Aircraft engine test bench fuel system

Abstract

The present invention discloses a fuel system for an aircraft engine test bench, comprising an open fuel tank, a closed fuel tank, an oil inlet pipeline, a pressure-boosting pipeline, an oil supply pipeline, an oil return pipeline, a pressure-stabilizing pipeline and a control system. The oil supply pipeline is provided with a fire damper, and the fire damper is provided with a drainage pipeline for preventing pressure buildup in the oil supply pipeline. The oil return pipeline is provided with an equivalent nozzle and a radiator. The oil outlet of the equivalent nozzle, the oil inlet of the radiator and the drainage pipeline on the fire damper are connected to each other. The control system is used to control the on-off of the oil inlet pipeline, the pressure-boosting pipeline, the oil supply pipeline and the oil return pipeline. The fuel system of the aircraft engine test bench can not only prevent the high-pressure and ultra-large-flow dynamic flow oil return pipeline of the engine from directly impacting instruments and meters on the oil supply pipeline, but also eliminate the safety hazards caused by gas leakage, and discharge the oil supply pressure fluctuation caused by external interference, thereby ensuring the smooth progress of the test.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation engines, and in particular to a fuel system of an aviation engine test bench. Background Art

[0002] Aircraft engine development is inseparable from ground-based full-machine test bench testing and verification. The "General Specification for Aviation Turboprop and Turboshaft Engines" (GJB242A) stipulates that engine development and certification require tens of thousands of hours of full-machine testing, including endurance testing, environmental testing, and swallowing tests. Because full-machine aircraft engine testing consumes nearly 10,000 tons of fuel, the test bench's fuel is generally sourced from a centrally managed fuel depot within the test area.

[0003] During the test run of a newly developed high-power aviation turboprop engine, part of the fuel entering the engine enters the combustion chamber to perform work, and the remaining unburned fuel returns to the dynamic flow return oil pipeline of the test bench fuel system. The dynamic flow return oil flow rate of the dynamic flow return oil pipeline is greater than 1500kg / h, the dynamic flow return oil pipeline outlet pressure is greater than 10MPa, and the maximum fuel temperature at the dynamic flow return oil pipeline outlet is higher than 100℃.

[0004] The existing test bench fuel system only requires low-pressure, low-flow dynamic return oil. Typically, the dynamic return oil pipe is directly connected to the oil pipeline from the oil depot for circulating oil supply. Testing this type of engine with the existing test bench fuel system will cause the following problems in both the test bench fuel system and the engine fuel system:

[0005] First, directly connecting the high-pressure, high-flow dynamic return oil pipe to the oil depot's oil pipeline can easily cause fuel leakage at weak seals in the test bench's fuel system pipelines and instrumentation, posing a safety hazard such as fire or explosion at the test site. Furthermore, the high-pressure fuel can impact the test bench's fuel system instruments and equipment, easily causing damage to the fuel system. It can also cause the engine's fuel inlet pressure to significantly exceed the limit, leading to damage to the engine's fuel components and even the engine.

[0006] Second, aircraft engine ground test benches within the same plant are built in a centralized, side-by-side manner. All test benches use fuel from the same oil depot. The pressure of the fuel directly supplied from the depot is easily affected by other test benches and fluctuates, causing fluctuations in the engine fuel inlet pressure and resulting in unstable engine operation.

[0007] 3. The existing fuel system fire damper is only used to turn fuel on and off. After closing the fire damper, the front section of the fuel supply pipeline is pressurized, which can easily lead to fuel leakage and cause safety accidents. Summary of the Invention

[0008] The present invention provides an aviation engine test bench fuel system to solve the technical problem that the existing aviation engine test bench fuel system is difficult to meet the use requirements of a certain type of high-power aviation turboprop engine test.

[0009] According to one aspect of the present invention, a fuel system for an aircraft engine test bench is provided, comprising an open fuel tank, a closed fuel tank, an oil inlet pipeline connecting the open fuel tank with oil from a tank depot, a boost pipeline for connecting the open fuel tank and the closed fuel tank, an oil supply pipeline for connecting the closed fuel tank and an engine, an oil return pipeline for connecting the engine and the open fuel tank, a pressure-stabilizing pipeline for maintaining a preset pressure in the closed fuel tank, and a control system, wherein a fire damper is arranged on the oil supply pipeline, the fire damper is provided with a drainage pipeline for preventing pressure buildup in the oil supply pipeline, an equivalent nozzle and a radiator are arranged on the oil return pipeline, the oil outlet of the equivalent nozzle, the oil inlet of the radiator and the drainage pipeline on the fire damper are connected to each other, and the control system is used to control the on-off of the oil inlet pipeline, the boost pipeline, the oil supply pipeline and the oil return pipeline.

