Rubber sealing ring accelerated aging test method for simulating aero-engine service environment

Abstract

The invention belongs to the technical field of aging life evaluation of rubber sealing elements, and relates to a rubber sealing ring accelerated aging test method for simulating the service environment of an engine. The method is composed of two test steps of accelerated aging of a simulated parking environment and accelerated aging of a simulated working condition environment, and a cycle test method of'high-temperature pressing + cooling pressure relief 'sub-cycle is nested in the step of accelerated aging of the simulated working condition environment. The method is used for aging law research and life prediction of the rubber sealing ring in simulating the service environment of an aero-engine, and comprehensively considers the environmental influence of the rubber sealing ring in two states of parking and working in the service process of the aero-engine. The aging process and mechanism of the rubber sealing ring in the service environment of the aero-engine can be well simulated through the test mode and the magnitude of related condition parameters, and the aging rule of the rubber sealing ring applied to the aero-engine can be more accurately obtained and serves as a basic test means for predicting the service life of the aero-engine.

Description

Technical field:

[0001] The invention belongs to the technical field of aging life evaluation of rubber seals, and relates to an accelerated aging test method for rubber seals simulating an engine service environment. Background technology:

[0002] Rubber seals are widely used in aircraft engines to seal lubricating oil, fuel, air and other media. Although the overall usage is not large, there are many types and application locations, and their role is very critical. If the rubber seals age and fail, oil leakage and air leakage will inevitably occur, which may lead to failure of components and functional failure, affecting the integrity of the whole equipment, or even damage to the whole equipment, or even stop the machine, resulting in safety accidents. At present, the aging and failure of rubber seals has become a key factor restricting the life of related products, directly affecting the reliability and safety of aircraft engines. Therefore, it is very necessary to carry out corresponding aging law research and life prediction for rubber seals used in aircraft engines.

[0003] At present, the aging law research on rubber seals mainly adopts two types of test methods: natural aging and accelerated aging. Among them: natural aging test is limited to studying the aging law of rubber seals under natural environmental conditions, and cannot be used to study the aging law of rubber seals when working on aircraft engines; accelerated aging test specifically includes: hot air aging, oxygen bomb aging, hot oil aging, artificial climate accelerated aging, wet heat aging, ozone aging, salt spray, mold and other test methods. On the one hand, some aging test methods (such as artificial climate accelerated aging) are quite different from the service environment of rubber seals on aircraft engines, and the aging law obtained from the study is not closely related to the aging law of rubber seals when serving on aircraft engines. On the other hand, these accelerated aging test methods still use a single factor of accelerated aging, which often cannot reflect the comprehensive aging effects of multiple factors such as natural environment temperature, working temperature, lubricating oil / fuel / air medium, medium pressure, mechanical deformation, etc. encountered by rubber seals when serving on aircraft engines. Summary of the invention:

[0004] In view of the above problems, considering that the service environment of an aircraft engine is divided into two states, parking and working, the rubber sealing ring in the parking state is mainly affected by factors such as high temperature and compression deformation in the natural atmospheric environment, and the rubber sealing ring in the working state is mainly affected by factors such as high temperature, medium, pressure and compression deformation in the working conditions of the aircraft engine, and comprehensively considering the environmental characteristics of the rubber sealing ring in which parking and working phases alternate during service and multiple environmental factors act in combination, the accelerated aging test method for rubber sealing rings simulating the engine service environment provided by the present invention can effectively simulate and reproduce the comprehensive aging environmental effects of the rubber sealing ring when it is in service on the aircraft engine, and improve the accuracy of the aging law research and life prediction of rubber sealing rings for aircraft engines.

[0005] In order to achieve the above object, the technical solution of the present invention is to provide a rubber seal ring accelerated aging test method simulating the service environment of an aircraft engine.

[0006] First, design a simulation test device with a pressure relief valve according to the assembly dimensions, component materials, surface treatment process, and medium pressure of the rubber sealing ring of the actual sealing structure; install the rubber sealing ring in the sealing ring groove of the simulation test device; inject the medium required to seal the actual sealing structure into the simulation test device so that the medium is under natural atmospheric pressure; place the simulation test device in a high-temperature test chamber to prepare for the test;

[0007] Then, an accelerated aging test was conducted using a cyclic test method consisting of two test steps: accelerated aging in a simulated parking environment and accelerated aging in a simulated working environment.

