A jet test device for wind tunnel model

Abstract

The present invention relates to the technical field of aircraft aerodynamic test, and discloses a jet test device for a wind tunnel model, including a rocket body model with a cavity inside; a plurality of high-speed nozzles are arranged at the tail of the rocket body model, a high-pressure gas source is arranged outside the rocket body model, a plurality of air intake hoses are connected to the high-pressure gas source, and the inlet end of the high-speed nozzle is connected to the air intake hose through a deflector; a support rod is coaxially fixed to the rocket body model, one end of the support rod extends out of the rocket body model and is connected to an attitude control mechanism in the wind tunnel, and a rod-type strain balance is installed at the other end. The present invention simulates the external flow field of arrows in a wind tunnel, simulates the power source by using a high-pressure gas source, simulates the exhaust effect of a reverse thrust engine by using a built-in pipeline and a high-speed nozzle of the rocket body model, simulates the motion posture of the arrow by using the rocket body model and the wind tunnel attitude control mechanism, obtains the overall aerodynamic force and torque of the rocket body model by using a rod-type strain balance, and simulates the return process of the first stage of the rocket as realistically as possible to obtain valuable aerodynamic data.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft aerodynamic testing, and in particular to a jet flow testing device for a wind tunnel model. Background Art

[0002] Most rockets are disposable products. In the process of launching space devices into space, the fuel inside the rocket is almost completely consumed, and the rocket shell and rocket engine fall and smash on the ground in an uncontrolled state. As we all know, the cost of rocket fuel only accounts for a small part of the overall cost of the rocket, while the rocket shell and rocket engine smashed after the rocket is launched are extremely expensive. Taking practical engineering and technical means to recover the rocket shell and rocket engine will bring greater economic value.

[0003] There are three main ways to recover space devices such as rockets from high altitudes: gliding landing recovery, parachute recovery, and vertical recovery using a reverse thrust engine. The present invention is mainly used to simulate the vertical recovery rocket performance test device of the rocket when the reverse thrust engine is ignited to generate reverse thrust, the control surface changes angle to control the rocket attitude, and the landing legs are folded and unfolded. This recovery method can be used for the first stage recovery of the rocket. It can make the rocket land at a designated recovery location at a suitable angle, a gradually reduced recovery speed, and a planned recovery path under human control; at the same time, the reverse thrust vertical recovery of the rocket has very high requirements for engineering technology. It not only requires the reverse thrust engine to provide sufficient deceleration capacity to make the rocket very slow when approaching the ground, but also requires the operating rudder on the rocket to have good operating performance for the rocket to ensure the recovery trajectory and recovery landing point of the rocket at high altitude and high speed. Summary of the invention

[0004] Based on the above problems, the present invention provides a jet test device for a wind tunnel model, which simulates the external flow field of an arrow in a wind tunnel, simulates the power source of a thrust reverser engine by a high-pressure air source, adjusts the airflow rate and thrust by a flow regulating valve, simulates the exhaust effect of the thrust reverser engine by built-in pipelines and high-speed nozzles in a rocket body model, simulates the movement posture of the arrow by a rocket body model and a wind tunnel attitude control mechanism, obtains the overall aerodynamic force and torque of the rocket body model by a rod-type strain balance, and simulates the return process of the first stage of the rocket as realistically as possible to obtain valuable aerodynamic data.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A jet test device for a wind tunnel model comprises a rocket body model arranged in the wind tunnel, wherein an axial cavity is arranged in the rocket body model; a plurality of high-speed nozzles for ejecting reverse airflow are evenly arranged at the tail of the rocket body model, a high-pressure gas source is also arranged in the rocket body model, a plurality of air intake hoses are connected to the high-pressure gas source, the inlet ends of the high-speed nozzles are connected to the air intake hoses through a flow guide, and a flow regulating valve is arranged on each air intake hose; a support rod is coaxially fixed to the rocket body model, one end of the support rod extends out of the rocket body model and is connected to an attitude control mechanism in the wind tunnel, and a rod-type strain balance is coaxially fixedly installed on the other end of the support rod.

[0007] Furthermore, a constriction section is arranged near the outlet end of the high-speed nozzle, and a conical expansion outlet with a gradually increasing diameter is connected to the far end of the constriction section.

[0008] Furthermore, a pressure measuring rake composed of a plurality of pressure measuring tubes is arranged in the high-speed nozzle, and the pressure measuring tubes on the pressure measuring rake are arranged in a straight line along the axis of the high-speed nozzle.

