A method for testing an interruption of lubricating oil in an aeroengine

Abstract

The application discloses an aero-engine lubricating oil interruption test method, sets monitoring parameters in the S1 step, records the monitoring parameters of the engine in the S2 step to the S4 step, obtains monitoring parameter alarm values through the monitoring parameters, interrupts the lubricating oil supply of the engine in the S7 step, and monitors whether the second current gas generator rotating speed, the second current output power, the second current power turbine inlet temperature and the second current ball bearing wall temperature exceed the corresponding first alarm values within the second preset time. Since the signs of bearing failure are directly judged through the monitoring parameters, the situation that the signs of bearing failure are judged by artificial through abnormal phenomena is avoided, the efficiency and accuracy of judging the signs of bearing failure are improved, the monitoring parameters of the engine are obtained through the S2 step to the S4 step, the monitoring parameter alarm values are obtained according to the monitoring parameters, the monitoring parameter alarm values correspond to the actual situation of the engine, and the inaccurate test results caused by the differences between different engines are avoided.

Description

Technical Field

[0001] This invention relates to the technical field of engine testing, and specifically to a method for testing oil interruption in aero-engines. Background Technology

[0002] During flight, aircraft engines may experience oil flow interruptions due to damage, maneuvering, repeated momentary overload flights, dogfighting damage, or improper maintenance. Oil interruption forces internal engine gears and bearings to operate in an unlubricated environment. The significant frictional heat generated by these components causes a rapid rise in temperature over time, leading to gear and bearing damage, such as gear seizure or bearing failure. These phenomena can completely disable the engine, resulting in serious consequences such as a crash. To prevent these consequences, engine development must determine the engine's operational capability range (time) without oil supply. Therefore, oil interruption tests are necessary. The principle of oil interruption is to cut off the oil supply to the oil pump inlet, allowing only air to enter the pump, thus simulating the oil interruption situation that occurs during aircraft flight by simulating the oil interruption condition.

[0003] Existing methods for testing the lubricating oil interruption of aero gas turbine engines employ a closed-loop control mode based on the rotational speed of the power turbine rotor or gas generator rotor. During the test, the engine casing vibration value, the high-frequency acquisition value of the compressor outlet pressure, and the test video are monitored to monitor the engine exhaust status, thereby enabling the monitoring of abnormal phenomena such as sudden changes in engine vibration value, compressor stall, and exhaust flame that occur when bearings fail.

[0004] However, the aforementioned lubricating oil interruption test method for aero gas turbine engines indirectly judges the signs of bearing failure by monitoring abnormal phenomena such as sudden changes in vibration values, compressor stall, and exhaust flame. It cannot accurately and efficiently determine the signs of bearing failure. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that the existing lubricating oil interruption test method indirectly judges the failure signs of the bearing by monitoring abnormal phenomena such as sudden changes in vibration value, compressor stall and exhaust flame, which cannot accurately and efficiently judge the failure signs of the bearing.

[0006] Therefore, this invention provides a method for testing oil interruption in an aero-engine. The engine includes a housing, a gas generator, a power turbine, a compressor, a combustion chamber, at least one ball bearing, and multiple roller bearings. The gas generator and the power turbine are both housed within the housing. The power turbine is located at the gas injection outlet of the combustion chamber, and the gas generated in the combustion chamber drives the power turbine to rotate. The compressor is housed within the housing and connected to the combustion chamber. The ball bearings are mounted on the upper rotor of the gas generator, and the roller bearings support the rotors within the aero-engine. The oil supply device includes an oil tank, a two-position three-way valve, and an oil pump. The oil tank is connected to the inlet of the oil pump via the two-position three-way valve, and the outlet of the oil pump is connected to each bearing component. The two-position three-way valve is also open to air. The test method includes:

[0007] S1: Set engine monitoring parameters, including gas generator speed, output power, power turbine inlet temperature, and ball bearing wall temperature;

[0008] S2: Set the control mode of the engine to closed-loop fuel supply control mode;

[0009] S3: Switch the two-position three-way valve to the first state that connects the lubricating oil pump to the lubricating oil tank, start the engine to ground idle state using the oil supply closed-loop control mode, and stay in the ground idle state for a first preset time.

