Reverse jet flow system structure for wind tunnel test

Abstract

The utility model discloses a reverse jet flow system structure for a wind tunnel test. The reverse jet flow system structure comprises a tail jet pipe, a gas collection chamber, a pull rod, a high-pressure pipeline, a ventilation support rod and a force measurement balance. The reverse jet flow system is fixedly connected with a wind tunnel through a supporting rod, a gas collection chamber is connected with a ventilation supporting rod through a pull rod and a high-pressure pipeline, a balance is connected with the ventilation supporting rod through cone matching, and finally a tail jet pipe and a test model are installed to achieve installation and reverse jet flow of the model in the wind tunnel. According to the utility model, the balance is arranged on one side of the ventilation support rod in an offset manner, and the jet flow gas collection chamber is moved forwards, so that the axial force of the test model is measured while the reverse jet flow is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of wind tunnel tests, in particular to a reverse jet full-model force measurement test jet system structure. Background Art

[0002] Jet streams are typically generated by micro-pulse engines, ignition generators, or main engine induced flow, generating direct force and providing direct control force and torque. They offer the advantages of high-precision, fast-response control at low altitudes and speeds, and in rarefied airflow at high altitudes. Jet streams are categorized by direction: tail forward jet, side jet, and head reverse jet.

[0003] Despite the numerous advantages of jet control, the complex structure of the jet interference flow field makes it difficult to accurately predict the direct and interfering jet forces. Current research on jet flow fields and interference utilizes numerical simulations, flight tests, and wind tunnel tests. Numerical simulations are suitable for studying flow mechanisms. Flight tests are suitable for comprehensive evaluation. Wind tunnel tests allow for direct observations but cannot simulate all similar parameters. Research on jets primarily relies on a combination of these methods.

[0004] Reverse head jet flow is commonly used in rocket recovery and rearward launch vehicles. In this state, the focus is on the axial force CA acting on the vehicle. For wind tunnel tests of this type of reverse jet flow, most current test systems can only measure five components of the vehicle and interfering flow field, in addition to the axial force CA. Therefore, current reverse head jet flow tests are difficult to meet mission requirements. Utility Model Content

[0005] The technical problem solved by the utility model is: to overcome the shortcomings of the existing technology, to provide a wind tunnel test reverse jet system structure, to make the existing force measuring balance coaxial with the ventilation support rod, and the ventilation pipeline reaches the air collecting chamber and the tail nozzle through the balance axis inside the balance, and instead to bias the force measuring balance on one side of the ventilation support rod, and connect it to the air collecting chamber and the tail nozzle through a high-pressure pipeline separately, thereby overcoming the deficiency of the original scheme that it cannot measure the axial force CA of the model.

[0006] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0007] A reverse jet system structure for a wind tunnel test, comprising: a tail nozzle, a gas collecting chamber, a tie rod, a high-pressure pipeline, a ventilation support rod and a force balance;

[0008] The outer wall of the tail end of the ventilation strut is fixedly connected to the wind tunnel angle of attack mechanism, and the tail end of the ventilation strut is used to receive the high-pressure gas source input by the high-pressure pipeline;

[0009] One end of the force balance is fixedly connected to the front end surface of the ventilation support rod, and the other end of the force balance is connected to the test model;

[0010] Both ends of the high-pressure pipeline are connected to the gas collecting chamber and the ventilation support rod respectively;

[0011] The two ends of the pull rod are fixedly connected to the gas collecting chamber and the ventilation support rod respectively;

[0012] The tail nozzle is fixed on the front end of the air collecting chamber and serves as the outlet of the air collecting chamber.

[0013] Preferably, both ends of the force balance are processed with truncated cone structures, which are used for fixed connection with the ventilation support rod and the test model respectively.

[0014] Preferably, the axis of the high-pressure pipeline does not coincide with the axis of the ventilation strut, and the axis of the high-pressure pipeline coincides with the axis of the gas collecting chamber and the tail nozzle;

[0015] The axis of the force balance and the ventilation strut do not coincide.

[0016] Preferably, the pull rod is made of steel with a grade of F141.

[0017] Preferably, it also includes: a pressure measuring point;

[0018] The pressure measuring point is set at the tail end of the ventilation support rod, and the pressure measuring point measures the jet pressure through a high-pressure sensor.

