A combined damper device for parachute test wind tunnel

Abstract

The application provides a parachute test wind tunnel combined damping device, which comprises an airflow collector, a damping ring, a support section, damping hole cover plate one, damping hole cover plate two, flange plate one, an annular rubber pad, damping hole one, damping hole two, flange plate three and flange plate four. The airflow collector is a tubular structure, the front part of which is a backflow port in the form of a bell mouth. Flange plate one, the support section, flange plate two, the annular rubber pad, flange plate three, the damping ring, flange plate four and the airflow collector are coaxially and concentrically fixedly connected in sequence. The damping ring is provided with a plurality of left and right matrix distributed damping holes one and damping holes two. The damping holes one and the damping holes two are respectively provided with the damping hole cover plate one and the damping hole cover plate two which cover part of the number of the damping holes one and the damping holes two. The damping device improves the safety of continuous high dynamic pressure wind tunnel resistance test of various flexible body products, and improves the operation safety and test data repeatability of parachute wind tunnel test.

Description

Technical Field

[0001] This invention belongs to the field of parachute testing technology and relates to a combined vibration reduction device for parachute testing wind tunnels. Background Technology

[0002] With the development of emergency flotation equipment for various types of military aircraft and helicopters in my country, parachutes and flotation devices have evolved from single products into a specialized product series. Due to the different flight envelopes and operational requirements of the supporting products for various aircraft types, the test wind speed requirements for airflow resistance in the installed state and airflow blowing in the deployed state are quite diverse. Open-type wind tunnels, due to their open test sections facilitating the installation of large-frame immersion fixtures, have become an excellent test platform for airflow resistance in the installed state and airflow blowing in the deployed state of various flotation devices. Due to the flexible structure of the float, its aerodynamic shape undergoes abrupt changes during airflow blowing. These abrupt changes lead to nonlinear phenomena in the surface velocity around the float, causing non-stationary airflow pulsations in the return flow section. Because the non-stationary airflow generated during the flexible test piece test flows out as a jet from the exit of the contraction section, is collected by the collector after passing through the test section, and the ejected gas interacts with the stationary air in the chamber to generate a shear layer, the shear layer shearing off creates vortex structures and a certain frequency of shearing vortices. Due to the presence of vortices, the jet shear layer and shedding vortices are in an unsteady state. This unstable aerodynamic field acts as an excitation source and interacts with the sump chamber, collector, wind tunnel structure, and the pulsation of the return airflow within the tunnel, ultimately producing a periodic resonance phenomenon at a certain frequency, around 20Hz. Multiple rounds of testing show that there are generally two flutter points within the wind speed envelope range of 0–100 m / s. The pulsation occurs at lower test wind speeds, disappears as the wind speed increases, and recurs when the wind speed increases to a higher flutter point. Therefore, conducting continuous high dynamic pressure wind tunnel tests on open-type wind tunnels poses a high risk to wind tunnel operation safety.

[0003] Currently, in the field of wind tunnel testing, wind tunnel designers generally eliminate the excitation frequency of commonly used wind speed points in the wind tunnel by adjusting the jet excitation frequency of the test section in order to study low-frequency flutter phenomena. Existing technical measures mainly include: 1) using vortex generators. Thin metal or hard plastic sheets are placed at the nozzle outlet; 2) opening the sump chamber top cover to ensure communication between the sump chamber and the outside atmosphere; 3) installing angled side guide plates at the wind tunnel collection inlet. These are used to close the gap between the upper guide plate and the side guide plate formed by adjusting the angle, reducing reflected airflow downstream of the sump chamber and thus lowering the low-frequency flutter amplitude; 4) adjusting the throat gap at the collection inlet. Gap widths of different widths are used between the collection inlet and the wall of the wind tunnel sump chamber, and experimental results have shown that this gap effectively suppresses the low-frequency flutter amplitude of the sump chamber. Existing technologies for eliminating tunnel resonance have the following shortcomings: 1) Adding baffles to the nozzle can easily generate high-frequency noise; 2) Arranging angled side guides at the collection port requires multiple iterations through testing, resulting in a long construction period; 3) The presence of multiple ventilation holes in the cavity structure, connected to the air duct and sump chamber, leads to greater energy loss and higher wind tunnel operating efficiency. Furthermore, during flexible body blowing tests, the wind speed in the test section fluctuates greatly due to the disturbance of unsteady feedback turbulence, resulting in poor consistency of test conditions.