[0010] S4: Slowly push the throttle lever up to keep the engine in the intermediate state for a first preset time, and record the current engine monitoring parameters, including the first current gas generator speed, the first current output power, the first current power turbine inlet temperature, and the first current ball bearing wall temperature. After recording the engine monitoring parameters, stop the engine.

[0011] S5: Set alarm values ​​for monitoring parameters based on the current engine monitoring parameters recorded in S4. The alarm values ​​for monitoring parameters include alarm values ​​for the speed of the first gas generator, alarm values ​​for the first output power, alarm values ​​for the inlet temperature of the first power turbine, and alarm values ​​for the wall temperature of the first ball bearing.

[0012] S6: The engine adopts the control method in S2 to switch the two-position three-way valve to the first state that connects the lubricating oil pump to the lubricating oil tank, start the engine to the ground idle state, and stay in the ground idle state for the first preset time;

[0013] S7: Slowly push the throttle lever up to bring the engine to the intermediate state, then switch the two-position three-way valve to the second state that connects the oil pump to the air, and immediately start timing, and monitor the front speed of the second current gas generator, the second current output power, the second current power turbine inlet temperature and the second current ball bearing wall temperature;

[0014] S8: When the timing in S7 reaches the second preset time, and the second current gas generator speed, second current output power, second current power turbine inlet temperature and second current ball bearing wall temperature do not exceed the corresponding first alarm value, switch the two-position three-way valve to the first state that connects the lubricating oil pump and the lubricating oil tank, and monitor the lubricating oil pressure.

[0015] S9: When the lubricating oil pressure exceeds the preset pressure value within the third preset time, pull down the throttle lever to make the engine work at 75% maximum continuous state for a fourth preset time, and monitor the third current speed, third current output power, third current power turbine inlet temperature and third current ball bearing wall temperature of the gas generator.

[0016] S10: When the third current speed, the third current output power, the third current power turbine inlet temperature, and the third current ball bearing wall temperature do not exceed the corresponding alarm values, and the fourth preset time is reached, pull down the throttle lever to bring the engine to ground idle state, stay there for the first preset time, and then stop the engine.

[0017] Optionally, in the above-mentioned aircraft engine lubricating oil interruption test method, the engine monitoring parameters in step S1 also include the rotational speed of the power turbine, the lubricating oil supply temperature, and the compressor outlet pressure.

[0018] Optionally, in the above-mentioned aircraft engine lubricating oil interruption test method, step S2 further includes setting the power turbine speed control, which adopts the vehicle-mounted hydraulic dynamometer control mode.

[0019] Optionally, the above-mentioned aircraft engine lubricating oil interruption test method, after step S3 and before step S4, further includes:

[0020] S31: Slowly push the throttle lever up, so that the engine stays in the idle state, 50% maximum continuous state, 75% maximum continuous state and maximum continuous state for a first preset time in sequence, in order to obtain reasonable values ​​of monitoring parameters.

[0021] Optionally, in the above-mentioned method for testing the interruption of lubricating oil in an aircraft engine, step S4 further includes: slowly pushing down the throttle lever to make the engine sequentially stay in the maximum state, 50% maximum continuous state, 75% maximum continuous state, in-flight idle state, and ground idle state for a first preset time, and then stopping the engine.

[0022] Optionally, the above-mentioned aircraft engine lubricating oil interruption test method, after step S6 and before step S7, further includes:

[0023] S61: Slowly push the throttle lever up, so that the engine stays in the idle state, 50% maximum continuous state, 75% maximum continuous state, maximum continuous state, intermediate state, and maximum state for a first preset time in sequence.

[0024] Optionally, the above-described aircraft engine lubricating oil interruption test method further includes, after step S8 and before step S9:

[0025] S81: If the lubricating oil pressure does not exceed the preset pressure value within the third preset time, stop the engine immediately and check the damage to the engine ball bearing.

[0026] Optionally, the above-mentioned aircraft engine lubricating oil interruption test method, step S4, further includes:

[0027] After recording the monitoring parameters of the intermediate state, the engine is kept in the 75% maximum continuous state for a first preset time, and the current engine monitoring parameters are recorded. The current engine parameters include the speed of the third current gas generator, the third current output power, the third current power turbine inlet temperature, and the third current ball bearing wall temperature. After recording the engine monitoring parameters, the engine is stopped.