[0010] Furthermore, the air inlet end of the pressure-stabilizing pipeline is used to be connected to the air source, and the air outlet end of the pressure-stabilizing pipeline is connected to the air inlet arranged at the top of the closed oil tank. The pressure-stabilizing pipeline is sequentially provided with a first on-off valve for controlling the on and off of the pressure-stabilizing pipeline, a water filter for filtering moisture in the air flow, an oil filter for filtering oil mist in the air flow, a pressure reducing valve for controlling the air flow pressure at the air outlet end of the pressure-stabilizing pipeline, and a first one-way valve for preventing the air flow from flowing back to the pressure reducing valve. The outlet of the first one-way valve is connected to the air inlet of the closed oil tank, and the pressure reducing valve is connected to the control system.

[0011] Furthermore, a back-pressure branch is connected to the pressure-stabilizing pipeline, and the air inlet of the back-pressure branch, the outlet of the first one-way valve, and the air inlet of the closed fuel tank are connected to each other. A back-pressure valve for adjusting the pressure in the closed fuel tank and a first oil-gas separator for preventing the fuel in the closed fuel tank from atomizing and leaking into the atmosphere are arranged on the back-pressure branch, and the back-pressure valve is connected to the control system.

[0012] Furthermore, the flow rate range of the equivalent nozzle is 1200~2200kg / h, and a throat is arranged inside the equivalent nozzle, and the throat is used to ensure that the pressure difference between the inlet end of the equivalent nozzle and the engine dynamic flow return oil outlet is less than 0.5MPa.

[0013] Furthermore, the oil inlet pipeline is provided with a second on-off valve for controlling the on-off of the oil inlet pipeline and a first oil filter for filtering the fuel. The open fuel tank is provided with a first liquid level gauge. The first liquid level gauge and the second on-off valve are both connected to the control system. The first liquid level gauge is used to feed back the liquid level information in the open fuel tank to the control system. The control system controls the on-off of the second on-off valve according to the liquid level information in the open fuel tank.

[0014] Furthermore, the boost pipeline is provided with a boost pump for pressurizing the fuel in the open fuel tank to inject it into the closed fuel tank and a second one-way valve for preventing the fuel from flowing back to the open fuel tank. The boost pump is connected to the control system. A second liquid level gauge is provided on the closed fuel tank, and the second liquid level gauge is connected to the control system. The second liquid level gauge is used to feed back liquid level information in the closed fuel tank to the control system. The control system controls the start and stop of the boost pump according to the liquid level information in the closed fuel tank.

[0015] Furthermore, the oil supply pipeline is provided with a third one-way valve for preventing the fuel from flowing back to the closed oil tank, the oil return pipeline is provided with a fourth one-way valve for preventing the fuel from flowing back to the outlet of the equivalent nozzle, and a third on-off valve for controlling the on-off of the oil return pipeline, and the third on-off valve is connected to the control system.

[0016] Furthermore, a pressure gauge, a temperature gauge and a flow meter are arranged on the oil supply pipeline and / or the oil return pipeline.

[0017] Furthermore, a fourth on-off valve and an emergency branch for bypassing the flow meter are respectively arranged at both ends of the flow meter, and a fifth on-off valve is arranged on the emergency branch.

[0018] Furthermore, the open fuel tank is provided with a second oil-gas separator for preventing fuel atomization from leaking into the atmosphere, and the closed fuel tank is provided with a safety valve and / or overflow valve for pressure relief.

[0019] The present invention has the following beneficial effects:

[0020] The aviation engine test bench fuel system of the present invention is transitioned through an open fuel tank and the fuel supply pressure of the closed fuel tank is ensured by a pressure-stabilizing pipeline. It can not only avoid the engine's high-pressure, ultra-large flow dynamic flow return pipe from directly impacting the instruments on the fuel supply pipeline, but also eliminate the safety hazards caused by gas leakage, and discharge the fuel supply pressure fluctuations caused by external interference, ensuring the smooth progress of the test. The pressure difference between the inlet end of the equivalent nozzle and the engine dynamic flow return oil outlet is stabilized by the equivalent nozzle, which can not only ensure the normal operation of the engine, but also allow the return fuel to flow smoothly back to the open fuel tank. The fire damper is connected to the return oil pipeline through the dredging oil path, which can avoid pressure buildup in the front section of the oil inlet pipeline when the fire damper is closed, reducing the risk of fuel leakage. It is not only suitable for high-power turboprop engine tests with high-pressure and ultra-large flow dynamic flow return oil, but can also be applied to low-pressure and small flow dynamic flow return oil engine tests after replacing or removing the equivalent nozzle on the dynamic return oil pipeline.

