Cold-flow binary supersonic separation line nozzle performance and flow schlieren test bench

Abstract

This invention discloses a test bench for testing the performance and flow schlieren of a cold-flow binary supersonic split-line nozzle. The bench comprises a support structure, an air supply structure, a servo actuation system, and a supersonic split-line nozzle. The support structure includes a base and a thrust frame, on which a nozzle support frame and an inlet section support frame are mounted. The air supply structure includes an inlet section, a transition section, and a connecting section connected sequentially by flanges. The front end of the inlet section is connected to the thrust frame, and the lower part of the inlet section is supported by the inlet section support frame. This invention can reproduce the working process of a supersonic split-line nozzle under different swing angles and oscillation speeds under ground experimental conditions. It uses a schlieren system and pressure sensors to acquire the flow state and wall pressure distribution characteristics of the binary nozzle, respectively, for testing the nozzle's working state under high-pressure cold-flow nitrogen input conditions. It has the advantages of high adaptability and accurate measurement.

Description

Technical Field

[0001] This invention belongs to the field of nozzle testing and inspection in aerospace testing technology, specifically relating to a test stand for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle. Background Technology

[0002] Supersonic split-line nozzles are oscillating nozzles capable of achieving thrust vectoring effects. They offer advantages such as large deflection angles, lightweight construction, and excellent sealing, providing superior thrust vectoring performance for aircraft. A typical supersonic split-line nozzle consists of a fixed section, a movable section, connecting components, and an actuation mechanism. The actuation mechanism controls the oscillation of the movable section, deflecting the airflow to achieve the thrust vectoring effect. During the oscillation of the movable section, complex flow phenomena occur, including shock wave reflection on solid walls, shock wave-shock wave interactions, and flow separation. This presents challenges for the design and performance improvement of supersonic split-line nozzles. Revealing the internal flow evolution during the operation of supersonic split-line nozzles and exploring the mechanisms influencing their thrust vectoring characteristics are crucial for their design and performance enhancement.

[0003] Existing supersonic split-line oscillating nozzle experimental setups have certain limitations in experimental research. The main limitation is the inability to achieve real-time flow field observation while the nozzle is oscillating. This not only restricts in-depth analysis of the nozzle flow characteristics but also reduces the efficiency of experimental data acquisition. Furthermore, the nozzle profile replacement process of traditional devices is relatively complex, making it difficult to meet the rapid adjustment requirements under various operating conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a test bench for testing the performance and flow schlieren of a cold-flow binary supersonic split-line nozzle. Under ground experimental conditions, the test bench can reproduce the working state of the supersonic split-line nozzle at different swing angles, realize and observe the swing process of the supersonic split-line nozzle, and has considerable application prospects in supersonic split-line nozzle flow field observation and performance improvement.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A test bench for testing the performance and flow schlieren of a cold-flow binary supersonic split-line nozzle includes: a support structure, an air supply structure, a servo actuation system, and a supersonic split-line nozzle;

[0007] The support structure includes a base and a thrust frame, and a nozzle support frame and an air intake section support frame are installed on the base.

[0008] The air supply structure includes an air intake section, a transition section, and a connecting section connected in sequence by flanges. The front end of the air intake section is connected to the thrust frame, and the lower part of the air intake section is supported by the air intake section support frame.

[0009] The servo actuation system includes the servo mechanism, which is connected to the upper servo mechanism support frame and the lower servo mechanism support frame respectively. The servo mechanism is connected to the guide arm, which is limited by the nozzle side baffle and the nozzle side baffle cover. The nozzle side baffle is connected to the upper side of the nozzle support frame.

[0010] The supersonic separation line nozzle includes a movable component, which is connected to an acrylic plate and a nozzle side baffle. The acrylic plate and the acrylic baffle are sealed by an arc-shaped sealing strip. The acrylic baffle is connected to the nozzle side baffle and a fixing component, respectively. The fixing component and the movable component are sealed by a sealing strip. A high-frequency pressure sensor is connected to the wall surface of the movable component to measure the wall surface pressure. The movable component moves by driving the guide arm through the servo mechanism.