[0008] Step 1: Accelerated aging in simulated parking environment

[0009] Keep the medium pressure in the simulation test device at 0MPa, and adjust the high temperature test box so that the ambient temperature of the simulation test device rises and remains at the ambient temperature T p , and test under this ambient temperature and medium pressure conditions for 120h to 720h;

[0010] Step 2: Accelerated aging in simulated working environment

[0011] Accelerated aging in simulated operating environments is a cyclic test consisting of two sub-steps.

[0012] 1) High temperature pressing

[0013] Adjust the high temperature test chamber to simulate the ambient temperature of the test device T p Raise and maintain the accelerated aging temperature T w , use the medium pump to pressurize the medium in the simulation test device, so that the medium pressure value is maintained at the typical pressure value P when the aircraft engine is working. w, at the accelerated aging temperature Tw and medium pressure P w Test for 1h to 6h under the conditions.

[0014] 2) Cooling and pressure relief

[0015] Adjust the high temperature test chamber to change the ambient temperature of the simulated test device from the accelerated aging temperature T w The pressure in the simulated test device is reduced from P to room temperature through the pressure relief valve. w After the temperature drops to 0MPa and the pressure reduction step 2) is completed, the high temperature pressure step 1) is immediately repeated, and this cycle is repeated until the accelerated aging of the simulated working environment reaches the preset number of "high temperature pressure + temperature reduction and pressure relief" cycles N. w , or high temperature pressure P w Until it is unable to remain within the normal operating range of the medium system;

[0016] After the accelerated aging step 2 of the simulated working environment is completed, the accelerated aging step 1 of the simulated parking environment is immediately repeated, and this cycle is repeated until the entire accelerated aging test reaches the preset total number of cycles N, or the high temperature pressure P w The test ends when the medium system cannot be maintained within the normal operating range.

[0017] The accelerated aging of the simulated parking environment in step 1 is used to simulate the natural environment aging effect accumulated by the rubber sealing ring in the parking state during the one-year service of the aircraft engine.

[0018] In step 1, the accelerated aging temperature T p Higher than the natural ambient temperature and at least 20°C lower than the typical operating temperature of the medium.

[0019] The accelerated aging of the simulated working environment in step 2 is used to simulate the accumulated working environment aging effect of the rubber sealing ring in the working state during the one-year service of the aircraft engine.

[0020] In the step 1), the accelerated aging temperature T w Not lower than the typical working temperature of the medium and not higher than the maximum temperature that the rubber sealing ring material can withstand during operation.

[0021] In the step 1), the booster pump is matched with a specific medium type such as air, fuel, or lubricating oil.

[0022] The typical pressure value P of the aircraft engine when it is working in step 1) w It is a certain pressure value within the normal working range of a specific medium system such as an air system, a fuel system, or a lubricating oil system.

[0023] The number of cycles of "high temperature pressure + cooling and pressure relief" in step 2) is N wIt is set to 100 to 400 times, corresponding to the number of times an aircraft engine works each year.

[0024] The total number of cycles N of the accelerated aging test is set to 3 to 15 times, corresponding to the calendar year when the aircraft engine reaches the first overhaul period.

[0025] The assembly dimensions of the rubber sealing ring of the actual sealing structure include: the cross-sectional shape, depth, width and sealing gap of the sealing ring groove.

[0026] The accelerated aging test method for a rubber sealing ring simulating an engine service environment adopted by the present invention consists of two test steps, namely, accelerated aging in a simulated parking environment and accelerated aging in a simulated working environment. A cyclic test method of a "high temperature pressurization + cooling and pressure relief" sub-cycle is nested in the accelerated aging step in the simulated working environment. The method is used for studying the aging law and predicting the life of a rubber sealing ring simulating an aircraft engine service environment. The environmental influences of the rubber sealing ring in the parking and working states during the service history of the aircraft engine are comprehensively considered. The parking state is mainly affected by factors such as high temperature and compression deformation in the natural atmospheric environment. The working state is mainly affected by factors such as high temperature, medium, pressure and compression deformation in the working conditions of the aircraft engine. The test method and the values ​​of related condition parameters can better simulate the aging process and mechanism of the rubber sealing ring in the aircraft engine service environment, and can more accurately obtain the aging law of the rubber sealing ring applied to the aircraft engine, and serve as a basic test means for predicting its service life. Specific implementation method:

[0027] The following is a specific implementation method of the accelerated aging test method for a rubber seal ring simulating an engine service environment, and it is necessary to point out that this example is only applicable to further explanation of the present invention, but does not limit its scope. After reading this patent, professionals in this field will find that various improvements made without violating the essence of the present invention are obvious and belong to the scope of protection required by the present invention.

[0028] Accelerated aging test method for rubber seal rings simulating the service environment of aircraft engines.