[0021] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 This is a schematic structural diagram of an aircraft engine test bench fuel system according to a preferred embodiment of the present invention;

[0024] Figure 2 It is a structural schematic diagram of an equivalent nozzle according to a preferred embodiment of the present invention.

[0025] Legend:

[0026] 1. Open fuel tank; 11. First level gauge; 12. Second oil-gas separator; 13. Third level gauge; 2. Closed fuel tank; 21. Second level gauge; 22. Safety valve; 23. Overflow valve; 3. Engine; 4. Fuel inlet line; 41. Second on-off valve; 42. First oil filter; 5. Booster line; 51. Booster pump; 52. Second check valve; 6. Fuel supply line; 61. Fire damper; 62. Drain line; 63. Fourth on-off valve; 64. Emergency branch line; 65. Fifth on-off valve ; 66. Third one-way valve; 67. Second oil filter; 7. Oil return line; 71. Equivalent nozzle; 711. Throat; 72. Radiator; 73. Fourth one-way valve; 74. Pressure gauge; 75. Thermometer; 76. Turbine flowmeter; 77. Mass flowmeter; 78. Third on-off valve; 8. Pressure-stabilizing line; 81. First on-off valve; 82. Water filter; 83. Oil filter; 84. Pressure reducing valve; 85. First one-way valve; 86. Back-pressure branch; 87. Back-pressure valve; 88. First oil-gas separator. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0028] like Figure 1 As shown, the fuel system of the aircraft engine test bench of this embodiment includes an open fuel tank 1, a closed fuel tank 2, an oil inlet pipeline 4 connecting the open fuel tank 1 with the oil from the oil depot, a booster pipeline 5 for connecting the open fuel tank 1 and the closed fuel tank 2, an oil supply pipeline 6 for connecting the closed fuel tank 2 and the engine 3, an oil return pipeline 7 for connecting the engine 3 and the open fuel tank 1, a pressure stabilizing pipeline 8 for maintaining a preset pressure in the closed fuel tank 2, and a control system. A fire damper is arranged on the fuel supply pipeline 6. 61. The fire damper 61 is provided with a drainage pipe 62 for preventing pressure buildup in the oil supply pipe 6. The return oil pipe 7 is provided with an equivalent nozzle 71 for stabilizing the pressure difference between the inlet end of the equivalent nozzle 71 and the outlet of the dynamic flow return oil of the engine 3, and a radiator 72 for cooling the dynamic flow return oil. The oil outlet of the equivalent nozzle 71, the oil inlet of the radiator 72 and the drainage pipe 62 on the fire damper 61 are interconnected. The control system is used to control the on-off of the oil inlet pipe 4, the boost pipe 5, the oil supply pipe 6 and the oil return pipe 7.

[0029] The aircraft engine test bench fuel system of this embodiment uses an open fuel tank 1 for transition and a pressure-stabilizing line 8 to ensure the fuel supply pressure of the closed fuel tank 2. This system can prevent the high-pressure, ultra-large-flow dynamic return oil pipe of the engine 3 from directly impacting the instruments on the fuel supply line 6, eliminate the safety hazards caused by gas leakage, and eliminate the fuel supply pressure fluctuations caused by external interference, ensuring the smooth progress of the test. The pressure difference between the inlet end of the equivalent nozzle 71 and the dynamic return oil outlet of the engine 3 is stabilized by the equivalent nozzle 71, which can ensure the normal operation of the engine 3 and allow the return fuel to flow smoothly back to the open fuel tank 1. The fire damper 61 is connected to the return oil line 7 through the drainage line 62, which can avoid pressure buildup in the front section of the fuel inlet line 4 when the fire damper 61 is closed, thereby reducing the risk of fuel leakage. The system is not only suitable for testing high-power turboprop engines with high-pressure, ultra-large-flow dynamic return oil, but can also be used for testing low-pressure, small-flow dynamic return oil engines by replacing or removing the equivalent nozzle 71 on the dynamic return oil line 7. Optionally, a second oil filter 67 for filtering the fuel is provided on the oil supply line 6 to ensure the fuel is clean and avoid damage to the engine 3 .