[0011] Furthermore, the air intake section has an air intake hole, which is connected to the air supply system through a pipeline to input high-pressure, high-flow-rate gas.

[0012] Furthermore, the internal channel of the transition section is changed from circular to square to change the cross-sectional shape of the gas flow, transforming the circular cross-section into a square cross-section.

[0013] Furthermore, the internal channel of the connecting section is square, which further rectifies the airflow and ensures that the airflow direction and speed entering the supersonic separation line nozzle are consistent.

[0014] Furthermore, the acrylic sheet is a high-transparency acrylic sheet.

[0015] Furthermore, the fixed component and the movable component have pressure measuring holes for mounting the high-frequency pressure sensor (18) to measure the pressure at different positions on the wall surface of the fixed component and the movable component.

[0016] Furthermore, the front end of the air intake section is connected to a thrust sensor via a thrust bracket to record the thrust of the supersonic splitter nozzle.

[0017] Furthermore, the arc-shaped sealing strip is a rigid rubber strip.

[0018] The present invention may also include:

[0019] A method for testing the performance and flow schlieren of a cold-flow binary expansion deflection nozzle using the aforementioned test stand, the method comprising:

[0020] Step 1: Install the test bench and sensors, connect the data acquisition system, and check whether the sensors are connected properly;

[0021] Step 2: Adjust the schlieren system to ensure that the target area is clearly and completely imaged in the camera. Turn on the camera to start recording, and at the same time turn on the data acquisition system to record the test pressure and thrust data.

[0022] Step 3: Start the experiment. Open the pneumatic valve and input high-pressure nitrogen into the gas supply system to obtain a stable airflow for a period of time.

[0023] Step 4: Close the pneumatic valve, shut down the data acquisition system, and turn off camera recording. The experiment is now complete.

[0024] Furthermore, when the experiment begins, the test stand controls the servo mechanism to move the guide arm, which in turn moves the movable part and the acrylic plate. At the same time as the servo mechanism is working, high-pressure gas enters the intake section through the intake hole below the intake section. The gas cross-sectional shape changes from circular to square through the transition section, and then flows into the connecting section to form a uniform and stable airflow into the supersonic separation line nozzle. The gas expands in the supersonic separation line nozzle to generate thrust.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention enables cold flow tests during the oscillation process of supersonic separator nozzles and real-time flow state observation and wall pressure monitoring, thereby obtaining the flow evolution and performance change laws during the operation of supersonic separator nozzles and providing technical support for supersonic separator nozzle profile design and performance improvement.

[0027] The cold-flow binary supersonic splitter nozzle performance and flow schlieren test bench proposed in this invention can reproduce the working state of the binary supersonic splitter nozzle. It realizes the dynamic swing of the nozzle moving parts through a servo mechanism to reproduce the swing process of the supersonic splitter nozzle in actual operation. It obtains the flow characteristics of the nozzle wall by measuring the pressure distribution of the nozzle wall through a pressure sensor, collects the thrust characteristics of the nozzle through a thrust sensor, and captures the flow field wave system through a schlieren system.

[0028] The cold flow binary supersonic separation line nozzle performance and flow schlieren test bench proposed in this invention can reproduce the working state under different swing angles through a servo actuation system without replacing parts, and measure the influence of the swing angle on the working state of the nozzle to the greatest extent possible under limited test conditions.

[0029] The cold-flow binary supersonic separator nozzle performance and flow schlieren testing test stand proposed in this invention has advantages over other test stands in terms of measurement accuracy and observability. Pressure sensors are installed on the walls of both fixed and moving parts to achieve real-time pressure monitoring; high-transmittance acrylic plates are used to obtain flow schlieren images during operation.

[0030] The cold-flow binary supersonic split-line nozzle performance and flow schlieren test stand proposed in this invention can conduct nozzle tests with different profiles. While keeping other components of the test stand unchanged, only the fixed parts, moving parts, and acrylic plate need to be replaced to conduct cold-flow tests on the working process of supersonic split-line nozzles with different profiles. The replacement process is simple and efficient, significantly improving test efficiency.

