Isobaric fuel supply system for shock tunnel engine test and its design and test method

Abstract

The present invention belongs to the technical field of wind tunnel tests, and discloses an isobaric fuel supply system for shock tunnel engine tests and a design and test method. The isobaric fuel supply system includes a gas distribution device, a pressure stabilizing device, a delayed trigger device and a control system; the gas distribution device is used for automatic charging and discharging of pressure stabilizing gas and fuel gas of different pressures; the pressure stabilizing device is driven by an electromagnetic piston, and the pressure stabilization is achieved by driving the piston through the pressure stabilizing gas and electromagnetic force compensation; the delayed trigger device is used for triggering control of the rapid electromagnetic valve of the injection port to ensure the synchronization of the shock tunnel flow and the fuel gas injection. It is suitable for fuel injection simulation in ground test research of shock tunnel engines. The design and test method of the isobaric fuel supply system includes designing and processing a pressure stabilizing cylinder; designing and processing an air storage pipe; installing and debugging a fuel supply system; and conducting shock tunnel engine tests. It can achieve isobaric supply of engine model fuel within the test time, improve test accuracy, and has engineering practical value.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel tests, and in particular relates to an isobaric fuel supply system for shock wave wind tunnel engine tests and a design and test method thereof. Background Art

[0002] Shock wind tunnels can reproduce the high total temperature and high total pressure conditions of airflow in the actual flight environment of aircraft, and are the main equipment for conducting engine ground test research. Since the operating time of shock wind tunnels is relatively short, how to achieve rapid fuel supply with stable pressure and accurate flow within a relatively short effective test time has become a key technology for engine ground testing.

[0003] At present, conventional fuel supply systems use two methods: first, built-in buffer tanks and pressure-stabilizing chambers are used to reduce along-the-line losses. However, the pressure attenuation of this method is uncontrollable. Second, compensating gas drive is used to reduce the pressure attenuation index. However, this method is limited by the geometric structure and usually requires the volume of compensating gas to be large enough to ensure that the attenuation index of the injection pressure within the test time meets the requirements. This is more difficult to achieve for situations with higher pressures and requirements.

[0004] Currently, there is an urgent need to develop an isobaric fuel supply system for shock tunnel engine testing as well as its design and testing methods. Summary of the invention

[0005] One technical problem to be solved by the present invention is to provide an isobaric fuel supply system for shock wind tunnel engine tests. Another technical problem to be solved by the present invention is to provide a design and test method for an isobaric fuel supply system for shock wind tunnel engine tests to overcome the defects of the prior art.

[0006] The shock wave wind tunnel engine test isobaric fuel supply system of the present invention comprises a gas distribution device, a pressure stabilizing device and a delayed trigger device, and a control system for controlling the operation of the gas distribution device, the pressure stabilizing device and the delayed trigger device;

[0007] The gas distribution device includes a pressure-stabilizing gas branch and a fuel branch; the pressure-stabilizing gas branch delivers pressure-stabilizing gas of a preset pressure to the gas storage pipe of the pressure-stabilizing device, and the inlet end of the pressure-stabilizing gas branch includes a pressure-stabilizing gas source and a pressure-stabilizing gas shut-off valve connected in sequence; the rear end of the pressure-stabilizing gas shut-off valve is divided into a parallel pressure-reducing gas circuit and a pressure-boosting gas circuit along the air intake direction, the pressure-reducing gas circuit is connected in sequence to the programmable pressure-reducing valve and the electromagnetic shut-off valve II, and the pressure-boosting gas circuit is connected in sequence to the gas booster pump and the electromagnetic shut-off valve I; the outlet end of the pressure-stabilizing gas branch is connected to the gas storage pipe; the fuel branch delivers fuel gas of a preset pressure to the fuel cavity of the pressure-stabilizing cylinder of the pressure-stabilizing device, and the fuel branch includes a fuel gas source, and the rear end of the fuel gas source is connected in sequence to a filter, a fuel shut-off valve, a pressure gauge, a one-way valve, and a fuel intake shut-off valve along the air intake direction, wherein the one-way valve and the fuel intake shut-off valve are located in the test cabin, and finally connected to the fuel cavity at the outlet end of the pressure-stabilizing cylinder;

