nut to move synchronously in a straight line, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent reaches the set value.

[0015] Beneficial effects of the present invention:

[0016] The transonic wind tunnel opening wall parameter adjustment system and method of the present invention can adjust the axial length of the air holes and the inclination angle of the air holes. Under different test flow Mach numbers, the test section of the transonic wind tunnel can always be under the optimal flow field characteristic conditions by adjusting the axial length of the air holes and the inclination angle of the air holes. It can be used to study the flow characteristics of the transonic wind tunnel test section under different opening wall parameters, and the research results can be used as a theoretical basis for the construction and debugging of the opening wall of the transonic wind tunnel test section. It can also improve the test accuracy of the model in the transonic wind tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a transonic wind tunnel hole wall parameter adjustment system (straight hole state 1) of the present invention;

[0018] Figure 2 It is a structural schematic diagram of a transonic wind tunnel hole wall parameter adjustment system (straight hole state 2) of the present invention;

[0019] Figure 3 It is a structural schematic diagram of a transonic wind tunnel hole wall parameter adjustment system (inclined hole state) of the present invention;

[0020] In the figure, 1 is an inner wall plate, 2 is an outer wall plate, 3 is an elastic tube, 4 is a gap between plates, 5 is an air vent, 6 is a first swing plate, 7 is a first motor, 8 is a first lead screw, 9 is a first nut, 10 is a first ear seat, 11 is a first bearing seat, 12 is a first adapter seat, 13 is a first coupling, 14 is a second ear seat, 15 is a second swing plate, 16 is a second motor, 17 is a second lead screw, 18 is a second nut, 19 is a third ear seat, 20 is a second bearing seat, 21 is a second adapter seat, 22 is a second coupling, 23 is a fourth ear seat, 24 is an electric cylinder, 25 is a support seat, 26 is a slider, 27 is a linear guide rail, and 28 is a fifth ear seat. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 3 As shown, a transonic wind tunnel hole wall parameter adjustment system comprises an inner wall plate 1, an outer wall plate 2, an elastic tube 3, a first air hole axial length adjustment mechanism, a second air hole axial length adjustment mechanism and an air hole inclination angle adjustment mechanism; the inner wall plate 1 and the outer wall plate 2 are arranged in parallel, and an inter-plate gap 4 is left between the inner wall plate 1 and the outer wall plate 2; an inner circular hole is opened on the inner wall plate 1; an outer circular hole is opened on the outer wall plate 2; the elastic tube 3 is located in the inter-plate gap 4, and one end of the elastic tube 3 is connected to the inner circular hole. The opening is sealed and connected, and the other end of the elastic tube 3 is sealed and connected to the outer circular opening, and the inner cavity of the elastic tube 3 serves as the air vent 5; the first air vent axial length adjustment mechanism and the second air vent axial length adjustment mechanism are arranged in parallel on the inner wall plate 1, and the outer wall plate 2 is connected between the first air vent axial length adjustment mechanism and the second air vent axial length adjustment mechanism; the air vent inclination angle adjustment mechanism is arranged on the inner wall plate 1, and the air vent inclination angle adjustment mechanism is connected to the first air vent axial length adjustment mechanism.

[0023] The axial length adjustment mechanism of the first air vent comprises a first swing plate 6, a first motor 7, a first lead screw 8 and a first nut 9; one end of the first swing plate 6 is hinged to the inner wall plate 1 through a first ear seat 10, and the other end of the first swing plate 6 is a free end; a first bearing seat 11 is provided on the hinged end plate body of the first swing plate 6, and a first adapter seat 12 is provided on the free end plate body of the first swing plate 6; the first motor 7 is fixedly mounted on the first adapter seat 12; the first lead screw 8 is distributed parallel to the first swing plate 6, one end of the first lead screw 8 is rotatably connected to the first bearing seat 11, and the other end of the first lead screw 8 is coaxially fixedly connected to the motor shaft of the first motor 7 through a first coupling 13; the first nut 9 is sleeved on the first lead screw 8, and a second ear seat 14 is installed on the first nut 9; one end of the outer wall plate 2 is hinged to the first nut 9 through the second ear seat 14.