[0030] Optionally, a third level gauge 13 is provided on the open fuel tank 1 and / or the closed fuel tank 2 for on-site visual inspection. Optionally, a third on-off valve 78 is provided on the oil return line 7 to control the on / off operation of the oil return line 7. This third on-off valve 78 is connected to the control system. Closing this valve allows the test bench fuel system to be used for non-dynamic return oil engine testing, broadening its applicability. Optionally, this third on-off valve 78 is a solenoid valve or pneumatic valve, enabling test participants to remotely control its on / off operation from the operator's booth.

[0031] In this embodiment, the air inlet end of the pressure-stabilizing pipeline 8 is used to be connected to the air source, and the air outlet end of the pressure-stabilizing pipeline 8 is connected to the air inlet arranged at the top of the closed fuel tank 2. The pressure-stabilizing pipeline 8 is sequentially provided with a first on-off valve 81 for controlling the on and off of the pressure-stabilizing pipeline 8, a water filter 82 for filtering moisture in the air flow, an oil filter 83 for filtering oil mist in the air flow, a pressure reducing valve 84 for controlling the air flow pressure at the air outlet end of the pressure-stabilizing pipeline 8, and a first one-way valve 85 for preventing the air flow from flowing back to the pressure reducing valve 84. The outlet of the first one-way valve 85 is connected to the air inlet of the closed fuel tank 2, and the pressure reducing valve 84 is connected to the control system; the air flow supplied by the air source passes through the first on-off valve 81, the water filter 82, the oil filter 83, the pressure reducing valve 84, and the first one-way valve 85 and then enters the closed fuel tank 2, ensuring that the fuel supply pressure of the closed fuel tank 2 to the engine 3 will not be affected by other factors and cause fuel pressure fluctuations, thereby ensuring stable operation of the engine 3.

[0032] In this embodiment, a back-pressure branch 86 is connected to the pressure-stabilizing pipeline 8, and the air inlet of the back-pressure branch 86, the outlet of the first one-way valve 85, and the air inlet of the closed fuel tank 2 are connected to each other. A back-pressure valve 87 for adjusting the pressure in the closed fuel tank 2 and a first oil-gas separator 88 for preventing the fuel in the closed fuel tank 2 from atomizing and leaking into the atmosphere are arranged on the back-pressure branch 86. The back-pressure valve 87 is connected to the control system; by adjusting the preset pressure values ​​of the pressure reducing valve 84 and the back-pressure valve 87, the fuel supply pressure of the aircraft fuel tank can be accurately simulated to ensure the accuracy of the test.

[0033] like Figure 2 As shown, in this embodiment, the flow range of the equivalent nozzle 71 is 1200~2200 kg / h, and a throat 711 is arranged in the equivalent nozzle 71. The throat 711 is used to ensure that the pressure difference between the inlet end of the equivalent nozzle 71 and the dynamic flow return oil outlet of the engine 3 is less than 0.5 MPa; the equivalent nozzle 71 is used to maintain the pressure stability of the fuel from the dynamic flow return oil outlet of the engine 3 to the front end of the equivalent nozzle 71. If the equivalent nozzle 71 is not provided, the dynamic flow return oil outlet pressure of the engine 3 will instantly drop from an ultra-high pressure of more than 10 MPa to a conventional pressure range of less than 1 MPa. The pressure difference is very large. When the operating state of the engine 3 changes, it will cause large fluctuations in the fuel supply flow and pressure of the engine 3, thereby leading to a series of problems and hidden dangers such as unstable output power of the engine 3, overheating of the lubricating oil, and excessive vibration. A throat 711 is provided within the stoichiometric nozzle 71. If the flow rate of the stoichiometric nozzle 71 is less than 1200 kg / h, the pressure difference in the connecting pipeline between the front end of the stoichiometric nozzle 71 of the test bench fuel system and the dynamic flow return oil outlet of the engine 3 will be greater than 0.5 MPa, affecting the stability of the fuel supply to the engine 3. If the flow rate of the equivalent nozzle 71 is greater than 2200 kg / h, the dynamic flow return oil pressure will increase due to poor circulation, causing abnormal phenomena such as fuel overflow and leakage, and in severe cases, leading to a fire at the test site; therefore, the flow rate range of the equivalent nozzle 71 is 1200~2200 kg / h, which can not only ensure that the pressure difference of the connecting pipeline between the front end of the equivalent nozzle 71 of the test bench fuel system and the dynamic flow return oil outlet of the engine 3 is less than 0.5MPa, but also ensure the smoothness of the dynamic flow return oil. Under the dynamic flow return condition of ultra-large flow, abnormal phenomena such as increased dynamic flow return oil pressure due to poor circulation will not occur. At the same time, it can also ensure that there is a certain low pressure from the equivalent nozzle 71 to the open fuel tank 1, and the return fuel can flow smoothly back to the open fuel tank 1.