[0019] Preferably, the gas collecting chamber is designed as a three-section structure which is processed separately and finally welded into a whole;

[0020] The inner diameter of the middle section of the gas collecting chamber is larger than the inner diameter of the high-pressure pipeline;

[0021] The front end of the pull rod passes through the three-section structure of the air collecting chamber and tightens and fixes the three-section structure of the air collecting chamber.

[0022] Preferably, a certain gap is maintained between the test model and the tail nozzle, the gas collecting chamber, the pull rod, the high-pressure pipeline, and the ventilation support rod, and the gap value range is 2.5 to 3 mm.

[0023] Preferably, the rear end of the high-pressure pipeline is threadedly engaged with the ventilation support rod, and the front end of the high-pressure pipeline is cylindrically plugged into the gas collecting chamber.

[0024] Preferably, the high-pressure pipeline and the ventilation support rod, and the high-pressure pipeline and the gas collecting chamber are sealed by using copper gaskets and sealing glue.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) The utility model offsets the force balance and designs a separate high-pressure pipeline. The direct force of the jet is transmitted to the ventilation support rod through the pull rod and the high-pressure pipeline, and no longer passes through the force balance. Therefore, the force balance can directly measure the axial force CA of the test model.

[0027] 2) Since the direct force of the jet does not pass through the force measuring balance, there is no need to design a new weight balance, and the existing weight series balance can be used.

[0028] 3) After the high-pressure pipeline is designed separately, the jet airflow rate can be larger, and the jet state of the tail nozzle 1 with a larger throat diameter can be simulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Axonometric view of the reverse jet system designed for the present invention.

[0030] Figure 2(a) is a schematic diagram of the reverse jet tail nozzle structure.

[0031] Figure 2(b) is a cross-sectional view of the jet tail nozzle

[0032] Figure 3(a) is a schematic diagram of the gas collecting chamber structure.

[0033] Figure 3(b) is a cross-sectional view of the gas collecting chamber.

[0034] Figure 3(c) is a cross-sectional view of the gas collecting chamber.

[0035] Figure 4(a) is a schematic diagram of the pull rod structure.

[0036] Figure 4(b) is a cross-sectional view of the tie rod.

[0037] Figure 5(a) is a schematic diagram of the high-pressure pipeline structure.

[0038] Figure 5(b) is a cross-sectional view of the high-pressure pipeline.

[0039] Figure 6(a) is a schematic diagram of the force balance structure for wind tunnel testing.

[0040] Figure 6(b) is a cross-sectional view of the force balance in the wind tunnel test.

[0041] Figure 7(a) is a schematic diagram of the ventilation rod structure.

[0042] Figure 7(b) is a cross-sectional view of the ventilation strut.

[0043] Figure 8 This is a schematic structural diagram of the reverse jet system designed for the present utility model. DETAILED DESCRIPTION

[0044] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments:

[0045] like Figure 1 and Figure 8As shown in the figure, the present invention provides a reverse jet system structure for wind tunnel testing, comprising: a tail nozzle 1, a plenum 2, a tie rod 3, a high-pressure pipeline 4, a ventilation strut 5, a pressure measuring point 6, and a force balance 7. The outer wall of the rear end of the ventilation strut 5 is fixedly connected to the wind tunnel angle of attack mechanism, and the rear end of the ventilation strut 5 is used to receive a high-pressure gas source input by the high-pressure pipeline.

[0046] One end of the force balance 7 is connected to the ventilation rod 5, and the other end is connected to the test model. As shown in Figures 6(a) and 6(b), the force balance 7 has a truncated cone structure at each end, which is used to securely connect to the ventilation rod 5 and the test model. The ventilation rod 5 and the force balance 7 are connected by a conical plug-in connection.

[0047] The two ends of the high-pressure pipeline 4 are connected to the gas collecting chamber 2 and the ventilation strut 5 respectively, and the ventilation strut 5 outputs high-pressure gas to the high-pressure pipeline 4 through the high-pressure pipeline 4. The structure of the ventilation strut 5 is shown in Figure 7 (a) (b).

[0048] The tail nozzle 1, the gas collecting chamber 2 and the high-pressure pipeline 4 are connected in sequence.