[0008] The pressure stabilizing device comprises an air storage pipe and a pressure stabilizing cylinder; the pressure stabilizing cylinder is an electromagnetic piston driven air cylinder, the inner cavity of the pressure stabilizing cylinder is divided into two sections by the piston, the front section is the pressure stabilizing air cavity at the inlet end, and the rear section is the fuel cavity at the outlet end; the outer wall surface of the cylinder body of the pressure stabilizing cylinder is surrounded by M groups of annular winding coils, and each group of annular winding coils is equipped with an independent power supply; the piston is a T-shaped piston, the vertical section of the T-shaped piston is a piston sheet matching the cross-sectional shape of the inner cavity of the pressure stabilizing cylinder, and the horizontal section of the T-shaped piston is a column section, and the column section is surrounded by an induction coil; the outlet end of the air storage pipe is connected to the shock wave wind tunnel test cabin through a flange, and the pressure stabilizing air electromagnetic stop valve and the pressure stabilizing air cavity at the inlet end of the pressure stabilizing cylinder are connected in sequence through a pipeline in the test cabin, and the fuel cavity at the outlet end of the pressure stabilizing cylinder is connected to the fast electromagnetic valve;

[0009] The delayed trigger device includes a trigger sensor installed on the shock tube of the shock tunnel. The trigger sensor is connected to the solid-state relay and the fast solenoid valve in sequence through the control system, and finally connected to the fuel injection module on the model. The trigger sensor achieves the synchronization of the fuel injection on the model with the shock tunnel flow by setting the delay time, and controls the duration of the fuel injection at the same time.

[0010] Furthermore, the gas medium of the pressure-stabilized gas source is N 2 , He or Air.

[0011] Furthermore, a drain branch is provided at the front end of the one-way valve of the fuel branch, and the drain branch is provided with a connection to an electromagnetic stop valve IV.

[0012] Furthermore, the gas storage pipe is a segmented pipe body, the length of the gas storage pipe is adjusted by changing the number of segmented pipe bodies, and N static pressure sensors are evenly installed on the gas storage pipe along the air flow direction to measure the stabilized gas pressure of the gas storage pipe.

[0013] Furthermore, a safety pressure relief valve is provided at the air inlet end of the air storage pipe to perform overpressure deflation and normal emptying of the pressure-stabilizing air in the air storage pipe and the pressure-stabilizing air cavity; a pressure fine-tuning branch is provided at the outlet end of the air storage pipe, and the pressure fine-tuning branch includes a flow regulating valve and an electromagnetic stop valve III connected in sequence through a pipeline, which is used to achieve precise adjustment of the inflation pressure of the pressure-stabilizing air in the pressure-stabilizing air cavity.

[0014] Furthermore, a high-frequency pressure sensor for stabilizing gas is arranged on the stabilizing gas cavity of the stabilizing gas cylinder, a displacement sensor is arranged on the inlet end face of the stabilizing gas cavity, and a high-frequency pressure sensor for fuel is arranged on the fuel cavity.

[0015] The design and test method of the shock tunnel engine test isobaric fuel supply system of the present invention comprises the following steps:

[0016] S10. Design and process pressure-stabilizing cylinders;

[0017] According to the engine test pressure and flow Q Requirements, determine the injection pipe diameter of the pressure-stabilizing cylinder ;

[0018] Determine the length of the pressure-stabilizing cylinder according to processing capacity L During the test, the volume flowing out of the injection port should be equal to the volume moved by the piston. Therefore, the diameter of the pressure-stabilizing cylinder is , v 0 is the sonic velocity of the injected fuel gas, v q is the design speed of the piston, , t For the test time;

[0019] S20. Design and process gas storage pipes;

[0020] Gas tube volume , v 1 is the initial volume of the stabilized gas, p 1 is the initial pressure of the stabilized gas, v b In order to stabilize the volume of the compressed gas due to the movement of the piston, p 2 To stabilize the gas pressure after the test, take , that is, the pressure decay is less than 20%; the diameter of the gas storage pipe outlet , w 1 is the molecular weight of the fuel gas, w 2 is the molecular weight of the stable pressure gas;

[0021] S30. Install and debug the fuel supply system;

[0022] Connect the valves of each gas pipeline in sequence according to the requirements of the isobaric fuel supply system for shock tunnel engine testing;