[0034] In this embodiment, the oil inlet pipeline 4 is provided with a second on-off valve 41 for controlling the on-off of the oil inlet pipeline 4 and a first oil filter 42 for filtering the fuel. The open fuel tank 1 is provided with a first liquid level gauge 11. The first liquid level gauge 11 and the second on-off valve 41 are both connected to the control system. The first liquid level gauge 11 is used to feed back the liquid level information in the open fuel tank 1 to the control system. The control system controls the on-off of the second on-off valve 41 according to the liquid level information in the open fuel tank 1. The oil from the oil depot passes through the second on-off valve 41 and the first oil filter 42 on the oil inlet pipeline 4. Entering the open fuel tank 1, the first liquid level gauge 11 and the second on-off valve 41 on the open fuel tank 1 are connected to the control system, and the fuel level signal of the open fuel tank 1 is displayed in real time on the screen in the operator's room through the digital acquisition system. When the liquid level of the open fuel tank 1 is lower than the minimum liquid level, the second on-off valve 41 is opened to replenish the open fuel tank 1, and the oil from the oil tank enters the open fuel tank 1; when the liquid level of the open fuel tank 1 reaches the set high liquid level, the second on-off valve 41 is closed to stop replenishing the open fuel tank 1, with a high degree of automation.

[0035] In this embodiment, a boosting pump 51 for boosting the fuel in the open fuel tank 1 to inject it into the closed fuel tank 2 and a second one-way valve 52 for preventing the fuel from flowing back to the open fuel tank 1 are arranged on the boosting pipeline 5. The boosting pump 51 is connected to the control system. A second liquid level gauge 21 is arranged on the closed fuel tank 2. The second liquid level gauge 21 is connected to the control system. The second liquid level gauge 21 is used to feed back the liquid level information in the closed fuel tank 2 to the control system. The control system controls the start and stop of the boosting pump 51 according to the liquid level information in the closed fuel tank 2. The fuel in the open fuel tank 1 flows to the closed fuel tank 2 through the boosting pump 51 and the second one-way valve 52 on the boosting pipeline 5. The second level gauge 21 and booster pump 51 on the closed fuel tank 2 are connected to the control system. The fuel level signal of the closed fuel tank 2 is displayed in real time on the screen in the test operator's control room via the data acquisition system. When the fuel level in the closed fuel tank 2 monitored by the second level gauge 21 falls below the minimum level, the booster pump 51 is activated to replenish the closed fuel tank 2, and the fuel in the open fuel tank 1 enters the closed fuel tank 2. When the fuel level in the closed fuel tank 2 monitored by the second level gauge 21 reaches the set high level, the booster pump 51 is shut down to stop replenishing the closed fuel tank 2. This allows test operators to remotely monitor the fuel level and automatically replenish the fuel in the test operation room. Optionally, the closed fuel tank 2 is equipped with an emergency fuel supply capacity of no less than 100L. If the booster line 5 malfunctions (second level gauge 21 malfunctions or booster pump 51 malfunctions), an alarm is issued when the fuel level in the closed fuel tank 2 reaches a low level, and the test bench fuel system enters an emergency fuel supply state.

[0036] In this embodiment, a third one-way valve 66 is provided on the oil supply line 6 for preventing the fuel from flowing back to the closed oil tank 2, a fourth one-way valve 73 is provided on the oil return line 7 for preventing the fuel from flowing back to the outlet of the equivalent nozzle 71, and a third on-off valve 78 is provided on the oil return line 7 for controlling the on-off of the oil return line 7. The third on-off valve 78 is connected to the control system.