[0028] The above S5 step also includes:

[0029] According to the alarm values ​​of the monitoring parameters set by the engine in the current 75% maximum continuous state detection parameter recorded by S4, including the alarm value of the second gas generator speed, the alarm value of the second output power, the alarm value of the second power turbine inlet temperature, and the alarm value of the second ball bearing wall temperature.

[0030] The process following step S8 and before step S9 includes:

[0031] S81: Slowly push the throttle lever up to bring the engine to the 75% maximum continuous state, then switch the two-position three-way valve to the second state that connects the oil pump to the air, and immediately start timing, and monitor the fourth current gas generator speed, fourth current output power, fourth current power turbine inlet temperature and fourth current ball bearing wall temperature of the gas generator;

[0032] When the timing in step S81 reaches the fifth preset time, and the fourth current speed, fourth current output power, fourth current power turbine inlet temperature, and fourth current ball bearing wall temperature do not exceed the corresponding second alarm value, the two-position three-way valve is switched to the first state that connects the lubricating oil pump to the lubricating oil tank, and the lubricating oil pressure is detected.

[0033] Optionally, in the above-mentioned aircraft engine lubricating oil interruption test method, when the second current gas generator speed, second current output power, second current power turbine inlet temperature and second current ball bearing wall temperature in step S7 exceed the corresponding first alarm value, and the timing time in step S7 does not exceed the second preset time, the two-position three-way valve is switched to the first state that connects the lubricating oil pump and the lubricating oil tank, and the lubricating oil pressure is monitored. If the lubricating oil pressure exceeds the preset pressure value in the third preset time, the engine is stopped immediately and the test is terminated.

[0034] When the fifth current speed, fifth current output power, fifth current power turbine inlet temperature, and fifth current ball bearing wall temperature in step S81 exceed the corresponding second alarm value, and the timing time in step S81 does not exceed the fourth preset time, the two-position three-way valve is switched to the first state that connects the lubricating oil pump and the lubricating oil tank, and the lubricating oil pressure is monitored. If the lubricating oil pressure exceeds the preset pressure value at the third preset time, the test is stopped immediately.

[0035] Optionally, the above-mentioned test method for oil interruption in aircraft engines,

[0036] When the time taken in step S7 exceeds the second preset time, and the second current speed of the gas generator, the second current output power, the second current power turbine inlet temperature, and the second current ball bearing wall temperature exceed the corresponding first alarm value, the engine shall be stopped immediately and the engine shall be inspected.

[0037] If the time taken in step S81 exceeds the fourth preset time, and the fifth current speed, fifth current output power, fifth current power turbine inlet temperature, and fifth current ball bearing wall temperature exceed the corresponding second alarm value, the engine shall be stopped immediately and the engine shall be inspected.

[0038] The technical solution provided by this invention has the following advantages:

[0039] 1. The method for testing the lubricating oil interruption of an aircraft engine provided by this invention sets monitoring parameters in step S1, including the rotational speed of the gas generator, output power, turbine inlet temperature, and ball bearing wall temperature. Steps S2 to S4 record the aforementioned monitoring parameters of the engine and obtain alarm values ​​for monitoring parameters. In step S7, the engine's lubricating oil supply is interrupted. Within a second preset time period, the rotational speed of the second current gas generator, the second current output power, the second current turbine inlet temperature, and the second current ball bearing wall temperature are monitored to see if they exceed the corresponding first alarm values. Since the bearing failure symptoms are directly determined through monitoring parameters, the manual judgment of bearing failure symptoms based on abnormal phenomena is avoided, and the efficiency of judging bearing failure symptoms is improved. By obtaining the engine's monitoring parameters through steps S2 to S4 and then obtaining alarm values ​​for monitoring parameters based on these parameters, the alarm values ​​correspond to the actual situation of the engine, avoiding inaccurate test results caused by slight differences between different engines.

[0040] 2. The method for testing the interruption of lubricating oil in an aircraft engine provided by this invention uses a closed-loop control mode for the engine's oil supply. This mode can automatically reduce the engine speed when the test fails, avoiding the risk of overheating and surge caused by automatic oil supply in conventional speed closed-loop control strategies, thus reducing the risk of the test.

[0041] 3. The method for testing the interruption of lubricating oil in an aircraft engine provided by the present invention requires the detection of lubricating oil pressure in step S8. This provides a preventive measure against the possibility of airlocks causing the failure of oil supply recovery during the interruption and restoration of oil supply by the lubricating oil pump, thereby avoiding greater damage to the engine caused by airlocks.