[0023] Install the fast solenoid valve in the model;

[0024] M groups of annular winding coils are wound around the outer wall of the pressure-stabilizing cylinder, and each group of annular winding coils is equipped with an independent power supply;

[0025] A set of induction coils is wrapped around the cylindrical section of the cylinder piston;

[0026] Conducted the debugging of the isobaric fuel supply system for the shock tunnel engine test and determined the power supply timing and output current of the M groups of annular winding coils of the pressure-stabilizing cylinder I 0 , electromagnetic force , after discretization, , W m For energy, z is the relative displacement between coils, M 0i ( i =1 ~M) is the mutual inductance between the induction coil and the M groups of toroidal winding coils, I i is the current of the induction coil, and the electromagnetic force F ( t ) is equal to the thrust exerted on the piston by the attenuated part of the stabilizing gas pressure, that is , p t To stabilize the gas pressure at a certain moment;

[0027] S40. Conduct shock tunnel engine tests;

[0028] Before the test, open the electromagnetic stop valve IV and the fast electromagnetic valve, use the vacuum environment in the test chamber to exhaust the air in the fuel branch and the fuel cavity, set the parameters of the control system, fill the fuel gas and pressure-stabilizing gas with the specified pressure, and wait for the shock tunnel to start;

[0029] The wind tunnel is started, and the gas storage pipe is connected to the pressure-stabilizing cylinder. The pressure-stabilizing gas is the same as the fuel pressure, and the pressure-stabilizing gas is used as the driving gas to promote the fuel injection; the trigger sensor on the shock tube sends a signal to the control system to trigger the delay device. After the trigger sensor reaches the preset delay time, the fast solenoid valve is opened to start injecting the fuel gas. At the same time, the M groups of annular winding coils are powered in groups to change the current of the winding coils, adjust the electromagnetic force on the piston, compensate for the pressure attenuation of the pressure-stabilizing gas caused by the increase in volume, and realize the isobaric injection of the fuel gas; the shock tunnel inflow reaches the model, and the shock tunnel measurement and control system obtains the test data; the shock tunnel inflow ends, the gas supply is closed, the safety pressure relief valve and the electromagnetic stop valve IV are opened, the pressure-stabilizing gas in the gas storage pipe and the fuel gas in the fuel cavity are emptied, and the test ends.

[0030] The gas distribution device of the shock wind tunnel engine test isobaric fuel supply system of the present invention is used for automatically charging and discharging pressure-stabilizing gas and fuel gas of different pressures; the pressure-stabilizing device is driven by an electromagnetic piston, and the pressure stabilization is achieved by driving the piston through the pressure-stabilizing gas and electromagnetic force compensation; the delayed trigger device is used for triggering control of the rapid electromagnetic valve of the injection port to ensure the synchronization of the shock wind tunnel flow and the fuel gas injection.

[0031] The design and test method of the shock tunnel engine test isobaric fuel supply system of the present invention adopts gas compensation and electromagnetic propulsion to perform isobaric injection of fuels of different pressures, which can provide accurate test flow, ensure the stability of the fuel equivalence ratio parameters of the test, and realize isobaric supply of engine model fuel during the test time, thereby improving the test accuracy and obtaining more effective test data. It is easy to use and has practical engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the isobaric fuel supply system for shock wave wind tunnel engine test of the present invention;

[0033] In the figure, 1. pressure-stabilizing gas source; 2. pressure-stabilizing gas shut-off main valve; 3. gas booster pump; 4. programmable pressure reducing valve; 5. electromagnetic shut-off valve I; 6. electromagnetic shut-off valve II; 7. trigger sensor; 8. solid-state relay; 9. safety pressure relief valve; 10. fast electromagnetic valve; 11. pressure-stabilizing cylinder; 12. fuel high-frequency pressure sensor; 13. fuel chamber; 14. winding coil; 15. piston; 16. induction coil; 17. pressure-stabilizing gas high-frequency pressure sensor; 18. pressure-stabilizing gas chamber; 19. pressure-stabilizing gas electromagnetic shut-off valve; 20. static pressure sensor; 21. gas storage pipe; 22. flow regulating valve; 23. electromagnetic shut-off valve III; 24. displacement sensor; 25. electromagnetic shut-off valve IV; 26. pressure gauge; 27. one-way valve; 28. fuel shut-off main valve; 29. ​​fuel intake shut-off valve; 30. filter; 31. fuel gas source; 32. test chamber; 33. model; 34. shock tube. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0035] like Figure 1 As shown, the isobaric fuel supply system for shock tunnel engine test of the present invention comprises a gas distribution device, a pressure stabilizing device and a delayed trigger device, and a control system for controlling the operation of the gas distribution device, the pressure stabilizing device and the delayed trigger device;