[0037] In this embodiment, the oil supply pipeline 6 is provided with a pressure gauge 74 for monitoring the fuel pressure on the oil supply pipeline 6, a thermometer 75 for monitoring the fuel temperature on the oil supply pipeline 6, and a turbine flowmeter 76 and / or a mass flowmeter 77 for monitoring the fuel flow on the oil supply pipeline 6; the return oil pipeline 7 is provided with a pressure gauge 74 for monitoring the fuel pressure on the return oil pipeline 7, a thermometer 75 for monitoring the fuel temperature on the return oil pipeline 7, and a turbine flowmeter 76 and / or a mass flowmeter 77 for monitoring the fuel flow on the return oil pipeline 7. The pressure gauge 74, the thermometer 75, the turbine flowmeter 76 and / or the mass flowmeter 77 are all connected to the control system, and the collected data are displayed in real time on the screen in the control room.

[0038] In this embodiment, a fourth on-off valve 63 and an emergency branch 64 for bypassing the flowmeter are disposed at each end of the turbine flowmeter 76. The emergency branch 64 is provided with a fifth on-off valve 65. The emergency branch 64 is used for maintenance and emergency situations of the turbine flowmeter 76. If the turbine flowmeter 76 requires maintenance or an emergency situation (such as communication interruption or jamming) occurs, the fifth on-off valve 65 on the emergency branch 64 is first opened, and then the fourth on-off valves 63 at both ends of the turbine flowmeter 76 are closed. The oil system can continue to flow oil and operate. After maintenance is completed or the emergency situation is resolved, the fourth on-off valves 63 at both ends of the turbine flowmeter 76 are first opened, and then the fifth on-off valve 65 on the emergency branch 64 is closed, restoring normal operation. A fourth on-off valve 63 and an emergency branch 64 for bypassing the flowmeter are respectively arranged at both ends of the mass flowmeter 77, and a fifth on-off valve 65 is arranged on the emergency branch 64. Similarly, if the mass flowmeter 77 is under maintenance or an emergency situation occurs (communication interruption, jamming, etc.), the fifth on-off valve 65 on the emergency branch 64 is opened first, and then the fourth on-off valve 63 at both ends of the mass flowmeter 77 is closed. The oil circuit system can still flow oil and continue to operate. After the maintenance is completed or the emergency situation is lifted, the fourth on-off valve 63 at both ends of the mass flowmeter 77 is opened first, and then the fifth on-off valve 65 on the emergency branch 64 is opened to restore normal operation. Optionally, the fourth on-off valve 63 and the fifth on-off valve 65 are solenoid valves or pneumatic valves with a high degree of automation, and test personnel can complete the control operation in the operating room. It is understood that the fourth on-off valve 63 and the fifth on-off valve 65 can also be manual valves with low cost.

[0039] In this embodiment, a second oil-gas separator 12 is provided on the open fuel tank 1 to prevent the fuel from atomizing and leaking into the atmosphere. On the one hand, this avoids fuel waste, and on the other hand, it eliminates the safety hazards of fire and explosion at the test site. A safety valve 22 and / or an overflow valve 23 for pressure relief is provided on the closed fuel tank 2. When the pressure in the closed fuel tank 2 is too high, the safety valve 22 and / or the overflow valve 23 are used to release the pressure urgently to ensure the normal operation of the test bench fuel system.

[0040] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An aircraft engine test bench fuel system, characterized in that: The invention comprises an open fuel tank (1), a closed fuel tank (2), an oil inlet pipeline (4) connecting the open fuel tank (1) and oil from a fuel depot, a pressurizing pipeline (5) for connecting the open fuel tank (1) and the closed fuel tank (2), an oil supply pipeline (6) for connecting the closed fuel tank (2) and an engine (3), an oil return pipeline (7) for connecting the engine (3) and the open fuel tank (1), a pressure stabilizing pipeline (8) for maintaining a preset pressure in the closed fuel tank (2), and a control system, wherein the oil supply pipeline (6) A fire damper (61) is arranged on the fire damper (61), and a drainage pipe (62) is arranged on the fire damper (61) for preventing the oil supply pipe (6) from being pressurized. An equivalent nozzle (71) and a radiator (72) are arranged on the oil return pipe (7). The oil outlet of the equivalent nozzle (71), the oil inlet of the radiator (72) and the drainage pipe (62) on the fire damper (61) are connected to each other. The control system is used to control the on-off of the oil inlet pipe (4), the boost pipe (5), the oil supply pipe (6) and the oil return pipe (7).