[0004] In summary, existing technologies suffer from technical problems such as large energy loss in open-type parachute test wind tunnels, high risk of continuous operation under high dynamic pressure, and high noise levels. Summary of the Invention

[0005] Purpose of the invention: This invention provides a combined vibration damping device that is low in cost, has low energy loss, low flow field disturbance, and high safety, and is applicable to parachute test wind tunnels, thereby improving the safety of continuous high dynamic pressure wind tunnel impact tests for various flexible products.

[0006] Invention technical solution: A combined vibration damping device for a parachute test wind tunnel, comprising an airflow collector, a vibration damping ring, a support section, a vibration damping hole cover plate one, a vibration damping hole cover plate two, a flange one, an annular rubber gasket, a vibration damping hole one, a vibration damping hole two, a flange three, and a flange four. The airflow collector is a tubular structure with a flared return port at its front. Flange one, flange two, annular rubber gasket, flange three, and vibration damping ring four are axially provided with connecting through holes. Flange one, support section, flange two, and annular rubber gasket are sequentially connected... Rubber pads, flange three, vibration damping ring, and flange four are coaxially and concentrically fixedly connected to the airflow collector. The vibration damping ring is provided with multiple vibration damping holes one and two distributed in a left-right matrix. Vibration damping holes one and two are respectively provided with vibration damping hole cover plates one and two covering a portion of them. Annular rubber pads are provided between the airflow collector and the support section, between the support section and the vibration damping ring, between flange one and flange two, and between flange three and flange four. The connections are made using standard fastening bolts.

[0007] In the above scheme, there are eighteen vibration damping holes one and eighteen vibration damping holes two. The spacing of vibration damping holes one is one-twenty-third of the circumference of the vibration damping ring, and the spacing of vibration damping holes two is one-sixteenth of the circumference of the vibration damping ring. Vibration damping hole cover plate one is fixed on vibration damping holes one at intervals.

[0008] In the above scheme, the vibration damping device also includes vibration damping hole cover plate screws and locking nuts and vibration damping hole cover screw pads. The vibration damping hole cover plate covers the vibration damping hole and is fastened by the vibration damping hole cover plate screws and locking nuts and vibration damping hole cover screw pads.

[0009] In the above scheme, the flange is provided with two positioning through holes and twenty-four connecting through holes for connecting with the vibration damping ring. The two positioning through holes are distributed vertically, one of which is at a 15° angle to the center normal of the airflow collector, and the other positioning hole is at a 165° angle to the center normal of the airflow collector.

[0010] In the above scheme, the vibration damping device also includes a rectangular vibration damping ring reinforcing frame one and a rectangular vibration damping ring reinforcing frame two, which are respectively welded to vibration damping hole one and vibration damping hole two.

[0011] In the above scheme, the vibration reduction device also includes a support, which is an I-shaped semi-circular support seat. The upper end and the lower semi-circular arc of the support section are circumferentially welded through the ring reinforcement of the support section. The two support legs are connected to the support foundation of the wind tunnel test hall through anchor bolts.

[0012] In the above scheme, the area of ​​a single vibration damping hole one is 1 / 50 of the nozzle area of ​​the test section, and the area of ​​a single vibration damping hole two is 7 / 100 of the nozzle area of ​​the test section.

[0013] In the above scheme, a flange II is provided at the front and rear of the vibration damping ring, and two positioning through holes are provided on the front and rear flange II respectively. The two positioning through holes are distributed vertically. One positioning through hole is at a 15° angle to the center normal of the vibration damping ring, and the other positioning hole is at a 165° angle to the center normal of the vibration damping ring. The front flange II of the vibration damping ring is provided with twenty-four through holes for connecting with the original first diffuser section of the wind tunnel, and the rear flange II is provided with eighteen through holes for connecting with the front flange III of the support section.

[0014] In the above scheme, the vibration damping device also includes a horn-shaped reinforcing rib, which is arranged circumferentially on the outer contour surface of the airflow collector and welded to the outer contour surface of the airflow collector.

