Pulsed jet device for simulating surge conditions of micro turbojet engines

Abstract

The present application relates to a kind of pulse jet device for simulating surge condition of micro turbojet engine, jet unit and bleed air unit are all installed on test bench, and the environment simulation under the surge condition of micro turbojet engine test is realized by joint action;The bleed air unit uses external fan to supply stable high pressure airflow to jet unit by bleed air pipeline;The jet unit is located in gas collection cavity, and the phase of pulsating jet in subsection gas collection cavity is adjusted by adjusting pulsating jet angle by hydraulic unit and servo valve, and the simulation of engine surge condition is realized by the joint action of the two. The present application can realize the change of pulsating jet by changing the direction and phase of jet on the basis of micro turbojet engine test bench, and the simulation of micro turbojet engine surge condition caused by different influencing factors can be completed.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, specifically relating to a pulse jet device for simulating surge conditions in micro turbojet engines. Background Technology

[0002] In recent years, with the continuous development and progress of science and technology, drones have been widely used, and their applications in military and civilian fields have gradually increased. For a specific drone, the quality of its micro turbojet engine determines the overall performance of the aircraft, making relevant research of this type of aircraft of practical significance.

[0003] Unlike large aircraft, ground tests of micro turbojet engines for small UAVs focus more on the engine's thrust performance, but there are very few simulations of test runs under different operating conditions. As the scope of UAV use continues to expand, the working environment of UAVs will become very complex in the future. In order to extend the service life of UAVs and reduce the adverse effects of the environment, it is of great significance to simulate the surge condition of the engine in advance.

[0004] To date, experimental research on micro turbojet engines has mainly focused on measuring the engine's thrust performance. Existing technologies include the construction of six-degree-of-freedom thrust measurement rigs and simulation analysis of the entire engine start-up process; others have designed variable-size universal micro turbine engine test benches. However, research on surge faults and other aspects of micro turbojet engines is relatively limited.

[0005] Currently, the main method for conducting engine surge tests is fuel step injection. This method is complex to operate, carries significant risks, and is prone to causing safety accidents. The team led by Kuang Guilan at Nanjing University of Aeronautics and Astronautics achieved engine surge by introducing high-pressure gas after the compressor to block the flow path. However, their method involves introducing high-pressure gas through the existing air intake on the diffuser casing. This approach has a high failure rate and can only be applied to a single type of engine, lacking universality.

[0006] In summary, existing micro turbojet engine test benches lack the capability to conduct surge tests and cannot be adjusted for different engine models, thus failing to comprehensively evaluate and verify engine performance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pulse jet device for simulating the surge condition of a micro turbojet engine, which simulates the surge condition of a micro turbojet engine by changing different jet phases and jet angles.

[0008] The technical problem solved by this invention is achieved through the following technical solution:

[0009] A pulse jet device for simulating surge conditions in a micro turbojet engine is characterized by comprising a test bench, an air bleed unit, a hydraulic unit, and a jet unit. The air bleed unit and the hydraulic unit are mounted on the test bench, and the jet unit is installed inside the air bleed unit. The air bleed unit provides a stable air source for the jet device, and the jet unit operates through the hydraulic unit.

[0010] Furthermore, the test bench includes an engine, an L-shaped bracket, and a base plate. Two L-shaped brackets are bolted to the base plate, and the engine is fixedly installed between the two L-shaped brackets.

[0011] Furthermore, the bleed air unit includes a fan, a bleed air pipeline, a servo valve, and a gas collection chamber. The fan is fixedly installed on the base plate. The fan is connected to the gas collection chamber through the bleed air pipeline. A servo valve is installed on the bleed air pipeline. The gas collection chamber is bolted to the outer casing of the engine. When the fan is started, the gas collection chamber is filled with high-pressure gas and discharged through the jet unit.

[0012] Furthermore, the hydraulic unit includes a linear stepper motor, a force sensor, a hydraulic actuator, and hydraulic lines. The stepper motor is mounted on the base plate, the hydraulic actuator is connected to the base plate via a snap fastener, the force sensor is connected between the linear stepper motor and the hydraulic actuator, and the end of the hydraulic actuator is connected to the jet unit in the gas collection chamber via a hydraulic line.

[0013] Furthermore, the jet unit includes an annular hydraulic pipeline, a jet actuator, and a jet nozzle. The jet nozzle, the jet actuator, and the outer casing of the engine are all connected by hinges. The annular hydraulic pipeline and the jet actuator are connected by quick-connect couplings. The annular hydraulic pipeline is installed in the air collection chamber of the bleed air unit by a snap-fit. The annular hydraulic pipeline delivers liquid to move the jet actuator, which in turn drives the jet nozzle to rotate circumferentially.