[0024] The second air vent axial length adjustment mechanism includes a second swing plate 15, a second motor 16, a second lead screw 17 and a second nut 18; one end of the second swing plate 15 is hinged to the inner wall plate 1 through a third ear seat 19, and the other end of the second swing plate 15 is a free end, and the second swing plate 15 is parallel to the first swing plate 6; a second bearing seat 20 is provided on the hinged end plate body of the second swing plate 15, and a second adapter seat 21 is provided on the free end plate body of the second swing plate 15; the first motor 7 is fixedly mounted on the second adapter seat 21; the second lead screw 17 is parallel to the second swing plate 15, one end of the second lead screw 17 is rotatably connected to the second bearing seat 20, and the other end of the second lead screw 17 is coaxially fixedly connected to the motor shaft of the second motor 16 through a second coupling 22; the second nut 18 is sleeved on the second lead screw 17, and a fourth ear seat 23 is installed on the second nut 18; the other end of the outer wall plate 2 is hinged to the second nut 18 through the fourth ear seat 23.

[0025] The air vent inclination angle adjustment mechanism includes an electric cylinder 24, a support seat 25, a slider 26 and a linear slide rail 27; the support seat 25 is fixedly mounted on the inner wall plate 1, the electric cylinder 24 is fixedly mounted on the top of the support seat 25, and the electric cylinder 24 is distributed parallel to the inner wall plate 1; the linear slide rail 27 is fixedly mounted on the first swing plate 6, the linear slide rail 27 and the first lead screw 8 are respectively located on both sides of the first swing plate 6, and the linear slide rail 27 and the first lead screw 8 are distributed parallel to each other; the slider 26 is arranged on the linear slide rail 27, and a fifth ear seat 28 is installed on the slider 26; the end of the power output rod of the electric cylinder 24 is hinged to the slider 26 through the fifth ear seat 28.

[0026] A method for adjusting parameters of a transonic wind tunnel opening wall adopts the transonic wind tunnel opening wall parameter adjustment system, specifically comprising:

[0027] ①, when only the axial length of the air vent 5 is adjusted, the first motor 7 and the second motor 16 are started synchronously, driving the first screw 8 and the second screw 17 to rotate synchronously, thereby driving the first nut 9 and the second nut 18 to move linearly synchronously, thereby driving the outer wall plate 2 to move, so that the inter-plate gap 4 between the outer wall plate 2 and the inner wall plate 1 changes, and finally the axial length of the elastic tube 3 changes until the axial length of the air vent 5 reaches the set value;

[0028] ②, when only the inclination angle of the air vent 5 is adjusted, the electric cylinder 24 is started to drive the slider 26 to follow along the slide rail 27, and then drive the first swing plate 6 to swing around the hinge point of the first ear seat 10. At this time, the first swing plate 6, the outer wall plate 2, the second swing plate 15 and the inner wall plate 1 constitute a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate 2 moves synchronously, and the second swing plate 15 swings around the hinge point of the third ear seat 19 synchronously until the inclination angle of the elastic tube 3 reaches the set value, but the inter-plate gap 4 between the outer wall plate 2 and the inner wall plate 1 will also change. At this time, the first motor 7 and the second motor 16 are started synchronously to drive the first screw 8 and the second screw 17 to rotate synchronously, and then drive the first nut 9 and the second nut 18 to move linearly synchronously, thereby driving the outer wall plate 2 to move, so that the inter-plate gap 4 between the outer wall plate 2 and the inner wall plate 1 changes, and finally the axial length of the elastic tube 3 changes until the axial length of the air vent 5 returns to the initial value;

[0029] ③. When adjusting both the axial length and the inclination angle of the air vent 5, the electric cylinder 24 is started to drive the slider 26 to follow along the slide rail 27, and then drive the first swing plate 6 to swing around the hinge point of the first ear seat 10. At this time, the first swing plate 6, the outer wall plate 2, the second swing plate 15 and the inner wall plate 1 constitute a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate 2 moves synchronously, and the second swing plate 15 swings around the hinge point of the third ear seat 19 synchronously until the inclination angle of the elastic tube 3 reaches the set value; at the same time, the first motor 7 and the second motor 16 are started synchronously to drive the first lead screw 8 and the second lead screw 17 to rotate synchronously, and then drive the first nut 9 and the second nut 18 to move linearly synchronously, thereby driving the outer wall plate 2 to move, so that the inter-plate gap 4 between the outer wall plate 2 and the inner wall plate 1 changes, and finally the axial length of the elastic tube 3 changes until the axial length of the air vent 5 reaches the set value.