[0042] 4. The aero-engine lubricating oil interruption test method provided by this invention will immediately stop the engine when any current monitoring parameter exceeds the corresponding alarm value, thereby avoiding further damage to the bearing and reducing test losses. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the engine and lubricating oil supply device provided by the present invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] 11. Housing; 12. Gas generator; 13. Power turbine; 14. Compressor; 15. Ball bearing; 16. Roller bearing; 17. Ball bearing test point; 18. Test chamber air; 19. Combustion chamber;

[0047] 21. Oil tank; 22. Two-position three-way valve; 23. Oil pump; 24. First oil supply pipe; 25. Air supply pipe; 26. Second oil supply pipe; 27. Branch oil supply pipe. Detailed Implementation

[0048] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] The engine includes: a housing 11, a gas generator 12, a power turbine 13, a combustion chamber 19, at least two ball bearings 15, and multiple roller bearings 16. The gas generator 12 is a gas generator rotor, and the power turbine 13 is a power turbine unit. Both the gas generator 12 and the power turbine 13 are housed within the housing 11. One ball bearing 15 is fitted around the outer periphery of the gas generator 12 to support it, and the other ball bearing 15 is fitted around the outer periphery of the power turbine 13 to support it. The power turbine 13 is located at the gas outlet of the combustion chamber 19, which is housed within the housing 11. The gas generated in the combustion chamber 19 drives the power turbine 13 to rotate. The gas passing through the power turbine 13 continues to be ejected towards the tail of the gas generator 12, driving the gas generator 12 to rotate. A compressor 14 is also housed within the housing 11 and is connected to the combustion chamber 19. The compressor 14 is used to compress outside air into the combustion chamber 19. The roller bearings 16 support the rotors within the engine.

[0053] The lubricating oil supply device includes an oil tank 21, a two-position three-way valve 22, and an oil pump 23. The oil tank 21 is connected to the inlet of the oil pump 23 through the two-position three-way valve 22. The oil tank 21 is a lubricating oil storage device. The oil pump 23 provides high-pressure lubricating oil to the engine bearings and other friction pairs for lubrication and cooling, and pumps the lubricating oil accumulated in the bearing cavity back to the oil tank. The oil tank 21 and the oil pump 23 are connected to the engine through external pipelines. The outlet of the lubricating oil pump 23 is connected to each bearing component, and the two-position three-way valve 22 can be connected to the air. The lubricating oil tank 21 is connected to the two-position three-way valve 22 through the first oil supply pipe 24. The two-position three-way valve 22 is connected to the outside through the air supply pipe 25. That is, the two-position three-way valve 22 is connected to the air in the test room 18 through the air supply pipe 25, which is used to supply the air in the test room 18 to each bearing. The inlet of the lubricating oil pump 23 is connected to the two-position three-way valve 22 through the second oil supply pipe 26, and the outlet of the lubricating oil pump 23 is connected to each bearing through each branch oil supply pipe 27.

[0054] Example 1

[0055] This embodiment provides a method for testing oil interruption in an aircraft engine, including:

[0056] S1: Set the engine monitoring parameters, including gas generator speed, output power, turbine inlet temperature, ball bearing wall temperature, turbine speed, lubricating oil supply temperature, and compressor outlet pressure. The turbine speed, lubricating oil supply temperature, and compressor outlet pressure are crucial parameters for evaluating engine performance after the test. After the test, if the turbine speed, lubricating oil supply temperature, and compressor outlet pressure meet the predetermined values ​​(the values ​​measured before the test), the engine performance is considered good. Monitoring the turbine speed, lubricating oil supply temperature, and compressor outlet pressure is necessary whenever the engine is running.

[0057] S2: Set the engine control mode to fuel supply closed-loop control mode, and set the power turbine control mode to vehicle-mounted hydraulic dynamometer control mode. In fuel supply closed-loop control mode, the engine control system uses fuel supply as the control target, controlling the amount of fuel supplied to the engine based on the throttle lever angle on the vehicle-mounted dynamometer. In vehicle-mounted hydraulic dynamometer control mode, it is a speed closed-loop control mode, automatically controlling the power turbine speed to remain constant according to the given speed.