[0031] This invention not only enables the nozzle to oscillate but also allows for the visualization and observation of the flow field during the oscillation process, ensuring the comprehensiveness and accuracy of experimental data. The device employs a modular design, making nozzle profile replacement more convenient and significantly improving experimental flexibility and adaptability. It provides a more efficient and precise experimental method for studying supersonic flow in nozzles, contributing to the in-depth exploration and development of related fields. Attached Figure Description

[0032] Appendix Figure 1 This is a schematic diagram of the structure of the present invention.

[0033] Appendix Figure 2 This is a schematic diagram of the support structure and gas supply structure of the present invention.

[0034] Appendix Figure 3 This is a cross-sectional view of the support structure and the gas supply structure of the present invention.

[0035] Appendix Figure 4 This is an assembly diagram of the servo actuation system and supersonic separation line nozzle of the present invention.

[0036] Appendix Figure 5 This is a partial structural assembly diagram of the supersonic separation line nozzle of the present invention.

[0037] Appendix Figure 6 This is a schematic diagram of the structure of the acrylic baffle of the present invention.

[0038] In the diagram: 1-Base; 2-Nozzle support frame; 3-Connecting section; 4-Transition section; 5-Intake section; 6-Thrust frame; 7-Intake section support frame; 8-Intake port; 9-Upper servo mechanism support frame; 10-Lower servo mechanism support frame; 11-Servo mechanism; 12-Nozzle side baffle; 13-Nozzle side baffle cover; 14-Guide arm; 15-Acrylic plate; 16-Acrylic baffle; 17-Fixed component; 18-Pressure sensor; 19-Moving component; 20-Sealing strip; 21-Arc-shaped sealing strip. Detailed Implementation

[0039] The present invention will now be further described with reference to the accompanying drawings.

[0040] This invention provides a test bench for testing the performance and flow schlieren of a cold-flow binary expansion deflection nozzle, such as... Figure 1-6As shown, its components include: a support structure, an air supply structure, a servo actuation system, and a supersonic separation line nozzle, wherein:

[0041] As attached Figure 2 As shown, the support structure includes a base 1, a nozzle support frame 2, a thrust frame 6, and an intake section support frame 7;

[0042] The base 1 is connected to the nozzle support frame 2 and the air intake section support frame 7;

[0043] The thrust frame 6 is connected to the air intake section 5 via a flange, the air intake section 5 is connected to the transition section 4 via a flange, the transition section 4 is connected to the connecting section 3 via a flange, and the connecting section 3 is connected to the fastener 17 of the supersonic separation line nozzle via a flange.

[0044] In this embodiment, the base 1 is the main load-bearing structure.

[0045] In this embodiment, the intake section support frame 7 is an important support device used to support the intake section 5, provide support for the engine, and keep the engine level.

[0046] More specifically, the nozzle support frame 2 and the air intake section support frame 7 are fixedly connected to the base 1 by bolts. The air intake section support frame 7 supports the air intake section 5, and the air intake section 5 is connected to the thrust frame 6, which can be used for thrust measurement.

[0047] In this embodiment, the transition section 4 is a pipe segment in which the internal channel changes from a circle to a square, which is used to change the cross-sectional shape of the gas flow and transition the circular cross-section to a square cross-section.

[0048] In this embodiment, the connecting section 3 is a square pipe that further rectifies the airflow to ensure that the airflow direction and speed entering the supersonic separation line nozzle are consistent.

[0049] In this embodiment, the pressure hole 8 is connected to the gas supply system through a pipeline to connect the gas supply system and the air intake section 5. When the equipment is working, the high-pressure nitrogen provided by the gas supply system flows into the air intake section 5 through the pressure hole 8 to provide high-pressure gas for the supersonic separation line nozzle.

[0050] In this embodiment, the front end of the air intake section 5 is connected to the thrust sensor via the thrust frame 6, thereby generating supersonic separation line nozzle thrust.