[0014] Furthermore, the gas collection chamber includes four gas collection chamber units, which are connected by bolts to form a ring. The gas intake pipeline is divided into four branch pipelines corresponding to the four gas collection chamber units.

[0015] Furthermore, the jet nozzles consist of eight units, arranged circumferentially at equal intervals along the engine axis.

[0016] The advantages and beneficial effects of this invention are as follows:

[0017] 1. The present invention provides a pulse jet device for simulating surge conditions in micro turbojet engines. It employs an adjustable bleed air phase collection and bleed unit. By adjusting different phases during bleed air intake, different pulse jet impacts can be achieved, thereby simulating surge conditions caused by different phase factors in the engine.

[0018] 2. The pulse jet device of the present invention for simulating surge conditions of micro turbojet engines adopts an adjustable jet angle blade tip jet device. The jet nozzle can be adjusted within the range of 0 to 45°. By adjusting the angle, the surge conditions of micro turbojet engines under different jet angles can be simulated.

[0019] 3. The pulse jet device of the present invention for simulating surge conditions of micro turbojet engines can introduce external cooling airflow through the bleed air unit and jet unit after the engine test is completed, thereby accelerating the engine cooling speed, extending the engine service life, reducing the experimental cycle, and assisting the engine to extend the experimental time and increase the experimental frequency in high temperature environments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the jet unit of the present invention;

[0022] Figure 3 This is a schematic diagram showing the initial position of the jet unit of the present invention;

[0023] Figure 4 This is a schematic diagram showing the position of the jet unit during the simulated surge of the present invention;

[0024] Figure 5 This is a schematic diagram illustrating the working principle of the jet unit angle adjustment in this invention. Detailed Implementation

[0025] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0026] like Figure 1 , 2 As shown, a pulse jet device for simulating surge conditions in a micro turbojet engine is characterized by comprising a test bench 1, an air intake unit 2, a hydraulic unit 3, and a jet unit 4. The air intake unit 2 and the hydraulic unit 3 are mounted on the test bench 1, and the jet unit 4 is mounted inside the air intake unit 2. The air intake unit 2 provides a stable air source for the jet device, and the jet unit 4 operates through the action of the hydraulic unit 3.

[0027] The test bench 1 includes an engine 5, an L-shaped bracket 6 and a base plate 7. Two L-shaped brackets 6 are bolted to the base plate 7, and the engine 5 is fixedly installed between the two L-shaped brackets 6.

[0028] The air intake unit 2 includes a fan 8, an air intake pipe 9, a servo valve 10, and an air collection chamber 11. The fan 8 is fixedly installed on the base plate 7. The fan 8 is connected to the air collection chamber 11 through the air intake pipe 9. The servo valve 10 is installed on the air intake pipe 9. The air collection chamber 11 is bolted to the outer casing of the engine 5. When the fan 8 is started, the air collection chamber 11 is filled with high-pressure gas and discharged through the jet unit 4.

[0029] The gas collection chamber 11 includes four gas collection chamber units, which are connected by bolts to form a ring. The gas duct 9 is divided into four branch pipes corresponding to the four gas collection chamber units. By adjusting the servo valve (10), the four gas collection chamber units can be filled with high-pressure gas in a specific order to achieve the phase change of the pulse jet.

[0030] The hydraulic unit 3 includes a linear stepper motor 12, a force sensor 13, a hydraulic actuator 14, and a hydraulic pipeline 15. The stepper motor 12 is mounted on the base plate 7. The hydraulic actuator 14 is connected to the base plate 7 by a buckle. The force sensor 13 is connected between the linear stepper motor 12 and the hydraulic actuator 14. The end of the hydraulic actuator 14 is connected to the jet unit 4 in the gas collection chamber 11 through the hydraulic pipeline 15. When a signal is received, the linear stepper motor (12) pushes the force sensor (13) and the hydraulic actuator (14) to move in a straight line and stops when the predetermined jet angle is reached.

[0031] The jet unit 4 includes an annular hydraulic pipeline 16, a jet actuator 17, and a jet nozzle 18. The jet nozzle 18, the jet actuator 17, and the outer casing of the engine 5 are all connected by hinges. The annular hydraulic pipeline 16 and the jet actuator 17 are connected by quick-connect couplings. The annular hydraulic pipeline 16 is installed in the air collection chamber 11 of the air intake unit 2 by snap-fit. The annular hydraulic pipeline 16 delivers liquid to make the jet actuator 17 move, which drives the jet nozzle 18 to rotate circumferentially, thereby changing the airflow at the diffuser (20) of the centrifugal compressor (19) of the micro turbojet engine.

[0032] The jet nozzles consist of 8 nozzles arranged circumferentially at equal intervals along the engine axis 5.