[0049] like Figure 8 As shown, the axis of the high-pressure pipeline 4 does not coincide with the axis of the ventilation strut 5 , and the axis of the high-pressure pipeline 4 coincides with the axis of the gas collecting chamber 2 and the tail nozzle 1 .

[0050] The rear end of the high-pressure pipeline 4 is threadedly engaged with the ventilation support rod 5 , and the front end of the high-pressure pipeline 4 is plugged into the gas collecting chamber 2 through a cylindrical surface.

[0051] The high-pressure pipeline 4 and the ventilation support rod 5, as well as the high-pressure pipeline 4 and the gas collecting chamber 2 are sealed by using copper gaskets and sealing glue. The structure of the high-pressure pipeline 4 is shown in Figure 5 (a) (b).

[0052] The two ends of the tie rod 3 are fixedly connected to the gas collecting chamber 2 and the ventilation support rod 5 respectively; the front end of the tie rod 3 passes through the gas collecting chamber 2 and tightens and fixes the gas collecting chamber 2. The structure of the tie rod 3 is shown in Figure 4 (a) (b).

[0053] In order to ensure the strength and rigidity of the tie rod 3, the material of the tie rod 3 is steel with the grade of F141.

[0054] The tail nozzle 1 is fixed to the front end of the gas collecting chamber 2 in a threaded manner and serves as the outlet of the gas collecting chamber 2. The structure of the tail nozzle 1 is shown in Figure 2 (a) (b).

[0055] The pressure measuring point 6 is set at the tail end of the ventilation strut 5, and the jet pressure is measured by a high-pressure sensor. When the air flow velocity in the ventilation strut 5 is not large, the pressure value at this point can be used instead of the total jet pressure.

[0056] The plenum chamber 2 must be able to pass through at least two tie rods 3, leaving an inlet for the high-pressure pipeline 4 and a mounting hole for the tail nozzle 1. The plenum chamber 2 is designed to be machined in three sections and welded together as a single unit. The inner diameter of the middle section of the plenum chamber 2 is larger than that of the high-pressure pipeline 4, thus achieving high-pressure gas rectification. The structure of the plenum chamber 2 is shown in Figures 3(a)(b)(c).

[0057] Different from the conventional wind tunnel force test, the force balance 7 is not coaxial with the ventilation strut 5 to leave space for the high-pressure pipeline 4. The force balance 7 is designed to be located on the lower side of the ventilation strut 5 axis.

[0058] The test model is connected to the dynamometer 7 through a cone fit, and a certain gap is maintained between the test model and the tail nozzle 1, the gas collecting chamber 2, the pull rod 3, the high-pressure pipeline 4, and the ventilation support rod 5, with the gap value ranging from 2.5 to 3 mm.

[0059] The utility model realizes measuring the axial force of the test model while performing reverse jet flow by biasing the balance to one side of the ventilation support rod and moving the jet flow collecting chamber forward.

[0060] Example

[0061] Figures 2 to 7 illustrate the structure of a reverse jet system for wind tunnel testing. The ventilation strut 5 is rigidly connected to the wind tunnel angle of attack mechanism. To ensure airflow, its internal diameter is designed to be ≤38mm. To ensure strength and rigidity, its wall thickness is ≤6.5mm. A pressure measuring point 6 is located at the rear of the ventilation strut 5 to measure the total jet pressure within the strut 5, replacing the total jet pressure at the tail nozzle 1. The aperture of the pressure measuring point 6 is ≤3mm.

[0062] The rear end of the high-pressure pipe 4 is threadedly engaged with the vent strut 5, while the front end of the high-pressure pipe 4 is tightly fitted with the cylindrical surface of the plenum chamber 2. Both front and rear copper gaskets are used for sealing, with a thickness of ≤2mm. To ensure the airflow rate of the tail nozzle 1, the internal diameter of the high-pressure pipe 4 is ≤16mm.

[0063] The rear end of the pull rod 3 is threaded with the ventilation support rod 5, and the front end passes through the gas collecting chamber 2 and is pressed against the gas collecting chamber 2 through the head thread. To ensure the strength of the pull rod 3, its diameter is ≮10mm, and its material is F141 with an allowable stress of 1800MPa.