[0015] In the above scheme, the vibration damping device also includes a support section ring reinforcing rib, which is a ring-shaped reinforcing rib and is ring-welded to the support section.

[0016] The advantages and beneficial effects of this invention are as follows: This invention employs a combination of distributed vibration damping holes of varying sizes and a large curved surface airflow collector to mitigate vibration phenomena. This buffers the pulsating pressure difference acting inside and outside the diffuser section's tunnel wall, thereby reducing structural vibrations caused by the impact of free jet vortices on the closed portion of the tunnel. The vibration damping holes are located in the tunnel system's recirculation area downstream of the open test section. These holes buffer and balance the pulsating pressure difference acting inside and outside the first diffuser section's tunnel wall, thus reducing structural vibrations caused by the impact of free jet vortices on the solid tunnel wall. The vibration damping holes also reduce the energy of pressure pulsating waves within the airflow, thereby altering the resonant frequency and weakening the resonant energy to some extent. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a half-section front view of the present invention;

[0019] Figure 3 This is a front view schematic diagram of the present invention;

[0020] Figure 4 This is an enlarged cross-sectional view of the assembly of flange 2, flange 3 and annular rubber gasket of the present invention;

[0021] Figure 5 This is an assembly diagram of the support segment ring reinforcing rib, airflow collector, and support of the present invention;

[0022] Figure 6 This is a schematic diagram of the assembly of the airflow collector and flange 1 of the present invention;

[0023] Figure 7 This is a schematic diagram showing the vibration damping hole one and vibration damping hole two of the present invention unfolded in the vibration damping ring;

[0024] Figure 8 This is a partially enlarged schematic diagram of the assembly of the rectangular vibration damping ring reinforcing frame one and the rectangular vibration damping ring reinforcing frame two with the vibration damping ring of the present invention;

[0025] Figure 9 This is a partial cross-sectional schematic diagram showing the assembly of the vibration damping hole cover plate 1, vibration damping hole cover plate 2, locking nut 1, locking nut 2, vibration damping hole screw 1, vibration damping hole screw 2, and vibration damping hole cover plate screw pad, etc. of the present invention.

[0026] Among them, 1-airflow collector, 2-vibration damping ring, 3-support section, 4-support, 5-vibration damping hole cover plate one, 6-vibration damping hole cover plate two, 7-flange one, 8-rectangular vibration damping ring reinforcing frame one, 9-rectangular vibration damping reinforcing frame two, 10-vibration damping hole cover plate screw one, 11-vibration damping hole cover plate screw two, 12-locking nut on, 13-locking nut two, 14-vibration damping hole cover plate screw pad, 15-support section ring reinforcing rib, 16-ring rubber pad, 17-vibration damping hole one, 18-vibration damping hole two, 19-flange two, 20-flange three, 21-flange four, 22-trumpet-shaped reinforcing rib. Detailed Implementation

[0027] The present invention will be further described in detail below through specific embodiments:

[0028] A combined vibration damping device for a parachute test wind tunnel includes an airflow collector 1, a vibration damping ring 2, a support section 3, a support 4, a vibration damping hole cover plate 1 5, a vibration damping hole cover plate 2 6, a flange 1 7, a rectangular vibration damping ring reinforcing frame 1 8, a rectangular vibration damping reinforcing frame 2 9, a vibration damping hole cover plate screw 1 10, a vibration damping hole cover plate screw 2 11, a locking nut 1 12, a locking nut 2 13, a vibration damping hole cover plate screw washer 14, a support section ring reinforcing rib 15, an annular rubber pad 16, a vibration damping hole 1 17, a vibration damping hole 2 18, a flange 2 19, a flange 3 20, a flange 4 21, and a trumpet-shaped reinforcing rib 22.