[0036] The gas distribution device includes a pressure-stabilizing gas branch and a fuel branch; the pressure-stabilizing gas branch delivers pressure-stabilizing gas of a preset pressure to the gas storage pipe 21 of the pressure-stabilizing device, and the inlet end of the pressure-stabilizing gas branch includes a pressure-stabilizing gas source 1 and a pressure-stabilizing gas shut-off valve 2 connected in sequence; the rear end of the pressure-stabilizing gas shut-off valve 2 is divided into a parallel pressure-reducing gas circuit and a pressure-boosting gas circuit along the air intake direction, the pressure-reducing gas circuit is connected in sequence to a program-controlled pressure-reducing valve 4 and an electromagnetic shut-off valve II 6, and the pressure-boosting gas circuit is connected in sequence to a gas booster pump 3 and an electromagnetic shut-off valve I 5; the pressure-stabilizing gas branch The outlet end is connected to the gas storage pipe 21; the fuel branch delivers fuel gas of a preset pressure to the fuel chamber 13 of the pressure-stabilizing cylinder 11 of the pressure-stabilizing device, and the fuel branch includes a fuel gas source 31, and the rear end of the fuel gas source 31 is connected to the filter 30, the fuel shut-off valve 28, the pressure gauge 26, the one-way valve 27, and the fuel intake shut-off valve 29 in sequence along the intake direction, wherein the one-way valve 27 and the fuel intake shut-off valve 29 are located in the test cabin 32, and finally connected to the fuel chamber 13 at the outlet end of the pressure-stabilizing cylinder 11;

[0037] The pressure stabilizing device comprises an air storage pipe 21 and a pressure stabilizing cylinder 11; the pressure stabilizing cylinder 11 is an electromagnetic piston driven air cylinder, the inner cavity of the pressure stabilizing cylinder 11 is divided into two sections by a piston 15, the front section is a pressure stabilizing air cavity 18 at the inlet end, and the rear section is a fuel cavity 13 at the outlet end; the outer wall surface of the cylinder body of the pressure stabilizing cylinder 11 surrounds M groups of annular winding coils 14, and each group of annular winding coils 14 is equipped with an independent power supply; the piston 15 is a T-shaped piston, the vertical section of the T-shaped piston is a piston sheet matching the cross-sectional shape of the inner cavity of the pressure stabilizing cylinder 11, and the horizontal section of the T-shaped piston is a column section, and the column section surrounds the induction coil 16; the outlet end of the air storage pipe 21 is connected to the shock wave wind tunnel test cabin 32 through a flange, and the pressure stabilizing gas electromagnetic stop valve 19 and the pressure stabilizing air cavity 18 at the inlet end of the pressure stabilizing cylinder 11 are connected in sequence through a pipeline in the test cabin 32, and the fuel cavity 13 at the outlet end of the pressure stabilizing cylinder 11 is connected to the fast electromagnetic valve 10;

[0038] The delayed trigger device includes a trigger sensor 7 installed on the shock tube 34 of the shock wind tunnel. The trigger sensor 7 is connected to the solid-state relay 8 and the fast solenoid valve 10 in sequence through the control system, and finally connected to the fuel injection module on the model 33; the trigger sensor 7 realizes the synchronization of the fuel injection on the model 33 and the shock wind tunnel flow by setting the delay time, and controls the duration of the fuel injection at the same time.

[0039] Furthermore, the gas medium of the pressure-stabilized gas source is N 2 , He or Air.

[0040] Furthermore, a drain branch is provided at the front end of the one-way valve 27 of the fuel branch, and the drain branch is provided with a connection to an electromagnetic stop valve IV25.