[0064] The front end of the plenum chamber 2 is connected to the tail nozzle 1 via threads. To ensure strength, the wall thickness should be ≤ 3mm. To ensure that the dynamometer 7 only measures the model's aerodynamic forces and jet interference forces, and not the direct jet forces, a certain clearance must be maintained between the tail nozzle 1, plenum chamber 2, tie rod 3, high-pressure pipeline 4, and ventilation support rod 5, with the model. The minimum clearance should be ≤ 1.5mm.

[0065] To ensure that the test model can be installed, the distance between the front end of the force measuring balance 7 and the rear end of the gas collecting chamber 2 is ≮35 mm.

[0066] When preparing for the test, you need to first fix the ventilation support rod 5, then install the high-pressure pipeline 4, the pull rod 3, and the force measuring balance 7, then install the rear end of the test model (the rear end of the test model is fixedly connected to the force measuring balance 7) and adjust the attitude angle of the model, then install the air collecting chamber 2 and the tail nozzle 1, and finally install the front section of the test model.

[0067] Although the present invention has been disclosed above in terms of preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art may, without departing from the spirit and scope of the present invention, make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and technical contents disclosed above. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A wind tunnel test reverse jet system structure, characterized in that: include: Tail nozzle (1), air collecting chamber (2), tie rod (3), high pressure pipeline (4), ventilation support rod (5) and force balance (7); The outer wall of the tail end of the ventilation strut (5) is fixedly connected to the wind tunnel angle of attack mechanism, and the tail end of the ventilation strut (5) is used to receive a high-pressure gas source input from a high-pressure pipeline; One end of the force balance (7) is fixedly connected to the front end surface of the ventilation support rod (5), and the other end of the force balance (7) is connected to the test model; The two ends of the high-pressure pipeline (4) are respectively connected to the gas collecting chamber (2) and the ventilation support rod (5); The two ends of the pull rod (3) are respectively fixedly connected to the gas collecting chamber (2) and the ventilation support rod (5); The tail nozzle (1) is fixed on the front end of the air collecting chamber (2) and serves as the outlet of the air collecting chamber (2).

2. A wind tunnel test reverse jet system structure according to claim 1, characterized in that: Both ends of the force measuring balance (7) are respectively processed with a truncated cone structure, which is used for fixed connection with the ventilation support rod (5) and the test model.

3. The reverse jet system structure for wind tunnel testing according to claim 1, characterized in that: The axis of the high-pressure pipeline (4) does not coincide with the axis of the ventilation support rod (5), and the axis of the high-pressure pipeline (4) coincides with the axis of the gas collecting chamber (2) and the tail nozzle (1); The axis of the force measuring balance (7) and the ventilation strut (5) do not coincide.

4. The reverse jet system structure for wind tunnel testing according to claim 1, characterized in that: The material of the pull rod (3) is steel, and the grade is F141.

5. The reverse jet system structure for wind tunnel testing according to claim 1, characterized in that: Also includes: Pressure measuring point (6); The pressure measuring point (6) is arranged at the tail end of the ventilation support rod (5), and the pressure measuring point (6) measures the jet pressure through a high-pressure sensor.

6. The reverse jet system structure for wind tunnel testing according to claim 1, characterized in that: The gas collecting chamber (2) is designed as a three-section structure which is processed separately and finally welded into a whole; The inner diameter of the middle section of the gas collecting chamber (2) is larger than the inner diameter of the high-pressure pipeline (4); The front end of the pull rod (3) passes through the three-section structure of the air collecting chamber (2) and tightens and fixes the three-section structure of the air collecting chamber (2).

7. The reverse jet system structure for wind tunnel testing according to claim 1, characterized in that: A certain gap is maintained between the test model and the tail nozzle (1), the air collecting chamber (2), the pull rod (3), the high-pressure pipeline (4), and the ventilation support rod (5), and the gap value range is 2.5 to 3 mm.

8. A wind tunnel test reverse jet system structure according to any one of claims 1 to 7, characterized in that: The rear end of the high-pressure pipeline (4) is threadedly matched with the ventilation support rod (5), and the front end of the high-pressure pipeline (4) is cylindrically plugged with the gas collecting chamber (2).

9. The reverse jet system structure for wind tunnel testing according to claim 8, characterized in that: The high-pressure pipeline (4) and the ventilation support rod (5), as well as the high-pressure pipeline (4) and the gas collecting chamber (2) are sealed by using copper gaskets and sealing glue.

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