[0058] S3: Switch the two-position three-way valve to the first state that connects the lubricating oil pump and the lubricating oil tank. That is, the lubricating oil pump works to generate negative pressure. The lubricating oil in the lubricating oil tank flows sequentially through the first oil supply pipe, the two-position three-way valve, the second oil supply pipe, the lubricating oil pump and each branch oil supply pipe, and then is sent to each bearing. The engine starts using the closed-loop control mode of oil supply and slowly accelerates to the ground idle state, and stays for a first preset time. The first preset time is 3 minutes. As an alternative implementation method, those skilled in the art can adjust the first preset time as needed to simulate the state of aircraft takeoff.

[0059] S31: Slowly push the throttle lever up to simulate the aircraft's flight state, causing the engine to remain in idle, 50% maximum continuous state, 75% maximum continuous state, and maximum continuous state for a first preset time in sequence.

[0060] S4: Slowly push the throttle lever upwards, causing the engine to remain in the intermediate state for a first preset time, and record the current engine monitoring parameters, including the first current gas generator speed, the first current output power, the first current power turbine inlet temperature, and the first current ball bearing wall temperature. After recording the monitoring parameters, slowly push the throttle lever downwards, causing the engine to remain in the maximum state, 50% maximum continuous state, 25% maximum continuous state, air idle state, and ground idle state for the first preset time in sequence. Then, stop the engine. As an alternative implementation method, the engine can also be kept in the ground idle state to continue to the next step, namely step S5.

[0061] S5: Set alarm values ​​for monitoring parameters based on the current engine detection parameters recorded in S4. These alarm values ​​include the first gas generator speed alarm value, the first output power alarm value, the first power turbine inlet temperature alarm value, and the first ball bearing wall temperature alarm value. The first ball bearing wall temperature alarm value includes a first temperature alarm value and a first temperature change rate alarm value. Specific alarm values ​​for these monitoring parameters are shown in the table below.

[0062]

[0063] Wherein, TbW - current bearing outer ring temperature; TbW / dt - current bearing outer ring temperature change rate; ng - current gas generator speed; dng / dt - current speed change rate; Pdn - current output power; T45 - current power turbine inlet temperature alarm value; KI,N - first current ball bearing wall temperature; KI,N+30 - first temperature alarm value; 20 - first temperature change rate alarm value; 11 - first gas generator speed alarm value; KI,N - first current output power; KI,N*1.005 - first output power alarm value; KI,N - first current power turbine inlet temperature; KI,N+5 - first power turbine inlet temperature alarm value;

[0064] S6: When the engine starts from a stopped state, maintain and record the test conditions when monitoring parameters. The engine adopts the control mode in step S2, switches the two-position three-way valve to the first state where the lubricating oil pump and the lubricating oil tank are connected, starts the engine to the ground idle state, and stays in the ground idle state for a first preset time. As an alternative implementation method, if the engine does not stop in step S5, the next step, namely step S61, can be directly performed.

[0065] S61: Slowly push the throttle lever up, causing the engine to pause for a first preset time in the idle state, 50% maximum continuous state, 75% maximum continuous state, and maximum continuous state, respectively, to simulate the aircraft's flight state.

[0066] S7: Slowly push the throttle lever up to bring the engine to the intermediate state, then switch the two-position three-way valve to the second state, which connects the oil pump to the air. That is, the oil pump works to generate negative pressure. The air in the test chamber flows through the first air supply pipe, the two-position three-way valve, the second oil supply pipe, the oil pump, and the branch oil supply pipe in sequence, and is delivered to each bearing, so that the oil supply to the engine is interrupted. When the two-position three-way valve is switched, start timing immediately and detect the speed of the second current gas generator, the second current output power, the second current power turbine inlet temperature, and the second current ball bearing wall temperature.

[0067] When any of the monitored values ​​in step S7 exceeds the corresponding alarm value, and the timing in step S7 does not exceed the second preset time (30 seconds), those skilled in the art can adjust the second preset time as needed; switch the two-position three-way valve to the first state that connects the lubricating oil pump to the lubricating oil tank, and monitor the lubricating oil pressure. If the lubricating oil pressure does not exceed the preset pressure value within a third preset time (5 seconds), those skilled in the art can adjust the third preset time as needed; then immediately stop the machine and the test is terminated.

[0068] If the time taken in step S7 exceeds the second preset time, and any of the monitored values ​​in step S7 exceeds the corresponding alarm value, the engine shall be stopped immediately and the engine shall be inspected.