[0029] The airflow collector 1 is a return component used to collect the jet stream from the nozzle. It is shaped like a steel, irregularly shaped tube with a flared return port at the front. This reduces the flutter effect caused by uncollected airflow blowing through the wind tunnel, lowers flutter energy, and shifts the vibration frequency. The maximum diameter of the airflow collector 1 is 1.56 times the diameter of the wind tunnel nozzle. The airflow collector 1 and flange 7 are positioned using a ring weld for coaxial and concentric installation with the support section 3, improving airflow collection efficiency. A flange 7 is located at the rear of the airflow collector 1. Flange 7 has two positioning through holes, one vertically spaced. One positioning through hole is at a 15° angle to the center normal of the airflow collector 1, and the other is at a 165° angle. Additionally, flange 7 has 24 connection through holes for connecting to the damping ring 2.

[0030] The damping ring 2 is a steel tubular component designed to reduce structural vibrations caused by the impact of free jet vortices on the enclosed portion of the tunnel at corresponding wind speed points. It buffers and balances the pulsating pressure difference between the inside and outside of the tunnel wall in the first diffusion section. Eighteen damping holes (17) and eighteen damping holes (18) are evenly distributed around its circumference. The area of ​​a single damping hole (17) is 1 / 50 of the nozzle area of ​​the test section, and the area of ​​a single damping hole (17) is 7 / 100 of the nozzle area of ​​the test section. The eighteen damping holes (17) and eighteen damping holes (18) are distributed in a left-right matrix on the damping ring 2. The taper of the inner flow channel of the damping ring 2 is 1:10. A flange 219 is provided at the front and rear of the vibration damping ring 2. Two positioning through holes are provided on the front and rear flanges 219 respectively. The two positioning through holes are distributed vertically. One positioning through hole is at a 15° angle to the center normal of the vibration damping ring 2, and the other positioning hole is at a 165° angle to the center normal of the vibration damping ring 2. The front flange 219 of the vibration damping ring 2 is provided with 24 through holes for connecting with the original first diffuser section of the wind tunnel, and the rear flange is provided with 18 through holes for connecting with the front flange 320 of the support section (3).

[0031] Support section 3 is a special-shaped steel tubular component designed to mitigate the vortex morphology and shearing vortex frequency generated by the interaction between the collected gas and the still air in the chamber. It is used to connect the airflow collector 1 and the vibration damping ring 2. Support section 3 and flange 2 19 are positioned by ring welding. It is used for coaxial and concentric installation with the vibration damping ring 2 to reduce the shearing frequency and alleviate structural vibration. The taper of the inner flow channel of support section 3 is 1:10. A flange 3 20 is provided at the front and rear of support section 3. Two positioning through holes are provided on the front and rear flange 3 20 respectively. The two positioning through holes are distributed vertically. One positioning through hole is at 15° with the center normal of support section 3, and the other positioning hole is at 165° with the center normal of support section 3. The front flange of support section 3 is provided with 18 connecting through holes for connecting with the vibration damping ring 2, and the rear flange is provided with 24 through holes for connecting with the airflow collector (1) flange 17.

[0032] Support 4 is an I-shaped semi-circular support. It serves as a support for support segment 3 and is circumferentially welded to the lower semi-circular arc of support segment 3 via the support segment's ring reinforcing rib 15. This ensures accurate positioning and fixation of support segment 3 to the equipment foundation of the combined vibration damping device. The two support legs of support 4 are connected to the support foundation of the wind tunnel test hall via anchor bolts, increasing the overall connection strength of the vibration damping device and ensuring the coaxiality of the various components.

[0033] The vibration damping hole cover plate 5 is a square cover plate, which is fastened to the vibration damping hole 17 in the vibration damping ring 2 by four vibration damping hole cover plate screws 10, vibration damping hole cover plate screw washers 14, and locking nuts 12. The assembly form is intermittent. This allows for optimal adjustment of the number, size, and layout of the large ventilation openings on the side of the vibration damping ring 2. Measurement data are compared and analyzed to obtain the relationships and influence values ​​of various factors. The vibration damping hole cover plate 5 is a thin, lightweight square steel plate, with its length and width dimensions being 1.1 times the length and width of the vibration damping hole 17. The vibration damping hole cover plate 5 has four matrix-distributed through holes at its four corners.