[0041] Furthermore, the gas storage pipe 21 is a segmented pipe body, and the length of the gas storage pipe 21 is adjusted by changing the number of segmented pipe bodies. N static pressure sensors 20 are evenly installed on the gas storage pipe 21 along the air flow direction to measure the stabilized gas pressure of the gas storage pipe 21.

[0042] Furthermore, a safety pressure relief valve 9 is provided at the air inlet end of the air storage pipe 21; a pressure fine-tuning branch is provided at the outlet end of the air storage pipe 21, and the pressure fine-tuning branch includes a flow regulating valve 22 and an electromagnetic stop valve III 23 which are sequentially connected through pipelines.

[0043] Furthermore, a high-frequency pressure sensor 17 is provided on the pressure-stabilizing air cavity 18 of the pressure-stabilizing air cylinder 11 , a displacement sensor 24 is provided on the inlet end face of the pressure-stabilizing air cavity 18 , and a high-frequency pressure sensor 12 is provided on the fuel cavity 13 .

[0044] The design and test method of the shock tunnel engine test isobaric fuel supply system of the present invention comprises the following steps:

[0045] S10. Design and processing of pressure-stabilizing cylinder 11;

[0046] According to the engine test pressure and flow Q Requirements, determine the injection pipe diameter of the pressure-stabilizing cylinder 11 ;

[0047] Determine the length of the pressure-stabilizing cylinder 11 according to the processing capacity L During the test, the volume flowing out of the injection port should be equal to the volume moved by the piston 15, so the diameter of the pressure-stabilizing cylinder 11 , v 0 is the sonic velocity of the injected fuel gas, v q is the design speed of the piston 15, , t For the test time;

[0048] S20. Design and processing of gas storage pipe 21;

[0049] Gas storage tube 21 volume , v 1 is the initial volume of the stabilized pressure gas, p 1 is the initial pressure of the stabilized gas, v b To stabilize the volume of the compressed gas due to the movement of the piston 15, p 2 To stabilize the gas pressure after the test, take , that is, the pressure decay is less than 20%; the outlet diameter of the gas storage pipe 21 , w 1is the molecular weight of the fuel gas, w 2 is the molecular weight of the stable pressure gas;

[0050] S30. Install and debug the fuel supply system;

[0051] Connect the valves of each gas pipeline in sequence according to the requirements of the isobaric fuel supply system for shock tunnel engine testing;

[0052] Install the fast solenoid valve 10 in the model 33;

[0053] M groups of annular winding coils 14 are surrounded on the outer wall of the pressure-stabilizing cylinder 11, and each group of annular winding coils 14 is equipped with an independent power supply;

[0054] A set of induction coils 16 surrounds the column section of the cylinder piston 15;

[0055] Conduct the debugging of the isobaric fuel supply system for the shock tunnel engine test and determine the power supply timing and output current of the M groups of annular winding coils 14 of the pressure-stabilizing cylinder 11 I 0 , electromagnetic force , after discretization, , W m For energy, z is the relative displacement between coils, M 0i ( i =1 ~M) is the mutual inductance between the induction coil 16 and the M groups of annular winding coils 14, I i is the current of the induction coil 16, and the electromagnetic force F ( t ) is equal to the thrust of the attenuated part of the stabilizing gas pressure on the piston 15, that is, , p t To stabilize the gas pressure at a certain moment;

[0056] S40. Conduct shock tunnel engine tests;

[0057] Before the test, open the electromagnetic stop valve IV 25 and the fast electromagnetic valve 10, use the vacuum environment in the test chamber 32 to exhaust the air in the fuel branch and the fuel chamber 13, set the parameters of the control system, fill the fuel gas and the pressure-stabilizing gas with the specified pressure, and wait for the shock tunnel to start;

[0058] The wind tunnel is started, and the gas storage pipe 21 is connected to the pressure-stabilizing cylinder 11. The pressure-stabilizing gas is the same as the fuel pressure, and the pressure-stabilizing gas is used as the driving gas to promote the fuel injection; the trigger sensor 7 on the shock tube 34 sends a signal to the control system to trigger the delay device. After the trigger sensor 7 reaches the preset delay time, the fast solenoid valve 10 is opened to start injecting the fuel gas. At the same time, the M groups of annular winding coils 14 are powered in groups, the current of the winding coils 14 is changed, the electromagnetic force on the piston 15 is adjusted, and the pressure attenuation of the pressure-stabilizing gas caused by the increase in volume is compensated, so as to realize the isobaric injection of the fuel gas; the shock tunnel inflow reaches the model 33, and the shock tunnel measurement and control system obtains the test data; the shock tunnel inflow ends, the gas supply is closed, the safety pressure relief valve 9 and the electromagnetic stop valve IV25 are opened, the pressure-stabilizing gas in the gas storage pipe 21 and the fuel gas in the fuel chamber 13 are emptied, and the test ends.