[0069] S8: When the timing in S7 reaches the second preset time, and the second current gas generator speed, second current output power, second current power turbine inlet temperature, and second current ball bearing wall temperature do not exceed the corresponding first alarm value, switch the two-position three-way valve to the first state that connects the lubricating oil pump to the lubricating oil tank, and monitor the lubricating oil pressure; the lubricating oil pressure needs to be detected in step S8 to provide preventive measures against the possibility of air lock during the process of interrupting and resuming the lubricating oil pump, which may lead to failure of oil supply recovery, and avoid greater damage to the engine caused by air lock.

[0070] S81: If the lubricating oil pressure does not exceed the preset pressure value within the third preset time, stop the engine immediately and check the damage to the engine bearing.

[0071] S9: When the lubricating oil pressure exceeds the preset pressure value within a third preset time, pull down the throttle lever to make the engine work at 75% maximum continuous state for a fourth preset time, which is 30 minutes. As an alternative implementation, those skilled in the art can adjust the fourth preset time as needed; and monitor the third current speed, third current output power, third current power turbine inlet temperature, and third current ball bearing wall temperature of the gas generator.

[0072] S10: When the third current speed, the third current output power, the third current power turbine inlet temperature, and the third current ball bearing wall temperature do not exceed the corresponding alarm values, pull down the throttle lever to bring the engine to ground idle state and stay there for a first preset time, and then stop the engine.

[0073] The above steps enable the aircraft engine lubrication interruption test. This interruption test method directly identifies bearing failure symptoms through monitoring parameters, avoiding the need for manual identification of bearing failure symptoms based on abnormal phenomena, and improving the efficiency of bearing failure symptom assessment. Steps S2 to S4 acquire engine monitoring parameters, and then alarm values ​​are obtained based on these parameters, ensuring that the alarm values ​​correspond to the actual engine conditions and avoiding inaccurate test results due to minor differences between different engines. The engine control mode is a closed-loop fuel supply control mode, which automatically reduces engine speed in case of test failure. This avoids the risks of overheating and surge caused by automatic fuel supply issues associated with conventional closed-loop speed control strategies, thus reducing the overall test risk.

[0074] Example 2

[0075] This embodiment provides a method for testing oil interruption in an aircraft engine, and also includes:

[0076] The above S4 step also includes:

[0077] After recording the monitoring parameters of the intermediate state, the engine is kept in the 75% maximum continuous state for a first preset time, and the current engine monitoring parameters are recorded. The current engine parameters include the speed of the fourth current gas generator, the fourth current output power, the fourth current power turbine inlet temperature, and the fourth current ball bearing wall temperature. After recording the engine monitoring parameters, the engine is stopped.

[0078] The above S5 step also includes:

[0079] Based on the current engine parameters recorded in S4 at 75% maximum continuous state, the monitoring parameter alarm values ​​include the second gas generator speed alarm value, the second output power alarm value, the second power turbine inlet temperature alarm value, and the second ball bearing wall temperature alarm value. The second ball bearing wall temperature alarm value includes a second temperature alarm value and a second temperature change rate alarm value. The specific monitoring parameter alarm values ​​are shown in the table below:

[0080]

[0081] The process following step S8 and before step S9 includes:

[0082] S81: Slowly push the throttle lever up to bring the engine to the 75% maximum continuous state, then switch the two-position three-way valve to the second state that connects the oil pump to the air, and immediately start timing, and monitor the fifth current gas generator speed, fifth current output power, fifth current power turbine inlet temperature and fifth current ball bearing wall temperature;

[0083] When the timing in step S81 reaches the fifth preset time, and the fifth current speed, fifth current output power, fifth current power turbine inlet temperature, and fifth current ball bearing wall temperature do not exceed the corresponding second alarm value, the two-position three-way valve is switched to the first state that connects the lubricating oil pump and the lubricating oil tank, and the lubricating oil pressure is detected; the fifth preset time is 3 seconds.

[0084] When any of the monitored values ​​in step S81 exceeds the corresponding alarm value, and the timing in step S81 has not exceeded the fourth preset time, the two-position three-way valve is switched to the first state that connects the lubricating oil pump and the lubricating oil tank, and the lubricating oil pressure is monitored. If the lubricating oil pressure exceeds the preset pressure value at the third preset time, the test is stopped immediately.