[0029] First, design a simulation test device with a pressure relief valve according to the assembly dimensions, component materials, surface treatment process, and medium pressure of the rubber sealing ring of the actual sealing structure; install the rubber sealing ring in the sealing ring groove of the simulation test device; inject the medium required to seal the actual sealing structure into the simulation test device so that the medium is under natural atmospheric pressure; place the simulation test device in a high-temperature test chamber to prepare for the test;

[0030] Then, an accelerated aging test was conducted using a cyclic test method consisting of two test steps: accelerated aging in a simulated parking environment and accelerated aging in a simulated working environment.

[0031] Step 1: Accelerated aging in simulated parking environment

[0032] Keep the medium pressure in the simulation test device at 0MPa, and adjust the high temperature test box so that the ambient temperature of the simulation test device rises and remains at the ambient temperature T p , and test under this ambient temperature and medium pressure conditions for 120h to 720h;

[0033] Step 2: Accelerated aging in simulated working environment

[0034] Accelerated aging in simulated operating environments is a cyclic test consisting of two sub-steps.

[0035] 1) High temperature pressing

[0036] Adjust the high temperature test chamber to simulate the ambient temperature of the test device T p Raise and maintain the accelerated aging temperature T w , use the medium pump to pressurize the medium in the simulation test device, so that the medium pressure value is maintained at the typical pressure value (0.3MPa~6.5MPa) when the aircraft engine is working. w , at the accelerated aging temperature Tw and medium pressure P w Test for 1h to 6h under the conditions.

[0037] The accelerated aging in the simulated parking environment is used to simulate the natural environment aging effects accumulated by the rubber sealing ring in the parking state during the one-year service of the aircraft engine.

[0038] The accelerated aging temperature T p Higher than the natural environment temperature and lower than the typical working temperature of the medium (100℃~250℃) by at least 20℃.

[0039] The accelerated aging temperature T w Not lower than the typical working temperature of the medium (100℃~250℃), and not higher than the maximum temperature that the rubber sealing ring material can withstand during operation.

[0040] The boost pump is matched with specific medium types such as air, fuel, and lubricating oil.

[0041] The typical pressure value P of the aircraft engine when it is working w It is a certain pressure value within the normal working range of a specific medium system such as an air system, a fuel system, or a lubricating oil system.

[0042] 2) Cooling and pressure relief

[0043] Adjust the high temperature test chamber to change the ambient temperature of the simulated test device from the accelerated aging temperature T wThe pressure in the simulated test device is reduced from P to room temperature through the pressure relief valve. w After the temperature drops to 0MPa and the pressure reduction step 2) is completed, the high temperature pressure step 1) is immediately repeated, and this cycle is repeated until the accelerated aging of the simulated working environment reaches the preset number of "high temperature pressure + temperature reduction and pressure relief" cycles N. w , or high temperature pressure P w Until it can no longer be maintained within the normal working range of the medium system; the accelerated aging of the simulated working environment is used to simulate the accumulated working environment aging effect of the rubber sealing ring in the working state during the service of an aircraft engine for one year.

[0044] The number of cycles Nw of "high temperature pressure relief + cooling and pressure relief" is set to 100 to 400 times, corresponding to the number of times the aircraft engine works each year.

[0045] After the accelerated aging step 2 of the simulated working environment is completed, the accelerated aging step 1 of the simulated parking environment is immediately repeated, and this cycle is repeated until the entire accelerated aging test reaches the preset total number of cycles N, or the high temperature pressure P w The test ends when the medium system cannot be maintained within the normal operating range.

[0046] The total number of cycles N of the accelerated aging test is set to 3 to 15 times, corresponding to the calendar year when the aircraft engine reaches the first overhaul period. The assembly dimensions of the rubber sealing ring of the actual sealing structure include: the cross-sectional shape, depth, width and sealing gap of the sealing ring groove.

[0047] Example:

[0048] The FX-17 fluororubber seal ring used in the fuel system pipeline of an aircraft engine has an inner diameter of Φ142.5mm and a cross-sectional diameter of Φ21.8mm. It is installed in a a On a 46.34mm TC4 titanium alloy (without surface treatment) pipeline, the bottom diameter of the seal ring shaft groove is Φ g 43.5mm, the shaft groove width is 2.6mm, the outer cylinder for sealing is also made of TC4 titanium alloy (without surface treatment), and the matching hole diameter is Φ A 46.34mm, the sealing medium is Pegasus II lubricating oil, the typical working temperature is 200℃, and the normal working range of Pegasus II lubricating oil pressure in the fuel system pipeline of the aircraft engine is 0.3MPa~0.5MPa.