[0051] As attached Figure 3 As shown, the gas supply structure includes an air inlet section 5, a transition section 4, a connecting section 3, and an air inlet 8; the air inlet 8 is installed on the air inlet section 5, and the air inlet 8 is connected to the gas supply system through a pipeline to provide high-pressure, high-flow gas; the lower part of the air inlet section 5 is connected to the air inlet section support frame 7.

[0052] As attached Figure 4As shown, the servo actuation system includes an upper servo mechanism support frame 9, a lower servo mechanism support frame 10, a servo mechanism 11, a nozzle side baffle 12, a nozzle side baffle cover 13, and a guide arm 14.

[0053] In this embodiment, the servo mechanism 11 is connected to an upper servo mechanism support frame 9 and a lower servo mechanism support frame 10, and the lower servo mechanism support frame 10 is connected to the nozzle support frame 2.

[0054] The guide arm 14 is connected to a servo mechanism 11 and a movable part 19. The servo mechanism 11 drives the guide arm 14 to move, thereby enabling the movable part 19 to move.

[0055] The nozzle side baffle 12 is connected to the nozzle side baffle cover 13 to limit the guide arm 14;

[0056] The supersonic separation line nozzle consists of an acrylic plate 15, an acrylic baffle 16, a fixing component 17, a moving component 19, a sealing strip 20, a pressure sensor 18, and an arc-shaped sealing strip 21.

[0057] The wall surface of the movable part 19 of the supersonic separation line nozzle is connected to a high-frequency pressure sensor 18 to measure the wall pressure. An acrylic baffle 12 is connected to the side of the movable part 19. The nozzle side baffle 12 is connected to the upper side of the nozzle support frame 2, and the lower side of the nozzle support frame 2 is connected to the base 1.

[0058] The movable part 19 is connected to an acrylic plate 15, and the acrylic plate 15 and the acrylic baffle 16 are sealed by an arc-shaped sealing strip 21.

[0059] The acrylic baffle 16 is connected to the nozzle side baffle 12 and the fixing member 17, and the fixing member 17 and the movable member 19 are sealed by the sealing strip 20.

[0060] The supersonic separation line nozzle described in this embodiment is a binary planar nozzle, its profile consisting of a fixed component 17 and a movable component 19, with its inner surface serving as the experimental section for airflow contact. The fixed component 17 has one pressure measurement hole, and the movable component 19 has four pressure measurement holes for mounting pressure sensors 18, which can measure the pressure distribution at different locations on the wall. The fixed component 17 is connected to the connecting section 3 via a flange; gas enters the supersonic separation line nozzle through the connecting section 3 and expands before exiting. The fixed component 17 cooperates with the nozzle side baffle 12 to press against the acrylic baffle 16, which in turn presses against the acrylic plate 15. A sealing strip 20 is used between the acrylic baffle 16 and the acrylic plate 15 to improve airtightness. The acrylic plate 15 has threaded holes for bolt connection with the movable component 19, enabling synchronous movement of the acrylic plate 15 and the movable component 19 during operation. The movable part 19 has a threaded hole on its wall for connecting with the guide arm 14, and the guide arm 14 is connected to the servo mechanism 11.

[0061] The guide arm 14 is an arc-shaped connector.

[0062] The acrylic baffle 16 described in this embodiment is a semi-circular baffle used to press the acrylic plate 15. It ensures the airtightness of the connection through the sealing strip 20. This connection method provides good airtightness while realizing relative movement between the acrylic plate 15 and the fixing member 17.

[0063] Preferably, the acrylic sheet 15 has high transparency and good toughness, and can be photographed and recorded using a schlieren system.