[0034] The vibration damping hole cover plate 26 is a rectangular cover plate, which is fastened to the vibration damping hole 28 in the vibration damping ring 2 by four vibration damping hole cover plate screws 211, vibration damping hole cover plate screw washers 14, and locking nuts 213. The assembly form is intermittent. It can achieve optimal adjustment of the number, size, and layout of the small ventilation openings on the side of the vibration damping ring 2. The measurement data is compared and analyzed to obtain the relationship between various factors and their influence values. The vibration damping hole cover plate 26 is a thin rectangular steel plate, and its length and width are 1.1 times the length and width of the vibration damping hole 28. The vibration damping hole cover plate 26 has four matrix-distributed through holes at the four corners.

[0035] Flange 7 is a common type of flange structure connector, which is equipped with 24 holes for connecting to the vibration damping ring 2.

[0036] A rectangular vibration damping ring reinforcing frame 8 is disposed around each vibration damping hole 17 in the vibration damping ring 2, improving the overall structural strength of the vibration damping hole 17 and reducing the vibration frequency of the vibration damping device under high dynamic pressure conditions. The rectangular vibration damping ring reinforcing frame 8 is a welded component with annular reinforcing ribs, respectively disposed around each vibration damping hole 17, improving the vibration resistance and overall rigidity of the vibration damping hole 17. The rectangular vibration damping ring reinforcing frame 8 is connected to the flange 19 by welding.

[0037] The rectangular vibration damping ring reinforcing frame 9 is a welded component with annular reinforcing ribs, which are respectively arranged around each vibration damping hole 17 to improve the vibration resistance and overall rigidity of the vibration damping hole 18. The rectangular vibration damping ring reinforcing frame 9 is connected to the flange 20 by welding.

[0038] A rectangular damping ring reinforcement frame 29 is installed around each damping hole 28 of the damping ring 2 to improve the overall structural strength of the damping hole 28 and reduce the vibration frequency of the damping device under low dynamic pressure conditions. The damping hole cover plate screw 10 is an anti-loosening screw that permanently connects the damping hole cover plate 5 to the damping hole 17 through an embedded connection to ensure safe operation of the wind tunnel at high wind speeds.

[0039] The vibration damping hole cover plate screw 11 is a type of anti-loosening screw that permanently connects the vibration damping hole cover plate 6 and the vibration damping hole 18 through an embedded connection, ensuring the safe operation of the wind tunnel at high wind speeds.

[0040] Lock nut 12 is a type of anti-loosening nut. During installation, lock nut 12 is placed outside the cavity of the combined vibration damping device.

[0041] Locking nut 213 is a type of anti-loosening nut. During installation, locking nut 213 is positioned outside the cavity of the combined vibration damping device.

[0042] The damping hole cover plate screw pad 14 is a thick rectangular pad, which can improve the connection safety of the damping hole cover plate 1 5 and the damping hole cover plate 2 6. During installation, the locking nut 1 12 and the locking nut 2 13 are placed outside the cavity of the combined damping device.

[0043] The support segment ring stiffener 15 is a ring stiffener. The support segment ring stiffener 15 and the support segment 3 are welded together in a ring shape to improve the vibration resistance and overall rigidity of the support segment 3.

[0044] The annular rubber gasket 16 is an annular washer with 24 through holes, used for sealing the connection between the support section 3 and the vibration damping ring 2. It can buffer and balance the pulsating pressure difference inside and outside the tunnel wall of the first diffusion section.

[0045] Vibration damping holes 17 are located on the vibration damping ring 2. They are square through holes arranged in a circular pattern. Their length and width are 1 / 10 of the diameter of the vibration damping ring. There are 18 such holes.

[0046] Vibration damping holes 2 (18 in total) are located on vibration damping ring 2. They are rectangular through holes arranged in a circular pattern. Their aspect ratio is 1.2, and their length is 1 / 14 of the diameter of the vibration damping ring. There are 18 such holes.

[0047] Flange 2 19, Flange 3 20, and Flange 4 21 are all common flange structure connectors, each with 24 holes for connection with support section 3, airflow collector 1 vibration damping ring 2, and the first diffuser section of the cavity.

[0048] An annular rubber pad 16 is installed between the airflow collector 1, the support section 3, and the flanges 1-7, 2-19, 3-20, and 4-21. It is connected through the connection holes to complete the soft connection of several components of the vibration damping device. It plays a buffering role against the pulsating pressure difference acting on the inside and outside of the diffuser section, thereby weakening the structural vibration caused by the impact of the free jet detachment vortex on the closed part of the tunnel.