[0049] First, design and process a simulation test device for accelerated aging test, install FX-17 fluororubber sealing ring, and fill the simulation test device with Pegasus II lubricating oil. Preferably, the main body of the simulation test device is made of TC4 titanium alloy used in actual components. The main body of the device consists of two parts: a cylinder and a cylinder cover: the inner diameter of the cylinder is 150mm, the outer diameter is 158mm, the height is 50mm, the wall thickness is 4mm, one end is closed and the other end is open, and a needle pressure relief valve is set at the closed end; the cylinder cover has a diameter of 158mm and a thickness of 6mm. Three pipe openings with an outer diameter of 46.34mm, an inner diameter of 35mm, and a length of 10mm are opened and welded on the cylinder cover, and a bottom diameter of Φ is processed on the three pipe openings respectively. g The axial groove is 43.5mm and 2.6mm wide, and the cylinder cover is sealed and welded to the open end of the cylinder. FX-17 fluororubber sealing rings with an inner diameter of Φ142.5mm and a cross-sectional diameter of Φ21.8mm are installed on the axial grooves of the three pipe openings respectively; one of the pipe openings is blocked with a closed round cap (plug, made of TC4 titanium alloy) with an outer diameter of 66mm and an inner diameter of 46.34, and the closed round cap is fixed to the cylinder cover through a flange connection; the other two pipe openings and the inlet / outlet oil pipes and their valves are connected with a through-hole round cap (made of TC4 titanium alloy) with an outer diameter of 66mm and an inner diameter of 46.34, and the two through-hole round caps are also fixed to the cylinder cover through a flange connection. With one end of the cylinder cover of the simulation test device facing upward, use the external oil pump, oil inlet pipe, and oil outlet pipe to inject Pegasus II lubricating oil into the simulation test device. When Pegasus II lubricating oil is full, close the valves of the oil inlet pipe and the oil outlet pipe to seal the Pegasus II lubricating oil in the simulation test device. Turn the simulation test device upside down so that the closed end of the cylinder and the needle pressure relief valve face vertically upward, manually open the needle pressure relief valve so that the pressure of Pegasus II lubricating oil is at natural atmospheric pressure (i.e. not sealed, the pressure gauge on the lubricating oil pipeline shows 0MPa), and place the simulation test device in the STPH-102 high temperature test box to prepare for the test.

[0050] Then, the accelerated aging test was carried out using a cyclic test method consisting of two test steps: accelerated aging in a simulated parking environment and accelerated aging in a simulated working environment.

[0051] Step 1): Accelerated aging in simulated parking environment

[0052] The Pegasus II lubricating oil pressure in the simulation test device was maintained at 0 MPa, and the STPH-102 high-temperature test chamber was adjusted so that the ambient temperature of the simulation test device was increased and maintained at an accelerated aging temperature of 150°C (much higher than the highest temperature of various natural environments and 50°C lower than the typical operating temperature), and the test was conducted at 0 MPa and 150°C for 360 hours.

[0053] Step 2): Accelerated aging in simulated working environment

[0054] Accelerated aging in simulated operating environments is a cyclic test consisting of two sub-steps.

[0055] Sub-step 1): High temperature pressing

[0056] Close the manually opened needle pressure relief valve to keep it in the automatic opening state. Adjust the STPH-102 high temperature test chamber, raise the ambient temperature of the simulation test device from 150℃ and maintain it at the accelerated aging temperature of 220℃ (not lower than the typical working temperature of Pegasus II lubricant 200℃, and not higher than the maximum temperature of FX-17 fluororubber sealing ring material that can withstand 250℃ when working (specified in the material manual)), use an external oil pump to pressurize the Pegasus II lubricant in the simulation test device, keep its pressure value at the typical pressure value of 0.5MPa when the aircraft engine is working, and test for 4h at 0.5MPa and 220℃.

[0057] Sub-step 2): Cooling and depressurization

[0058] The STPH-102 high temperature test chamber is regulated to reduce the ambient temperature of the simulation test device from 220°C to room temperature, and the pressure relief valve is manually opened to reduce the pressure of the Pegasus II lubricating oil in the simulation test device to 0MPa. After the cooling and pressure relief (sub-step 2) process is completed, the high temperature pressure relief (sub-step 1) process is immediately repeated, and this cycle is repeated until the accelerated aging (step 2) of the simulated working environment reaches the pre-set "high temperature pressure relief + cooling and pressure relief" cycle of 250 times (corresponding to 250 times of aircraft engine operation per year), or the pressure value of the Pegasus II lubricating oil during high temperature pressure relief is lower than the lower limit of its normal working range of 0.3MPa.