[0030] Take the adjustment of the test section of a transonic wind tunnel to the optimal flow field characteristic conditions under different test flow Mach numbers as an example.

[0031] In this embodiment, the test incoming flow Mach number is first set to 0.803, the aperture of the air hole 5 is set to 2 mm, the initial value of the inclination angle of the air hole 5 is set to 30°, and the initial value of the axial length of the air hole 5 is set to 1 mm.

[0032] Then, the transonic wind tunnel was started to measure the Mach number deviation and Mach number root mean square deviation in the initial state. Then, the inclination angle of the air vent 5 was adjusted to 45°, 60° and 75° in turn, and the Mach number deviation and Mach number root mean square deviation at the corresponding inclination angles were recorded simultaneously. Then, all the recorded Mach number deviations and Mach number root mean square deviations were compared, and finally, the inclination angle of the air vent 5 corresponding to the minimum Mach number deviation and Mach number root mean square deviation was taken as the optimal value.

[0033] In this embodiment, the inclination angle of the air hole 5 is 60° as the optimal value. On this basis, the optimal value of the axial length of the air hole 5 is further determined, and the axial length of the air hole 5 is adjusted to 2 mm, 4 mm and 8 mm in turn, and the Mach number deviation and the Mach number root mean square deviation under the corresponding axial length are recorded synchronously, and then all the recorded Mach number deviations and Mach number root mean square deviations are compared, and finally the inclination angle of the air hole 5 corresponding to the minimum Mach number deviation and Mach number root mean square deviation is taken as the optimal value, and the optimal value of the axial length of the air hole 5 in this embodiment is 8 mm.

[0034] Similarly, when the test flow Mach number changes, the optimal value of the inclination angle and the optimal value of the axial length of the air hole 5 under different test flow Mach numbers can be obtained by simply operating in the above manner. Finally, the obtained optimal value data can be used as the optimal transonic wind tunnel opening wall parameters.

[0035] The solutions in the embodiments are not intended to limit the protection scope of the present invention. All equivalent implementations or changes that do not deviate from the present invention are included in the protection scope of the present invention.

Claims

1. A transonic wind tunnel opening wall parameter adjustment system, characterized in that: It comprises an inner wall plate, an outer wall plate, an elastic tube, a first air hole axial length adjustment mechanism, a second air hole axial length adjustment mechanism and an air hole inclination angle adjustment mechanism; the inner wall plate is arranged in parallel with the outer wall plate, and an inter-plate gap is left between the inner wall plate and the outer wall plate; an inner circular opening is provided on the inner wall plate; an outer circular opening is provided on the outer wall plate; the elastic tube is located in the inter-plate gap, one end of the elastic tube is sealedly connected to the inner circular opening, and the other end of the elastic tube is sealedly connected to the outer circular opening, and the inner cavity of the tube body of the elastic tube serves as an air hole; the first air hole axial length adjustment mechanism and the second air hole axial length adjustment mechanism are arranged in parallel on the inner wall plate, and the outer wall plate is connected between the first air hole axial length adjustment mechanism and the second air hole axial length adjustment mechanism; the air hole inclination angle adjustment mechanism is arranged on the inner wall plate, and the air hole inclination angle adjustment mechanism is connected to the first air hole axial length adjustment mechanism.