[0049] The horn-shaped reinforcing ribs 22 are arranged circumferentially on the outer surface of the airflow collector 1. They are welded to the outer surface of the airflow collector 1. This improves the airflow collection efficiency and overall structural strength of the airflow collector 1 under high blockage ratio conditions. The horn-shaped reinforcing ribs 22 are arc-shaped reinforcing ribs, and their external dimensions are fitted using coordinate points of a quintic function. The horn-shaped reinforcing ribs 22 are welded to the return flow component of the airflow collector 1 according to their circumferential distribution.

[0050] exist Figure 1 In the process, following the airflow direction and using the conventional aerodynamic layout and connection method of the parachute test wind tunnel, the combined vibration damping device is placed in the recirculation section of the parachute test wind tunnel. The device is then installed according to the required installation accuracy using positioning bolts and relevant standard fasteners. Figure 2 and Figure 3 The overall structure of the combined vibration damping device is shown separately.

[0051] The structural diagram of the present invention is shown below. Figure 4 , Figure 5 and Figure 6 The vibration damping ring 2 is provided with 18 vibration damping holes, namely, damping hole 17 and damping hole 18. The spacing of damping hole 17 is one-twenty-third of the circumference of vibration damping ring 2, and the spacing of damping hole 18 is one-sixteenth of the circumference of vibration damping ring 2. A damping hole cover plate 5 is placed over the damping hole 17 in the vibration damping ring 2, alternating between two holes. The damping hole cover plate 5 is then fastened to the damping hole 17 in the vibration damping ring 2 using damping hole cover plate screws 10, locking nuts 12, and damping hole cover screw washers 14, alternating between two holes. Cover the vibration damping hole 18 in the vibration damping ring 2 with the vibration damping hole cover plate 2 6, and install it on the vibration damping hole 18 every other hole. Secure the vibration damping hole cover plate 2 6 to the vibration damping hole 18 in the vibration damping ring 2 by the vibration damping hole cover plate screw 2 11, the locking nut 2 13, and the vibration damping hole cover screw washer 14. Weld the rectangular vibration damping ring reinforcing frame 1 8 and the rectangular vibration damping ring reinforcing frame 2 (9) to the vibration damping hole 1 17 and the vibration damping hole 18, respectively. Install the annular rubber pads into the airflow collector 1, the vibration damping ring 2, the support section 3, the flange 1, the flange 2, the flange 3, and the flange 4, and secure them with standard fastening bolts. After the connection is completed, weld the support 4 to the support section 3 in an arc, and connect the support leg of the support 4 to the equipment base of the test hall with anchor bolts. Continue until the combined vibration damping device of the present invention is installed in the tunnel system of the parachute test wind tunnel.

[0052] Example

[0053] In the initial state of the wind tunnel, the horn-shaped component in the airflow collector adopted a fifth-order internal surface. With the damping holes fully open, the vibrations were as follows: low-frequency flutter occurred at approximately 45 m / s and 65 m / s, the vibration amplitude of the diffuser section reached a certain level, and vibration was normal at other wind speeds. Theoretical calculations indicate that the airflow excitation frequency at this time is between 18 Hz and 25 Hz, with the main flutter peak occurring around 20 Hz. At this point, the open area was approximately 45% of the test section's cross-sectional area. After sealing the damping holes in different numbers and locations, the open area became approximately 22% of the test section's cross-sectional area.

[0054] After adjusting the position and number of vibration damping holes, the vibration at the collector was measured at wind speeds of 10–80 m / s. The results showed that the wind speed point where flutter occurred shifted to around 50 m / s. By adjusting the vibration frequency generated by the jet excitation in the wind tunnel test section, the resonance phenomenon at the wind speed point was moved to below 30 m / s and around 90 m / s, successfully avoiding the commonly used wind speed points in the wind tunnel.

[0055] The above technical solutions are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent changes made in accordance with the scope of this application shall still fall within the protection scope of this application.