[0059] After the accelerated aging in the simulated working environment (step 2) is completed, the accelerated aging process in the simulated parking environment (step 1) is immediately repeated, and this cycle is repeated until the entire accelerated aging test reaches a preset total number of cycles of 10 times (corresponding to 10 calendar years when the first overhaul period of the aircraft engine is 10,000 hours and the number of working hours per year is 1000 hours), or the pressure value of the Pegasus II lubricating oil during high temperature pressurization is lower than the lower limit of its normal working range of 0.3MPa, and the test is completed.

Claims

1. The accelerated aging test method for rubber sealing rings simulating the service environment of aircraft engines is characterized by: Design a simulation test device with a pressure relief valve according to the rubber seal ring assembly size, component materials, surface treatment process, and medium pressure of the actual sealing structure; Install the rubber sealing ring in the sealing ring groove of the simulation test device; Inject the sealing medium required for the actual sealing structure into the simulation test device so that the medium is under natural atmospheric pressure; place the simulation test device in a high-temperature test chamber to prepare for the test; Then, an accelerated aging test was conducted using a cyclic test method consisting of two test steps: accelerated aging in a simulated parking environment and accelerated aging in a simulated working environment. Step 1: Accelerated aging in simulated parking environment Keep the medium pressure in the simulation test device at 0MPa, and adjust the high temperature test box so that the ambient temperature of the simulation test device rises and remains at the ambient temperature T p , and test under this ambient temperature and medium pressure conditions for 120h to 720h; Step 2: Accelerated aging in simulated working environment Accelerated aging in simulated operating environments is a cyclic test consisting of two sub-steps. 1) High temperature pressing Adjust the high temperature test chamber to simulate the ambient temperature of the test device T p Raise and maintain the accelerated aging temperature T w , use the medium pump to pressurize the medium in the simulation test device, so that the medium pressure value is maintained at the typical pressure value P when the aircraft engine is working. w , at the accelerated aging temperature Tw and medium pressure P w Test for 1h to 6h under the conditions. 2) Cooling and pressure relief Adjust the high temperature test chamber to change the ambient temperature of the simulated test device from the accelerated aging temperature T w The pressure in the simulated test device is reduced from P to room temperature through the pressure relief valve. w After the temperature drops to 0MPa and the temperature reduction and pressure relief step 2) is completed, the high temperature pressure relief step 1) is immediately repeated, and this cycle is repeated until the accelerated aging of the simulated working environment reaches the preset number of "high temperature pressure relief + temperature reduction and pressure relief" cycles N. w , or high temperature pressure P w Until it is unable to remain within the normal operating range of the medium system; After the accelerated aging step 2 of the simulated working environment is completed, the accelerated aging step 1 of the simulated parking environment is immediately repeated, and this cycle is repeated until the entire accelerated aging test reaches the preset total number of cycles N, or the high temperature pressure P w The test ends when the medium system cannot be maintained within the normal operating range.

2. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The accelerated aging of the simulated parking environment in step 1 is used to simulate the natural environment aging effect accumulated by the rubber sealing ring in the parking state during the one-year service of the aircraft engine.

3. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: In step 1, the accelerated aging temperature T p Higher than the natural ambient temperature and at least 20°C lower than the typical operating temperature of the medium.

4. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The accelerated aging of the simulated working environment in step 2 is used to simulate the accumulated working environment aging effect of the rubber sealing ring in the working state during the one-year service of the aircraft engine.

5. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: In the step 1), the accelerated aging temperature T w Not lower than the typical working temperature of the medium and not higher than the maximum temperature that the rubber sealing ring material can withstand during operation.

6. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: In the step 1), the booster pump is matched with a specific medium type such as air, fuel, or lubricating oil.

7. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The typical pressure value P of the aircraft engine when it is working in step 1) w It is a certain pressure value within the normal working range of a specific medium system such as an air system, a fuel system, or a lubricating oil system.

8. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The number of cycles of "high temperature pressure + cooling and pressure relief" in step 2) is N w It is set to 100 to 400 times, corresponding to the number of times an aircraft engine works each year.

9. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The total number of cycles N of the accelerated aging test is set to 3 to 15 times, corresponding to the calendar year when the aircraft engine reaches the first overhaul period.

10. The accelerated aging test method for rubber sealing rings simulating the service environment of an aircraft engine according to claim 1, characterized in that: The assembly dimensions of the rubber sealing ring of the sealing structure include: the cross-sectional shape, depth, width and sealing gap of the sealing ring groove.