[0009] Furthermore, at least two grid rudders are arranged on the outer wall of the rocket body model, and the grid rudders are evenly distributed circumferentially along the outer wall of the rocket body model.

[0010] Furthermore, the deflector includes a fixed block, a cylindrical groove that can be sleeved on the support rod is provided in the middle of the fixed block, and a plurality of ventilation pipes parallel to the axial direction are provided on the side wall of the fixed block; one end of the ventilation pipe is connected to the air intake hose, and the other end of the ventilation pipe is connected to the air intake end of the high-speed nozzle through a ventilation steel pipe.

[0011] Furthermore, the number of the air intake hoses and the number of the high-speed nozzles are four, and the ventilation steel pipes connecting the four high-speed nozzles are evenly distributed in the cavity of the rocket body model through a fixed bracket.

[0012] Furthermore, there are four air intake hoses and three high-speed nozzles, one of which is coaxially arranged with the rocket body model, and the other two are circumferentially distributed along the central axis of the rocket body model; the high-speed nozzle located on the central axis of the rocket body model is connected to two ventilation steel pipes connected with air intake hoses through a Y-shaped manifold.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1) The present invention can simulate the aerodynamic performance of the rocket's reverse thrust engine with and without ignition, simulate the effect of ignition on rocket deceleration under different engine position layouts, simulate the effect of the reverse thrust engine on rocket deceleration under different thrust states, and simulate the effect of the rocket's operating control surfaces at different angles on the overall aerodynamic characteristics of the rocket; at the same time, in conjunction with experiments conducted in a suitable wind tunnel, it can simulate and test the aerodynamic performance of the rocket at different return speeds from high altitude to close to the ground.

[0015] 2) When designing the jet device of the present invention, the flow characteristics of the airflow inside and outside the wind tunnel test, the stiffness and strength of the components, the pressure control and sealing of the high-pressure airflow, the accuracy and reliability of the device under complex airflow, various test data acquisition methods, the processing technology and production cost of the device were comprehensively considered. The jet device has good engineering practical value.

[0016] 3) The jet test device of the present invention can enable arrow models to carry out comprehensive tests in a wind tunnel. The jet device can simulate the working state of a rocket reverse thrust engine with a relatively high drop pressure, can control the thrust size through a pressure regulating valve, and can quickly feedback the jet pressure through a built-in pressure measuring rake;

[0017] 4) The test data obtained by the jet device of the present invention can guide the fuel configuration, rocket body deceleration, rocket body attitude control and optimization of the rocket's own structural strength during the return and recovery of a real rocket, with obvious benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the jet test device for the arrow wind tunnel model in Example 1 or 2;

[0019] Figure 2 is a cross-sectional view of the jet test device in Example 1 or 2 in the rocket body model;

[0020] Figure 3 Schematic diagram of the structure of the high-speed nozzle in Example 1 or 2;

[0021] Figure 4 is a schematic structural diagram of the flow director in Example 1 or 2;

[0022] Figure 5 It is a schematic diagram of the structure of the support rod in Example 1 or 2;

[0023] Figure 6 It is a structural schematic diagram of the rod-type strain balance in Example 1 or 2;

[0024] Figure 7 It is a structural schematic diagram of the pressure measuring rake in Example 1 or 2;

[0025] Figure 8 Schematic diagram of the structure of the rocket body model with the jet test device in Example 1;

[0026] Fig. 9 is a schematic diagram of the structure of the fixing bracket in Example 1 or 2;

[0027] Fig.10 Schematic diagram of the structure of the rocket body model with the jet test device in Example 2;

[0028] Fig.11 Schematic diagram of the structure of the Y-shaped manifold in Example 2;

[0029] Fig.12 A schematic diagram of the structure of the small hinge torque balance for obtaining the operating control surface in Example 1;

[0030] Among them, 1. Rocket body model; 2. High-speed nozzle; 3. High-pressure gas source; 4. Inlet hose; 5. Flow regulating valve; 6. Support rod; 7. Rod-type strain balance; 8. Reduction section; 9. Conical expansion outlet; 10. Pressure measuring rake; 11. Grid rudder; 12. Fixed block; 13. Fixed bracket; 14. Ventilation steel pipe; 15. Y-shaped manifold; 16. Small hinge torque balance. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The schematic implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0032] Embodiment 1:

[0033] See also Figure 1-9 as well as Fig.12 A jet test device for a wind tunnel model comprises a rocket model 1 arranged in the wind tunnel, wherein the rocket model 1 is provided with an axial cavity; a plurality of high-speed nozzles 2 for ejecting reverse airflow are evenly arranged at the tail of the rocket model 1, a high-pressure gas source 3 is also arranged in the rocket model 1, a plurality of air intake hoses 4 are connected to the high-pressure gas source 3, the inlet end of the high-speed nozzle 2 is connected to the air intake hose 4 through a guide, and a flow regulating valve 5 is arranged on each air intake hose 4; a support rod 6 is coaxially fixed to the rocket model 1, one end of the support rod 6 extends out of the rocket model 1 and is connected to the attitude control mechanism in the wind tunnel, and a rod-type strain balance 7 is coaxially fixedly installed on the other end of the support rod 6.

[0034] In the present embodiment, the support rod 6 is connected to the wind tunnel attitude control mechanism, so that the pitch, roll and sideslip attitude of the rocket are simulated by the wind tunnel attitude control mechanism. In the process of simulating attitude, the thrust state of the rocket reverse thrust engine is simulated at the high-speed nozzle 2 by the mode driven by the high-pressure gas source 3, so that the wind tunnel can be tested under the subsonic, transonic and supersonic airflow conditions, and the aerodynamic data of the rocket as a whole is obtained by the rod-type strain balance 7. In the present embodiment, the external flow field of arrows is simulated in the wind tunnel, the power source of the reverse thrust engine is simulated by the high-pressure gas source 3, the airflow flow rate and the thrust size are adjusted by the flow regulating valve 5, the exhaust effect of the reverse thrust engine is simulated by the built-in pipeline of the rocket body model 1 and the high-speed nozzle 2, the motion attitude of arrows is simulated by the rocket body model 1 and the wind tunnel attitude control mechanism, the overall aerodynamic force and torque of the rocket body model 1 are obtained by the rod-type strain balance 7, and the return process of the first stage of the rocket is simulated as realistically as possible to obtain valuable aerodynamic data.

[0035] The high-speed nozzle 2 is provided with a conical expansion outlet 9 with a gradually increasing caliber at the distal end of the conical expansion outlet 8. The high-speed nozzle 2 in this embodiment must be specially designed, and it must take into account two aspects: first, the interior of the high-speed nozzle 2 is a Laval high-speed nozzle 2 type (the internal cross-section of the high-speed nozzle 2 is first contracted and then expanded), and the expansion outlet of the high-speed nozzle 2 is conical to ensure that the outlet airflow of the high-speed nozzle 2 is consistent with the airflow of the real rocket reverse thrust engine, which is a supersonic airflow; second, the design of the internal flow pipeline and the high-speed nozzle 2 must have sufficient pressure bearing capacity and rigidity.

[0036] In order to obtain the pressure of the high-speed nozzle 2 to ensure the jet effect, a pressure measuring rake 10 composed of multiple pressure measuring tubes is arranged in the high-speed nozzle 2, and the pressure measuring tubes on the pressure measuring rake 10 are arranged in a straight line on the high-speed nozzle 2 along the axis of the high-speed nozzle 2. The built-in straight-line pressure measuring rake 10 specially designed inside the high-speed nozzle 2 is formed to monitor the air pressure in the high-speed nozzle 2 in real time, which is convenient for guiding the adjustment of the flow control valve 5, so that the jet process forms a control closed loop, ensuring the accuracy and reliability of the reverse thrust jet simulation process.

[0037] At least two grid rudders 11 are arranged on the outer wall of the rocket body model 1, and the grid rudders 11 are evenly distributed along the outer wall of the rocket body model 1. The data of the operating rudder surface is obtained through a small hinge moment balance 16, and the aerodynamic image of the reverse thrust engine jet interacting with the external high-speed airflow under working conditions is obtained through schlieren and high-speed photography, providing data support for the design of key performances in the rocket return.