Claims

1. A combined vibration damping device for a parachute test wind tunnel, comprising an airflow collector (1), a vibration damping ring (2), a support section (3), a vibration damping hole cover plate one (5), a vibration damping hole cover plate two (6), a flange one (7), an annular rubber pad (16), a vibration damping hole one (17), a vibration damping hole two (18), a flange three (20), and a flange four (21), characterized in that, The airflow collector (1) is a tubular structure with a flared return port at the front. Flange 4 (21), vibration damping ring (2), flange 3 (20), annular rubber gasket (16), flange 1 (7), and flange 2 (19) are axially provided with connecting through holes. Flange 4 (21) is connected in sequence. The vibration damping ring (2), flange two (19), support section (3), flange three (20), annular rubber pad (16), flange one (7) are coaxially and concentrically fixedly connected with the airflow collector (1). The vibration damping ring (2) is provided with multiple vibration damping holes one (17) and vibration damping holes two (18) distributed in a left-right matrix. Vibration damping holes one (17) and vibration damping holes two (18) are respectively provided with vibration damping hole cover plate one (5) and vibration damping hole cover plate two (6) covering part of their quantity. Annular rubber pads are provided between the airflow collector (1) and support section (3), between support section (3) and vibration damping ring (2), between flange one (7) and flange three (20), and between flange two (19) and flange four (21). They are fastened together using standard fastening bolts. There are eighteen vibration damping holes one (17) and eighteen vibration damping holes two (18). The spacing of vibration damping holes one (17) is one-twenty-third of the circumference of the vibration damping ring (2), and the spacing of vibration damping holes two (18) is one-sixteenth of the circumference of the vibration damping ring (2). Vibration damping hole cover plate one (5) is fixed on vibration damping hole one (17) at intervals. The vibration damping device also includes vibration damping hole cover plate screws and locking nuts and vibration damping hole cover screw pads. The vibration damping hole cover plate covers the vibration damping hole and is fastened by the vibration damping hole cover plate screws and locking nuts and vibration damping hole cover screw pads. The area of ​​a single damping hole one (17) is 1 / 50 of the nozzle area of ​​the test section, and the area of ​​a single damping hole two (18) is 7 / 100 of the nozzle area of ​​the test section. The front and rear parts of the damping ring (2) are respectively provided with a flange two (19). The front and rear flange two (19) are respectively provided with two positioning through holes. The two positioning through holes are distributed vertically. One positioning through hole is at 15° with the center normal of the damping ring (2), and the other positioning hole is at 165° with the center normal of the damping ring (2). The front flange two (19) of the damping ring (2) is provided with twenty-four through holes for connecting with the original first diffusion section of the wind tunnel, and the rear flange two (19) is provided with eighteen through holes for connecting with the front flange three (20) of the support section (3).

2. The combined vibration damping device for a parachute test wind tunnel according to claim 1, characterized in that, The flange 1 (7) is provided with two positioning through holes and twenty-four connection through holes for connecting with the damping ring (2). The two positioning through holes are distributed vertically. One positioning through hole is at 15° with the center normal of the airflow collector (1), and the other positioning through hole is at 165° with the center normal of the airflow collector (1).

3. The combined vibration damping device for a parachute test wind tunnel according to claim 1, characterized in that, The vibration damping device also includes a rectangular vibration damping ring reinforcement frame one (8) and a rectangular vibration damping ring reinforcement frame two (9), which are welded to vibration damping hole one (17) and vibration damping hole two (18) respectively.

4. The combined vibration damping device for a parachute test wind tunnel according to claim 1, characterized in that, The vibration damping device also includes a support (4), which is an I-shaped semi-circular support. The upper end of the support section (3) and the lower semi-circular arc are welded together by the support section ring reinforcing rib (15). The two support legs are connected to the support foundation of the wind tunnel test hall by anchor bolts.

5. The combined vibration damping device for a parachute test wind tunnel according to claim 1, characterized in that, The vibration damping device also includes a horn-shaped reinforcing rib (22), which is arranged circumferentially on the outer surface of the airflow collector (1) and welded to the outer surface of the airflow collector (1).

6. The combined vibration damping device for a parachute test wind tunnel according to claim 1, characterized in that, The vibration damping device also includes a support section ring reinforcing rib (15), which is a ring reinforcing rib and is ring welded to the support section (3).

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