[0085] If the timed period in step S81 exceeds the fourth preset time, and any of the monitored values ​​in step S81 exceeds the corresponding alarm value, the engine shall be stopped immediately and the engine shall be inspected.

[0086] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for testing the interruption of lubricating oil in an aircraft engine, the engine comprising a housing (11), a gas generator (12), a power turbine (13), a compressor (14), a combustion chamber (19), at least one ball bearing (15), and multiple roller bearings (16), wherein the gas generator (12) and the power turbine (13) are both disposed within the housing (11), the power turbine (13) is disposed at the gas outlet of the combustion chamber (19), the gas generated by the combustion chamber (19) drives the power turbine (13) to rotate, and the compressor (14) The compressor (14) is located inside the housing (11), and the combustion chamber (19) is connected to the compressor (14). The ball bearing (15) is mounted on the gas generator (12), and the roller bearing (16) is used to support the rotors inside the engine. The lubricating oil supply device includes an oil tank (21), a two-position three-way valve (22), and an oil pump (23). The oil tank (21) is connected to the inlet of the oil pump (23) through the two-position three-way valve (22), and the outlet of the oil pump (23) is connected to each bearing component. The two-position three-way valve (22) is also connected to air. The characteristic of this device is that... The experimental method includes the following steps: S1: Set the engine monitoring parameters, including the gas generator speed, output power, power turbine inlet temperature, and ball bearing wall temperature; S2: Set the control mode of the engine to closed-loop fuel supply control mode; S3: Switch the two-position three-way valve (22) to the first state that connects the lubricating oil pump (23) to the lubricating oil tank (21), start the engine to ground idle state using the oil supply closed-loop control mode, and stay in the ground idle state for a first preset time; S4: Slowly push the throttle lever up to keep the engine in the intermediate state for a first preset time, and record the current engine monitoring parameters, including the first current gas generator speed, the first current output power, the first current power turbine inlet temperature, and the first current ball bearing wall temperature. After recording the engine monitoring parameters, stop the engine. S5: Set alarm values ​​for monitoring parameters based on the current engine monitoring parameters recorded in S4. The alarm values ​​for monitoring parameters include alarm values ​​for the speed of the first gas generator, alarm values ​​for the first output power, alarm values ​​for the inlet temperature of the first power turbine, and alarm values ​​for the wall temperature of the first ball bearing. S6: The engine adopts the control mode in S2, switches the two-position three-way valve (22) to the first state that connects the lubricating oil pump (23) with the lubricating oil tank (21), starts the engine to the ground idle state, and stays in the ground idle state for the first preset time; S7: Slowly push the throttle lever up to bring the engine to the intermediate state, then switch the two-position three-way valve (22) to the second state that connects the oil pump (23) to the air, and immediately start timing, and monitor the speed of the second current gas generator, the second current output power, the inlet temperature of the second current power turbine and the wall temperature of the second current ball bearing; S8: When the timing in S7 reaches the second preset time, and the second current speed of the gas generator, the second current output power, the second current power turbine inlet temperature and the second current ball bearing wall temperature do not exceed the corresponding first alarm value, switch the two-position three-way valve (22) to the first state that connects the lubricating oil pump (23) to the lubricating oil tank (21), and monitor the lubricating oil pressure; S9: When the lubricating oil pressure exceeds the preset pressure value within the third preset time, pull down the throttle lever to make the engine work at 75% maximum continuous state for a fourth preset time, and monitor the third current speed, third current output power, third current power turbine inlet temperature and third current ball bearing wall temperature of the gas generator. S10: When the third current speed, the third current output power, the third current power turbine inlet temperature, and the third current ball bearing wall temperature do not exceed the corresponding alarm values, and the fourth preset time is reached, pull down the throttle lever to bring the engine to ground idle state, stay there for the first preset time, and then stop the engine.

2. The method for testing oil interruption in an aircraft engine according to claim 1, characterized in that, In step S1 above, the engine monitoring parameters also include the speed of the power turbine, the lubricating oil supply temperature, and the compressor outlet pressure.

3. The method for testing oil interruption in an aircraft engine according to claim 2, characterized in that, The above S2 step also includes setting the speed control of the power turbine (13), which adopts the vehicle platform hydraulic dynamometer control mode.