[0064] In this embodiment, the servo actuation system is assembled with the supersonic separation line nozzle as follows: The nozzle fixing component 17 is connected to the connecting section 3 via a flange. The lower servo mechanism support component 10 is bolted to the nozzle support frame 2 to fix the lower servo mechanism support component 10. The nozzle side baffle 12 is bolted to the lower servo mechanism support component 10, and the acrylic baffle 16 is pressed against the fixing component 17 by the nozzle side baffle 12. The acrylic plate 15 is pressed against the moving component 19 by the acrylic baffle 16, and the acrylic plate 15 and the moving component 19 are connected by bolts. This connection method allows for the coordinated movement between the acrylic plate 15 and the moving component 19, enabling flow field observation during the nozzle oscillation process.

[0065] During operation, the servo mechanism 11 is activated, driving the guide arm 14 to move, which in turn drives the movable part 19 and the acrylic plate 15 to move. Simultaneously, high-pressure gas enters the intake section 5 through the intake port 8 below it. The transition section 16 changes the gas cross-sectional shape from circular to square, and the gas then flows into the connecting section 3, forming a uniform and stable airflow that enters the supersonic separation line nozzle. Within the nozzle, the gas expands, generating thrust.

[0066] While the servo mechanism is operating, high-pressure gas enters the intake section 5 through the intake port 8 below the intake section 5. The gas cross-sectional shape changes from circular to square through the transition section 16, and then flows into the connecting section 3 to form a uniform and stable airflow that enters the supersonic separation line nozzle. Within the nozzle, the gas expands to generate thrust. Pressure measuring holes are provided on the walls of both the moving part 19 and the fixed part 17 of the nozzle, allowing for the measurement of the wall pressure distribution and real-time pressure changes during the experiment. A schlieren system is used to record the flow field schlieren image through the acrylic plate 15.

[0067] The stroke of the servo mechanism described in this embodiment can be selected as 50mm.

[0068] As attached Figure 5As shown, the gap between the fixed part 17 and the movable part 19 is sealed with a sealing strip 20 to ensure airtightness. One pressure measuring hole is provided on the inner surface of the fixed part 17, and four pressure measuring holes are provided on the inner surface of the movable part 19. Pressure sensors 18 are connected to the outer surface of each part.

[0069] As attached Figure 6 The figure shows the assembly diagram of the acrylic baffle 16 and the arc-shaped sealing strip 21. The acrylic baffle 16 presses the acrylic plate 15 against the side wall of the nozzle. An arc-shaped groove is provided on the mating surface of the acrylic baffle 16 and the acrylic plate 15 to accommodate the arc-shaped sealing strip 21, thereby further improving the airtightness of the connection between the acrylic baffle 16 and the acrylic plate 15.

[0070] This embodiment also provides a method for testing the performance and flow schlieren of a cold-flow binary expansion deflection nozzle using the above-mentioned test stand, the method comprising:

[0071] Step 1: Install the test bench and sensors, connect the data acquisition system, and check whether the sensors are connected properly;

[0072] Step 2: Adjust the schlieren system to ensure that the target area is clearly and completely imaged in the camera. Turn on the camera to start recording, and at the same time turn on the data acquisition system to record the test pressure and thrust data.

[0073] Step 3: Start the experiment. Open the pneumatic valve and input high-pressure nitrogen into the gas supply system to obtain a stable airflow for a period of time.

[0074] Step 4: Close the pneumatic valve, shut down the data acquisition system, and turn off camera recording. The experiment is now complete.

[0075] The supersonic separation line nozzle test procedure is as follows: Before the test begins, the equipment for recording test data is turned on to start recording. Then, the gas supply system valve is opened to supply high-pressure nitrogen into the engine. After a period of time, the gas supply is stopped, the test data is saved, the total pressure of the nitrogen flowing in is changed to repeat the test, and the test results are analyzed and summarized.