[0059] Embodiment: In this embodiment, the fuel gas pressure injected is 4.92MPa, the flow rate is 0.1kg / s, and the shock wave wind tunnel test time is 10ms. The pressure-stabilizing gas source 1 uses nitrogen directly supplied from the factory, with a pressure of 17MPa; the fuel gas source 31 is hydrogen, supplied by a gas cylinder group, with a pressure of 10MPa; the length of the pressure-stabilizing cylinder 11 is L= 400mm, cylinder diameter The injection pipe diameter is 200mm The outer wall of the pressure-stabilizing cylinder 11 is surrounded by M=4 groups of annular winding coils 14, and the piston 15 is surrounded by 1 group of induction coils 16; the gas storage pipe 21 is 14m long, with an inner diameter of 100mm, a pressure bearing capacity of 22MPa, and an outlet pipe diameter of The frequency response of the fuel high-frequency pressure sensor 12 and the stabilized gas high-frequency pressure sensor 17 are both 50kHz; the fast solenoid valve 10 is automatically triggered, and the action time from triggering to fully opening is less than 15ms.

[0060] The specific implementation steps of this embodiment are as follows:

[0061] Step 1. Process the pressure-stabilizing cylinder 11 and the gas storage pipe 21, connect the valves of each gas pipeline in sequence, install the fast solenoid valve 10 in the model 33, carry out system debugging, preliminarily set the timing and current parameters of the M group of annular winding coils 14 so that the electromagnetic force increases linearly, and then make further corrections through the measured values ​​of the pressure-stabilizing gas high-frequency pressure sensor 17 and the displacement sensor 24;

[0062] Step 2. Before the test, open the electromagnetic stop valve IV25 and the fast electromagnetic valve 10, use the vacuum environment in the test chamber 32 to exhaust the air in the fuel branch and the fuel chamber 13, set the control system parameters, fill with 4.92MPa hydrogen fuel and nitrogen pressure-stabilizing gas, and wait for the shock tunnel to start;

[0063] Step 3. The wind tunnel is started, the shock tube 34 breaks the membrane, the trigger sensor 7 sends a signal to the control system to trigger the delay device, and the fast solenoid valve 10 is opened after a delay of 100ms, and the fuel gas begins to be injected. The M groups of annular winding coils 14 are grouped to supply power to compensate for the attenuation pressure of the pressure-stabilizing gas; the shock tunnel flow reaches the model 33, and the shock tunnel measurement and control system obtains the test data;

[0064] Step 4. After the fuel gas injection lasts for 150ms, the shock tunnel flow ends, the supply of the pressure-stabilizing gas source 1 and the fuel gas source 31 is closed, the safety pressure relief valve 9 and the electromagnetic shut-off valve IV25 are opened, the pressure-stabilizing gas in the gas storage pipe 21 and the fuel gas in the fuel chamber 13 are emptied, and the test ends.