4. The method for testing oil interruption in an aircraft engine according to claim 3, characterized in that, After step S3 and before step S4, the following is also included: S31: Slowly push the throttle lever up, so that the engine stays in the idle state, 50% maximum continuous state, 75% maximum continuous state and maximum continuous state for a first preset time in sequence, in order to obtain reasonable values ​​of monitoring parameters.

5. The method for testing oil interruption in an aircraft engine according to claim 4, characterized in that, Step S4 above also includes: slowly pushing down the throttle lever to make the engine stay in the maximum state, 50% maximum continuous state, 75% maximum continuous state, air idle state, and ground idle state for a first preset time in sequence, and then stopping the engine.

6. The method for testing oil interruption in an aircraft engine according to claim 4, characterized in that, After step S6 and before step S7, the following is also included: S61: Slowly push the throttle lever up, so that the engine stays in the idle state, 50% maximum continuous state, 75% maximum continuous state and maximum continuous state for a first preset time in sequence.

7. The method for testing oil interruption in an aircraft engine according to claim 4, characterized in that, The steps following S8 and preceding S9 include: S81: If the lubricating oil pressure does not exceed the preset pressure value within the third preset time, stop the engine immediately and check the damage to the ball bearings in the engine.

8. The method for testing oil interruption in an aircraft engine according to claim 7, characterized in that, The above S4 step also includes: After recording the monitoring parameters of the intermediate state, the engine is kept in the 75% maximum continuous state for a first preset time, and the current engine monitoring parameters are recorded. The current engine monitoring parameters include the speed of the fourth current gas generator, the fourth current output power, the fourth current power turbine inlet temperature, and the fourth current ball bearing wall temperature. After recording the engine monitoring parameters, the engine is stopped. The above S5 step also includes: According to the current engine recorded in S4, the alarm values ​​for monitoring parameters are set at 75% maximum continuous state detection parameters, including the second gas generator speed alarm value, the second output power alarm value, the second power turbine inlet temperature alarm value, and the second ball bearing wall temperature alarm value. The process following step S8 and before step S9 includes: S81: Slowly push the throttle lever up to bring the engine to the 75% maximum continuous state, then switch the two-position three-way valve (22) to the second state that connects the oil pump (23) to the air, and immediately start timing, and monitor the fifth current gas generator speed, fifth current output power, fifth current power turbine inlet temperature and fifth current ball bearing wall temperature of the gas generator (12); When the timing in step S81 reaches the fifth preset time, and the fifth current speed, fifth current output power, fifth current power turbine inlet temperature and fifth current ball bearing wall temperature do not exceed the corresponding second alarm value, the two-position three-way valve (22) is switched to the first state that connects the lubricating oil pump (23) to the lubricating oil tank (21), and the lubricating oil pressure is detected.

9. The method for testing oil interruption in an aircraft engine according to claim 8, characterized in that, When the second current gas generator speed, second current output power, second current power turbine inlet temperature and second current ball bearing wall temperature in step S7 exceed the corresponding first alarm value, and the timing time in step S7 does not exceed the second preset time, switch the two-position three-way valve (22) to the first state that connects the lubricating oil pump (23) to the lubricating oil tank (21), and monitor the lubricating oil pressure. If the lubricating oil pressure exceeds the preset pressure value in the third preset time, stop immediately and the test is terminated. When the monitored values ​​of the fifth current speed, fifth current output power, fifth current power turbine inlet temperature and fifth current ball bearing wall temperature in step S81 exceed the corresponding second alarm value, and the timing time in step S81 does not exceed the fourth preset time, the two-position three-way valve (22) is switched to the first state that connects the lubricating oil pump (23) and the lubricating oil tank (21), and the lubricating oil pressure is monitored. If the lubricating oil pressure does not exceed the preset pressure value in the third preset time, the test is stopped immediately.

10. The method for testing oil interruption in an aircraft engine according to claim 9, characterized in that... When the time taken in step S7 exceeds the second preset time, and the second current speed of the gas generator, the second current output power, the second current power turbine inlet temperature, and the second current ball bearing wall temperature exceed the corresponding first alarm value, the engine shall be stopped immediately and the engine shall be inspected. If the time taken in step S81 exceeds the fourth preset time, and the second current gas generator speed, second current output power, second current power turbine inlet temperature, and second current ball bearing wall temperature exceed the corresponding second alarm value, the engine shall be stopped immediately and the engine shall be inspected.

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