[0076] Using the above technical solution, the test stand of this invention can reproduce the working process of a supersonic split-line nozzle under different swing angles and different swing velocities under ground test conditions. By using a schlieren system and a pressure sensor to obtain the flow state and wall pressure distribution characteristics of the binary nozzle, it is used to test the working state of the supersonic split-line nozzle under high-pressure cold nitrogen input conditions. It has the advantages of simple principle, high adaptability, and accurate measurement of working state, and has good application prospects for supersonic split-line nozzle testing.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle, characterized in that, include: Support structure, air supply structure, servo actuation system, and supersonic separation line nozzle; The support structure includes a base (1) and a thrust frame (6), and a nozzle support frame (2) and an air intake section support frame (7) are installed on the base (1); The air supply structure includes an air intake section (5), a transition section (4), and a connecting section (3) connected in sequence by flanges. The front end of the air intake section (5) is connected to the thrust frame (6), and the lower part of the air intake section (5) is supported by the air intake section support frame (7). The servo actuation system includes a servo mechanism (11), which is connected to the upper servo mechanism support frame (9) and the lower servo mechanism support frame (10) respectively. The servo mechanism (11) is connected to the guide arm (14), which is limited by the nozzle side baffle (12) and the nozzle side baffle cover (13). The nozzle side baffle (12) is connected to the upper side of the nozzle support frame (2). The supersonic separation line nozzle includes a movable part (19), which is connected to an acrylic plate (15) and a nozzle side baffle (12). The acrylic plate (15) and the acrylic baffle (16) are sealed by an arc-shaped sealing strip (21). The acrylic baffle (16) is connected to the nozzle side baffle (12) and a fixing part (17) respectively. The fixing part (17) and the movable part (19) are sealed by a sealing strip (20). A high-frequency pressure sensor (18) is connected to the wall of the movable part (19) to measure the wall pressure. The movable part (19) drives the guide arm (14) to move through the servo mechanism (11).

2. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1, characterized in that, The air intake section (5) has an air intake hole (8), which is connected to the air supply system through a pipeline to input high-pressure, high-flow gas.

3. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1 or 2, characterized in that, The internal channel of the transition section (4) is changed from a circle to a square to change the cross-sectional shape of the gas flow, and to transition the circular cross-section to a square cross-section.

4. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1 or 2, characterized in that, The internal channel of the connecting section (3) is square, which further rectifies the airflow and ensures that the airflow direction and speed entering the supersonic separation line nozzle are consistent.

5. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1, characterized in that, The acrylic sheet (15) is a high-transparency acrylic sheet.

6. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1 or 2, characterized in that, The fixed member (17) and the movable member (19) have pressure measuring holes for installing the high-frequency pressure sensor (18) to measure the pressure at different positions on the wall of the fixed member (17) and the movable member (19).

7. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1 or 2, characterized in that, The front end of the air intake section (5) is connected to the thrust sensor via the thrust frame (6) to record the thrust of the supersonic separation line nozzle.

8. The test bench for testing the performance and flow schlieren of a cold-flow binary supersonic separation line nozzle according to claim 1 or 2, characterized in that, The arc-shaped sealing strip (21) is a hard rubber strip.

9. A method for testing the performance and flow schlieren of a cold-flow binary expansion deflection nozzle using the test stand described in any one of claims 1-8, characterized in that, The method includes: Step 1: Install the test bench and sensors, connect the data acquisition system, and check whether the sensors are connected properly; Step 2: Adjust the schlieren system to ensure that the target area is clearly and completely imaged in the camera. Turn on the camera to start recording, and at the same time turn on the data acquisition system to record the test pressure and thrust data. Step 3: Start the experiment. Open the pneumatic valve and input high-pressure nitrogen into the gas supply system to obtain a stable airflow for a period of time. Step 4: Close the pneumatic valve, shut down the data acquisition system, and turn off camera recording. The experiment is now complete.

10. The method for testing the performance and flow schlieren of a cold-flow binary expansion deflection nozzle on the test stand according to claim 9, characterized in that, When the experiment begins, the test bench controls the servo mechanism (11) to move the guide arm (14), and the guide arm (14) then moves the movable part (19) and the acrylic plate (15). At the same time as the servo mechanism is working, high-pressure gas enters the intake section (5) through the intake hole (8) below the intake section (5), and changes the gas cross-sectional shape from circular to square through the transition section (16), and then flows into the connecting section (3) to form a uniform and stable airflow into the supersonic separation line nozzle, where it expands to generate thrust.

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