[0033] The working principle of this invention is as follows:

[0034] The working principle of this invention is as follows:

[0035] I. Before the device introduces the jet: Figure 3The diagram shows the position of the jet nozzle before the jet is introduced. At this time, the jet nozzle 18 is closed with the outer casing of the engine 5, there is no external jet introduced, the engine 5 is running normally, the hydraulic actuator 14 is in the starting position, and the air pressure in the gas collecting chamber 11 is balanced with the engine air pressure. At this time, the test can be carried out under the normal working condition of the engine.

[0036] II. When the device introduces jets at different angles to simulate surge: Figure 4 The diagram shows the position of the jet nozzle during surge simulation. At this time, the hydraulic unit receives a start signal, and the linear stepper motor 12 drives the force sensor 13 and the hydraulic actuator 14 to move in a straight line, causing the jet nozzle 18 to rotate circumferentially. After reaching a specified angle, the force sensor 13 feeds back a signal to stop the hydraulic actuator 14 from moving. The high-pressure airflow inside the gas collection chamber 11 is ejected along the jet nozzle 18, which ultimately changes the flow inside the engine and realizes the simulation of surge condition.

[0037] III. When the device introduces jets of different phases to simulate surge: High-pressure airflow is introduced through an external fan (8) and delivered to the gas collection chamber (11) through the bleed air pipeline (9). The servo valve (10) connected to the gas collection chamber of the required phase is adjusted as needed. The jet nozzle (18) rotates along the circumference of the engine under the action of the hydraulic unit, so that the high-pressure airflow inside the gas collection chamber (11) of different phases is ejected along the jet nozzle (18), which changes the gas flow in the diffuser (20) part of the centrifugal compressor (19) to realize the simulation of engine surge condition.

[0038] The simulation of surge conditions described above is applicable not only to the single adjustment of jet angle and expiratory phase, but also to the coupled adjustment of the two.

[0039] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A pulse jet device for simulating surge conditions in a micro turbojet engine, characterized in that: It includes a test bench (1), an air intake unit (2), a hydraulic unit (3) and a jet unit (4). The air intake unit (2) and the hydraulic unit (3) are installed on the test bench (1). The jet unit (4) is installed inside the air intake unit (2). The air intake unit (2) provides a stable air source for the jet device. The jet unit (4) operates through the hydraulic unit (3). The test bench (1) includes an engine (5), an L-shaped bracket (6) and a base plate (7). Two L-shaped brackets (6) are bolted on the base plate (7), and the engine (5) is fixedly installed between the two L-shaped brackets (6). The air intake unit (2) includes a fan (8), an air intake pipeline (9), a servo valve (10), and an air collection chamber (11). The hydraulic unit (3) includes a linear stepper motor (12), a force sensor (13), a hydraulic actuator (14), and a hydraulic pipeline (15). The stepper motor (12) is mounted on the base plate (7). The hydraulic actuator (14) is connected to the base plate (7) by a buckle. The force sensor (13) is connected between the linear stepper motor (12) and the hydraulic actuator (14). The end of the hydraulic actuator (14) is connected to the jet unit (4) in the gas collection chamber (11) through the hydraulic pipeline (15).

2. The pulse jet device for simulating surge conditions in a micro turbojet engine according to claim 1, characterized in that: The fan (8) is fixedly installed on the base plate (7). The fan (8) is connected to the air collection chamber (11) through the air intake pipe (9). A servo valve (10) is installed on the air intake pipe (9). The air collection chamber (11) is bolted to the outer casing of the engine (5). When the fan (8) is started, the air collection chamber (11) is filled with high-pressure gas and discharged through the jet unit (4).

3. The pulse jet device for simulating surge conditions in a micro turbojet engine according to claim 1, characterized in that: The jet unit (4) includes an annular hydraulic pipeline (16), a jet actuator (17), and a jet nozzle (18). The jet nozzle (18) is connected to the jet actuator (17) and the outer casing of the engine (5) by hinges. The annular hydraulic pipeline (16) and the jet actuator (17) are connected by quick-connect couplings. The annular hydraulic pipeline (16) is installed in the air collection chamber (11) of the air intake unit (2) by snap-fit. The annular hydraulic pipeline (16) delivers liquid to make the jet actuator (17) move, which drives the jet nozzle (18) to rotate circumferentially.

4. The pulse jet device for simulating surge conditions in a micro turbojet engine according to claim 1, characterized in that: The gas collection chamber (11) includes four gas collection chamber units, which are connected by bolts to form a ring. The gas duct (9) is divided into four branch ducts and corresponds to the four gas collection chamber units.

5. The pulse jet device for simulating surge conditions in a micro turbojet engine according to claim 3, characterized in that: The jet nozzles (18) are eight in number and are arranged circumferentially at equal intervals along the axis of the engine (5).

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