[0065] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. For those familiar with the art, all features disclosed in the present invention, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. Isobaric fuel supply system for shock wave wind tunnel engine test, characterized in that: The shock wave wind tunnel engine test isobaric fuel supply system comprises a gas distribution device, a pressure stabilizing device and a delayed trigger device, and a control system for controlling the operation of the gas distribution device, the pressure stabilizing device and the delayed trigger device; The gas distribution device comprises a pressure-stabilizing gas branch and a fuel branch; the pressure-stabilizing gas branch delivers pressure-stabilizing gas of a preset pressure to a gas storage pipe (21) of the pressure-stabilizing device, and the inlet end of the pressure-stabilizing gas branch comprises a pressure-stabilizing gas source (1) and a pressure-stabilizing gas shut-off valve (2) connected in sequence; the rear end of the pressure-stabilizing gas shut-off valve (2) is divided into a pressure-reducing gas path and a pressure-boosting gas path connected in parallel along the air intake direction, the pressure-reducing gas path is connected in sequence to a programmable pressure-reducing valve (4) and an electromagnetic shut-off valve II (6), and the pressure-boosting gas path is connected in sequence to a gas boosting pump (3) and an electromagnetic shut-off valve I (5); the outlet end of the pressure-stabilizing gas branch is connected to a gas storage pipe (21) and a fuel storage pipe (2 ... The fuel branch conveys fuel gas of a preset pressure to the fuel chamber (13) of the pressure stabilizing cylinder (11) of the pressure stabilizing device, the fuel branch comprising a fuel gas source (31), the rear end of the fuel gas source (31) being connected in sequence along the air intake direction to a filter (30), a fuel shut-off valve (28), a pressure gauge (26), a one-way valve (27), and a fuel air intake shut-off valve (29), wherein the one-way valve (27) and the fuel air intake shut-off valve (29) are located in the test chamber (32), and finally connected to the fuel chamber (13) at the outlet end of the pressure stabilizing cylinder (11); The pressure stabilizing device comprises an air storage pipe (21) and a pressure stabilizing cylinder (11); the pressure stabilizing cylinder (11) is an electromagnetic piston driven cylinder, the inner cavity of the pressure stabilizing cylinder (11) is divided into two sections by a piston (15), the front section is a pressure stabilizing air cavity (18) at the inlet end, and the rear section is a fuel cavity (13) at the outlet end; the outer wall surface of the cylinder body of the pressure stabilizing cylinder (11) surrounds M groups of annular winding coils (14), and each group of annular winding coils (14) is equipped with an independent power supply; the piston (15) is a T-shaped piston, and the T-shaped piston The vertical section is a piston plate that matches the cross-sectional shape of the inner cavity of the pressure-stabilizing cylinder (11); the horizontal section of the T-shaped piston is a column section, and the column section is surrounded by an induction coil (16); the outlet end of the gas storage pipe (21) is connected to the shock wave wind tunnel test cabin (32) through a flange, and the pressure-stabilizing gas electromagnetic stop valve (19) and the pressure-stabilizing gas cavity (18) at the inlet end of the pressure-stabilizing cylinder (11) are connected in sequence through a pipeline in the test cabin (32); the fuel cavity (13) at the outlet end of the pressure-stabilizing cylinder (11) is connected to the fast electromagnetic valve (10); The delayed trigger device comprises a trigger sensor (7) installed on a shock tube (34) of a shock wind tunnel. The trigger sensor (7) is sequentially connected to a solid-state relay (8) and a fast solenoid valve (10) through a control system, and finally connected to a fuel injection module on a model (33). The trigger sensor (7) achieves synchronization of fuel injection on the model (33) with the shock wind tunnel flow by setting a delay time, and controls the duration of fuel injection at the same time.

2. The shock wave wind tunnel engine test isobaric fuel supply system according to claim 1, characterized in that: The gas medium of the pressure-stabilized gas source (1) is N2, He or Air.

3. The shock wave wind tunnel engine test isobaric fuel supply system according to claim 1, characterized in that: A drain branch is provided at the front end of the one-way valve (27) of the fuel branch, and the drain branch is provided with a solenoid stop valve IV (25) for connection.

4. The shock wave wind tunnel engine test isobaric fuel supply system according to claim 1, characterized in that: The gas storage pipe (21) is a segmented pipe body, and the length of the gas storage pipe (21) is adjusted by changing the number of segmented pipe bodies. N static pressure sensors (20) are evenly installed on the gas storage pipe (21) along the air flow direction to measure the stabilized gas pressure of the gas storage pipe (21).

5. The shock wave wind tunnel engine test isobaric fuel supply system according to claim 1, characterized in that: A safety pressure relief valve (9) is provided at the air inlet end of the air storage pipe (21); a pressure fine-tuning branch is provided at the outlet end of the air storage pipe (21), and the pressure fine-tuning branch comprises a flow regulating valve (22) and an electromagnetic stop valve III (23) which are connected in sequence through a pipeline.