2. The aircraft engine test bench fuel system according to claim 1, characterized in that: The air inlet end of the pressure-stabilizing pipeline (8) is used to be connected to an air source, and the air outlet end of the pressure-stabilizing pipeline (8) is connected to an air inlet arranged at the top end of the closed oil tank (2). The pressure-stabilizing pipeline (8) is provided with a first on-off valve (81) for controlling the on-off of the pressure-stabilizing pipeline (8), a water filter (82) for filtering moisture in the air flow, an oil filter (83) for filtering oil mist in the air flow, a pressure reducing valve (84) for controlling the air flow pressure at the air outlet end of the pressure-stabilizing pipeline (8), and a first one-way valve (85) for preventing the air flow from flowing back to the pressure reducing valve (84). The outlet of the first one-way valve (85) is connected to the air inlet of the closed oil tank (2), and the pressure reducing valve (84) is connected to the control system.

3. The aircraft engine test bench fuel system according to claim 2, characterized in that: The pressure stabilizing pipeline (8) is connected to a back-pressure branch (86); an air inlet of the back-pressure branch (86), an outlet of the first one-way valve (85), and an air inlet of the closed fuel tank (2) are connected to each other; a back-pressure valve (87) for adjusting the pressure in the closed fuel tank (2) and a first oil-gas separator (88) for preventing the fuel in the closed fuel tank (2) from atomizing and leaking into the atmosphere are arranged on the back-pressure branch (86); and the back-pressure valve (87) is connected to the control system.

4. The aircraft engine test bench fuel system according to any one of claims 1 to 3, characterized in that: The flow rate range of the equivalent nozzle (71) is 1200-2200 kg / h. A throat (711) is provided inside the equivalent nozzle (71). The throat (711) is used to ensure that the pressure difference between the inlet end of the equivalent nozzle (71) and the dynamic flow return oil outlet of the engine (3) is less than 0.5 MPa.

5. The aircraft engine test bench fuel system according to claim 4, characterized in that: The oil inlet pipeline (4) is provided with a second on-off valve (41) for controlling the on-off of the oil inlet pipeline (4) and a first oil filter (42) for filtering the fuel. The open oil tank (1) is provided with a first liquid level gauge (11). The first liquid level gauge (11) and the second on-off valve (41) are both connected to the control system. The first liquid level gauge (11) is used to feed back liquid level information in the open oil tank (1) to the control system. The control system controls the on-off of the second on-off valve (41) according to the liquid level information in the open oil tank (1).

6. The aircraft engine test bench fuel system according to claim 4, characterized in that: The boosting pipeline (5) is provided with a boosting pump (51) for boosting the fuel in the open fuel tank (1) to inject the fuel into the closed fuel tank (2) and a second one-way valve (52) for preventing the fuel from flowing back into the open fuel tank (1). The boosting pump (51) is connected to the control system. The closed fuel tank (2) is provided with a second liquid level gauge (21). The second liquid level gauge (21) is connected to the control system. The second liquid level gauge (21) is used to feed back liquid level information in the closed fuel tank (2) to the control system. The control system controls the start and stop of the boosting pump (51) according to the liquid level information in the closed fuel tank (2).

7. The aircraft engine test bench fuel system according to claim 4, characterized in that: The oil supply line (6) is provided with a third one-way valve (66) for preventing the fuel from flowing back to the closed oil tank (2); the oil return line (7) is provided with a fourth one-way valve (73) for preventing the fuel from flowing back to the outlet of the equivalent nozzle (71); and a third on-off valve (78) for controlling the on-off of the oil return line (7); the third on-off valve (78) is connected to the control system.

8. The aircraft engine test bench fuel system according to claim 7, characterized in that: The oil supply pipeline (6) and / or the oil return pipeline (7) are provided with a pressure gauge, a temperature gauge and a flow meter.

9. The aircraft engine test bench fuel system according to claim 8, characterized in that: A fourth on-off valve (63) and an emergency branch (64) for bypassing the flow meter are respectively arranged at both ends of the flow meter, and a fifth on-off valve (65) is arranged on the emergency branch (64).

10. The aircraft engine test bench fuel system according to claim 4, characterized in that: The open oil tank (1) is provided with a second oil-gas separator (12) for preventing fuel atomization from leaking into the atmosphere, and the closed oil tank (2) is provided with a safety valve and / or overflow valve for pressure relief.

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