[0038] The deflector includes a fixed block 12, the middle of which is provided with a cylindrical groove that can be sleeved on the support rod 6, and the side wall of the fixed block 12 is provided with a plurality of ventilation pipes parallel to the axial direction; one end of the ventilation pipe is connected to the air intake hose 4, and the other end of the ventilation pipe is connected to the air intake end of the high-speed nozzle 2 through the ventilation steel pipe 14. There are four air intake hoses 4 and four high-speed nozzles 2, and the ventilation steel pipes 14 connecting the four high-speed nozzles 2 are evenly distributed in the cavity of the rocket body model 1 through the fixed bracket 13. Four reverse thrust engine jets can be simulated at the same time, and each jet ventilation pipe is independently controlled by the flow regulating valve 5; in the wind tunnel test, it can be selected whether to start the jet device or start one or more of the high-speed nozzles 2 as needed, and the intake pressure can also be controlled by the flow regulating valve 5 to change the pressure of the jet outlet. The high-speed nozzle 2 is an independent component and can be quickly replaced in the wind tunnel test. The internal profile of the high-speed nozzle 2 of different specifications can be designed separately according to the simulation of different engines to simulate the reverse thrust effect more realistically. The fixing bracket 13 selected in this embodiment includes a rod and clamping grooves arranged at both ends of the rod. The two ventilation steel pipes 14 are clamped by the clamping grooves at both ends respectively, so that the ventilation steel pipes 14 are supported and fixed.

[0039] In addition, the internal cavity of the rocket body model 1 in this embodiment is narrow and a gap must be left between it and the high-speed nozzle 2. At the same time, the entire jet test device runs through the front and back of the model, so that the size of the jet pipe and the high-speed nozzle 2 is obviously limited. Under such working conditions, it is necessary to ensure that the ventilation pipeline and the high-speed nozzle 2 do not leak when working at the highest pressure. In the present invention, it is required that the material of the ventilation pipeline is metal and the wall thickness is not less than 3mm. In addition, conical sealing, cylindrical positioning, and fine thread pre-tightening are used between the main airflow links such as the intake hose 4, the deflector, the ventilation steel pipe 14, and the high-speed nozzle 2 to ensure the air tightness of the device; and for the rigidity of the ventilation pipeline, the main measures adopted are to strengthen the deflector structure, control the deformation of the internal pipeline of the model itself, and add a fixed bracket 13.

[0040] The material selection and manufacturing process of the main components in this embodiment are as follows:

[0041] ① Inlet soft channel - use a high-pressure rubber hose with a metal mesh inside and a pressure of not less than 15Mpa to facilitate the arrangement and sealing connection of long pipelines;

[0042] ② Deflector - Rockets are generally slender in shape, and the jet device needs to take in air from the rear, so that the entire jet device has a typical cantilever structure. The inside of the deflector is connected to the cylindrical support rod 6 through a cylindrical surface. The outer ring of the deflector is designed with multiple ventilation pipes. The deflector itself should have sufficient stability, so the deflector should be made of high-strength alloy steel material, adopt an integrated design and overall CNC milling, deep hole drilling and other processing processes;

[0043] ③ Ventilation steel pipe 14——High-strength alloy steel material, using CNC lathe, deep hole drilling, pipe bending and other processes;

[0044] ④ High-speed nozzle 2——Made of high-strength alloy steel, using CNC lathe, deep hole drilling, electric spark and other processes;

[0045] ⑤Support rod 6——needs to bear all the aerodynamic loads of the rocket model and the reverse thrust of the jet device. It is made of 00Ni18Co8Mo5TiAl material and adopts solid solution aging treatment, CNC turning, deep hole drilling, CNC milling and other manufacturing processes.

[0046] Embodiment 2:

[0047] See also Figure 1-7 and Figure 9-11A jet test device for a wind tunnel model comprises a rocket model 1 arranged in the wind tunnel, wherein the rocket model 1 is provided with an axial cavity; a plurality of high-speed nozzles 2 for ejecting reverse airflow are evenly arranged at the tail of the rocket model 1, a high-pressure gas source 3 is also arranged outside the rocket model 1, a plurality of air intake hoses 4 are connected to the high-pressure gas source 3, the inlet end of the high-speed nozzle 2 is connected to the air intake hose 4 through a guide, and a flow regulating valve 5 is arranged on each air intake hose 4; a support rod 6 is coaxially fixed to the rocket model 1, one end of the support rod 6 extends out of the rocket model 1 and is connected to the attitude control mechanism in the wind tunnel, and a rod-type strain balance 7 is coaxially fixedly installed on the other end of the support rod 6.