6. The shock wave wind tunnel engine test isobaric fuel supply system according to claim 1, characterized in that: A high-frequency pressure sensor (17) for stabilizing air is arranged on the stabilizing air cavity (18) of the stabilizing air cylinder (11), a displacement sensor (24) is arranged on the inlet end surface of the stabilizing air cavity (18), and a high-frequency pressure sensor (12) for fuel is arranged on the fuel cavity (13).

7. Design and test method of an isobaric fuel supply system for shock wind tunnel engine tests, which is used in the isobaric fuel supply system for shock wind tunnel engine tests as described in any one of claims 1 to 6, characterized in that: The following steps are involved: S10. Design and process the pressure-stabilizing cylinder (11); According to the engine test pressure and flow Q Requirements, determine the injection pipe diameter of the pressure-stabilizing cylinder (11) ; Determine the length of the pressure-stabilizing cylinder (11) according to the processing capacity L During the test, the volume flowing out of the injection port should be equal to the volume moved by the piston (15). Therefore, the diameter of the pressure-stabilizing cylinder (11) , v 0 is the sonic velocity of the injected fuel gas, v q is the design speed of the piston (15), , t For the test time; S20. Design and process the gas storage pipe (21); Volume of gas storage tube (21) , v 1 is the initial volume of the pressure-stabilizing gas, p 1 is the initial pressure of the stabilized gas, v b To stabilize the volume of the compressed gas due to the movement of the piston (15), p 2 is the stabilized gas pressure after the test, , that is, the pressure decay is less than 20%; the outlet pipe diameter of the gas storage pipe (21) , w 1 is the molecular weight of fuel gas, w 2 is the molecular weight of the pressure-stabilizing gas; S30. Install and debug the fuel supply system; Connect the valves of each gas pipeline in sequence according to the requirements of the isobaric fuel supply system for shock tunnel engine testing; Install the fast solenoid valve (10) in the model (33); M groups of annular winding coils (14) are surrounded on the outer wall of the pressure-stabilizing cylinder (11), and each group of annular winding coils (14) is equipped with an independent power supply; A set of induction coils (16) are wrapped around the column section of the cylinder piston (15); Conduct the debugging of the isobaric fuel supply system for the shock tunnel engine test and determine the power supply timing and output current of the M groups of annular winding coils (14) of the pressure-stabilizing cylinder (11) I 0, electromagnetic force , M 0i ( i =1 ~M) is the mutual inductance between the induction coil (16) and the M groups of annular winding coils (14), I i is the current of the induction coil (16), is the relative displacement between coils, and the electromagnetic force F ( t ) is equal to the thrust exerted on the piston (15) by the attenuated portion of the stabilizing gas pressure, that is, , p t To stabilize the gas pressure at a certain moment; S40. Conduct shock tunnel engine tests; Before the test, the electromagnetic stop valve IV (25) and the fast electromagnetic valve (10) are opened, the air in the fuel branch and the fuel chamber (13) is exhausted by utilizing the vacuum environment in the test chamber (32), the control system sets parameters, the fuel gas and the pressure-stabilizing gas of the specified pressure are filled, and the shock tunnel is waited for to be started; The wind tunnel is started, the gas storage pipe (21) is connected to the pressure-stabilizing cylinder (11), the pressure-stabilizing gas is the same as the fuel pressure, and the pressure-stabilizing gas is used as the driving gas to promote the fuel injection; the trigger sensor (7) on the shock tube (34) sends a signal to the control system to trigger the delay device, and after the trigger sensor (7) reaches the preset delay time, the fast electromagnetic valve (10) is opened to start the injection of fuel gas. At the same time, the M groups of annular winding coils (14) are grouped for power supply, the current size of the winding coils (14) is changed, the electromagnetic force on the piston (15) is adjusted, and the pressure attenuation caused by the increase in volume of the pressure-stabilizing gas is compensated, so as to achieve isobaric injection of fuel gas; the shock tunnel inflow reaches the model (33), and the shock tunnel measurement and control system obtains the test data; the shock tunnel inflow ends, the gas source supply is closed, the safety pressure relief valve (9) and the electromagnetic stop valve IV (25) are opened, the pressure-stabilizing gas in the gas storage pipe (21) and the fuel gas in the fuel chamber (13) are emptied, and the test ends.

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