2. A transonic wind tunnel opening wall parameter adjustment system according to claim 1, characterized in that: The axial length adjustment mechanism of the first air vent includes a first swing plate, a first motor, a first lead screw and a first nut; one end of the first swing plate is hinged to the inner wall plate through a first ear seat, and the other end of the first swing plate is a free end; a first bearing seat is arranged on the hinged end plate body of the first swing plate, and a first adapter seat is arranged on the free end plate body of the first swing plate; the first motor is fixedly mounted on the first adapter seat; the first lead screw is distributed parallel to the first swing plate, one end of the first lead screw is rotatably connected to the first bearing seat, and the other end of the first lead screw is coaxially fixedly connected to the motor shaft of the first motor through a first coupling; the first nut is sleeved on the first lead screw, and a second ear seat is installed on the first nut; one end of the outer wall plate is hinged to the first nut through the second ear seat.

3. A transonic wind tunnel opening wall parameter adjustment system according to claim 2, characterized in that: The axial length adjustment mechanism of the second air vent includes a second swing plate, a second motor, a second lead screw and a second nut; one end of the second swing plate is hinged to the inner wall plate through a third ear seat, the other end of the second swing plate is a free end, and the second swing plate is distributed in parallel with the first swing plate; a second bearing seat is provided on the hinged end plate body of the second swing plate, and a second adapter seat is provided on the free end plate body of the second swing plate; the first motor is fixedly mounted on the second adapter seat; the second lead screw is distributed in parallel with the second swing plate, one end of the second lead screw is rotatably connected to the second bearing seat, and the other end of the second lead screw is coaxially fixedly connected to the motor shaft of the second motor through a second coupling; the second nut is sleeved on the second lead screw, and a fourth ear seat is installed on the second nut; the other end of the outer wall plate is hinged to the second nut through the fourth ear seat.

4. A transonic wind tunnel opening wall parameter adjustment system according to claim 3, characterized in that: The air vent inclination angle adjustment mechanism includes an electric cylinder, a support seat, a slider and a linear slide rail; the support seat is fixedly mounted on the inner wall plate, the electric cylinder is fixedly mounted on the top of the support seat, and the electric cylinder is distributed parallel to the inner wall plate; the linear slide rail is fixedly mounted on the first swing plate, the linear slide rail and the first lead screw are respectively located on both sides of the first swing plate, and the linear slide rail and the first lead screw are distributed parallel to each other; the slider is arranged on the linear slide rail, and a fifth ear seat is installed on the slider; the end of the power output rod of the electric cylinder is hinged to the slider through the fifth ear seat.

5. A method for adjusting the parameters of a transonic wind tunnel opening wall, using the transonic wind tunnel opening wall parameter adjustment system according to claim 4, characterized in that: Specifically: ①, when only the axial length of the air vent is adjusted, the first motor and the second motor are started synchronously, driving the first lead screw and the second lead screw to rotate synchronously, thereby driving the first nut and the second nut to move linearly synchronously, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent reaches the set value; ②. When only the inclination angle of the air vent is adjusted, the electric cylinder is started to drive the slider to move along the slide rail, and then drive the first swing plate to swing around the first ear seat hinge point. At this time, the first swing plate, the outer wall plate, the second swing plate and the inner wall plate form a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate moves synchronously, and the second swing plate swings around the third ear seat hinge point synchronously until the inclination angle of the elastic tube reaches the set value, but the inter-plate gap between the outer wall plate and the inner wall plate will also change. At this time, the first motor and the second motor are started synchronously to drive the first lead screw and the second lead screw to rotate synchronously, and then drive the first nut and the second nut to move linearly synchronously, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent is restored to the initial value; ③. When both the axial length and the inclination angle of the air vent are adjusted, the electric cylinder is started to drive the slider to move along the slide rail, and then drive the first swing plate to swing around the first ear seat hinge point. At this time, the first swing plate, the outer wall plate, the second swing plate and the inner wall plate constitute a parallelogram mechanism. Under the transmission action of the parallelogram mechanism, the outer wall plate moves synchronously, and the second swing plate swings around the third ear seat hinge point synchronously until the inclination angle of the elastic tube reaches the set value; at the same time, the first motor and the second motor are started synchronously to drive the first lead screw and the second lead screw to rotate synchronously, and then drive the first nut and the second nut to move synchronously in a straight line, thereby driving the outer wall plate to move, so that the inter-plate gap between the outer wall plate and the inner wall plate changes, and finally the axial length of the elastic tube changes until the axial length of the air vent reaches the set value.

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