[0048] The deflector includes a fixed block 12, the middle of which is provided with a cylindrical groove that can be sleeved on the support rod 6, and the side wall of the fixed block 12 is provided with a plurality of ventilation pipes parallel to the axial direction; one end of the ventilation pipe is connected with the air intake hose 4, and the other end of the ventilation pipe is connected with the air intake end of the high-speed nozzle 2 through the ventilation steel pipe 14. There are four air intake hoses 4 and three high-speed nozzles 2, one of which is coaxially arranged with the rocket body model 1, and the other two high-speed nozzles 2 are distributed circumferentially along the central axis of the rocket body model 1; the high-speed nozzle 2 located at the central axis of the rocket body model 1 is connected with two ventilation steel pipes 14 connected with the air intake hose 4 through the Y-shaped manifold 15.

[0049] In this embodiment, by setting one of the high-speed nozzles 2 at the center axis of the rocket body, it is possible to simulate the operation of only one thrust engine located on the center axis, so as to obtain corresponding aerodynamic test data.

[0050] The other parts of this embodiment are the same as those of Embodiment 1 and will not be described again here.

[0051] The above is an embodiment of the present invention. The above embodiments and the specific parameters in the embodiments are only for the purpose of clearly describing the invention verification process, and are not intended to limit the patent protection scope of the present invention. The patent protection scope of the present invention is still subject to its claims. Any equivalent structural changes made by using the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims

1. A jet flow test device for a wind tunnel model, characterized in that: The invention comprises a rocket body model (1) arranged in a wind tunnel, wherein the rocket body model (1) is provided with a cavity along the axial direction; a plurality of high-speed nozzles (2) for ejecting reverse airflow are evenly arranged at the tail of the rocket body model (1); the high-speed nozzles (2) are independent components and can be quickly replaced in a wind tunnel test; the internal profiles of the high-speed nozzles (2) of different specifications can be individually designed according to the simulation of different engines, so as to simulate the reverse thrust effect more realistically; a high-pressure gas source (3) is also arranged in the rocket body model (1); a plurality of air intake hoses (4) are connected to the high-pressure gas source (3); the inlet end of the high-speed nozzle (2) is connected to the air intake hose (4) through a flow guide, and each of the air intake hoses (4) is provided with a flow regulating valve (5); a support rod (6) is coaxially fixed to the rocket body model (1); one end of the support rod (6) extends out of the rocket body model (1) and is connected to an attitude control mechanism in the wind tunnel; the other end of the support rod (6) is coaxially fixedly installed with a rod-type strain balance (7); The high-speed nozzle (2) is provided with a constricted section (8) near the outlet end, and the distal end of the constricted section (8) is connected to a conical expansion outlet (9) with a gradually increasing caliber; A pressure measuring rake (10) composed of a plurality of pressure measuring tubes is arranged in the high-speed nozzle (2), and the pressure measuring tubes on the pressure measuring rake (10) are arranged in a straight line along the axis of the high-speed nozzle (2) on the high-speed nozzle (2); The outer wall of the rocket body model (1) is provided with at least two grid rudders (11), and the grid rudders (11) are evenly distributed along the outer wall of the rocket body model (1) in a circumferential direction, and data of operating the rudder surfaces is obtained through a small hinge moment balance (16).

2. A jet flow test device for a wind tunnel model according to claim 1, characterized in that: The deflector comprises a fixed block (12), the middle part of which is provided with a cylindrical groove which can be sleeved on the support rod (6), and the side wall of the fixed block (12) is provided with a plurality of ventilation pipes parallel to the axial direction; one end of the ventilation pipe is connected to the air intake hose (4), and the other end of the ventilation pipe is connected to the air intake end of the high-speed nozzle (2) through a ventilation steel pipe (14).

3. A jet flow test device for a wind tunnel model according to claim 2, characterized in that: The number of the air intake hose (4) and the number of the high-speed nozzles (2) are both four, and the ventilation steel pipes (14) connecting the four high-speed nozzles (2) are evenly distributed in the cavity of the rocket body model (1) through a fixed bracket (13).

4. A jet flow test device for a wind tunnel model according to claim 2, characterized in that: The number of the air intake hoses (4) is four, the number of the high-speed nozzles (2) is three, one of the high-speed nozzles (2) is coaxially arranged with the rocket body model (1), and the other two high-speed nozzles (2) are circumferentially distributed along the central axis of the rocket body model (1); the high-speed nozzle (2) located on the central axis of the rocket body model (1) is connected to two ventilation steel pipes (14) connected to the air intake hoses (4) through a Y-shaped manifold (15).

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