Method for preventing bearing from exceeding standard after test run of gas turbine

Abstract

The invention provides a method for preventing a bearing from exceeding the standard after test run of a gas turbine. The method comprises the following steps: selecting a process bearing, controlling the assembly process of the process bearing, controlling the environment of a test run rack, controlling the process of primary test run, performing fault detection on the process bearing after primary test run, assembling a new bearing in secondary test run, and leaving a factory of the new bearing in normal assembly in secondary test run. According to the fault detection condition after the aero-engine is subjected to one-time test run, the bearing is mainly subjected to abnormal damage standard exceeding; physical and chemical analysis is carried out on the bearing exceeding the standard, hard metal particles exist on the surface, and analysis considers that abnormal damage exceeding of the bearing surface is possibly related to uncleanness of a lubricating oil system; according to the principle, in the operation process of the bearing, hard particles enter all contact surfaces of the bearing and exceed the thickness of an oil film, and abnormal damage exceeds the standard. The method has the advantages that the problem that the gas turbine bearing exceeds the standard is solved, a direction is pointed out for solving the problem, a practical basis is provided, and the method has universal application value and wide market prospects.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine mechanical system design, and in particular to a method for preventing bearings from exceeding standards after a gas turbine test run. Background Art

[0002] The gas turbine is a modified gas turbine based on the aircraft engine. It is developed based on the experience of aircraft engine development and reference to advanced technologies in Europe and the United States. The working conditions (speed and load) of the gas turbine are relatively lower than those of aircraft engines. The mechanical system of the gas turbine mainly includes the main bearing, transmission system (central cone transmission device and accessory casing, etc.), lubrication system, etc. Taking the main bearing as an example, the main engine of the gas turbine is composed of the gas generator rotor and the power turbine rotor. The gas generator rotor uses two fulcrums 3 and 4, and the power turbine rotor uses three fulcrums 1, 2 and 5. The whole machine has five main bearings, see Figure 1 .

[0003] The gas turbine test run procedure includes the first test run and the second test run. The purposes of the first test run are mainly the following aspects: running-in the gas turbine; checking the manufacturing and assembly quality of the gas turbine and the vibration of the whole machine; checking the working reliability and matching of the gas turbine and its accessories, checking whether its parameters and characteristics meet the design requirements, and making preliminary adjustments; based on the results of the first test run of the gas turbine, determine whether it can be submitted for the second test run.

[0004] At present, during the first test run of the gas turbine, new bearings are installed to participate in a test run assessment, and then the bearing surface condition and related dimensions are disassembled and inspected. If they meet the technical documents, the bearings will participate in a second test run assessment and leave the factory normally. One of the main purposes of a test run is to check the manufacturing quality of related parts, and to allow particles from the running-in of the parts to enter the lubricating oil system. The amount of particles entering the lubricating oil system is random, which causes contamination of the lubricating oil system. Bearings are precision parts and have very high requirements for the working environment. The basic function of the lubrication system is to provide lubricating oil for lubrication and cooling to engine bearings and other components to reduce friction and wear on moving dual surfaces, prevent corrosion and surface hardening, and at the same time transfer heat and take away hard inclusions formed between the dual surfaces. This causes contaminated lubricating oil to enter the bearing, causing the bearing working surface to exceed the standard, see Figure 2 and Figure 3 .

[0005] Conventional troubleshooting method: After the bearing exceeds the standard in the first test run, replace the bearing with a new one and participate in the second test run assessment.

[0006] Since the gas turbine has been produced for many years, it is not realistic to make major improvements to the lubricating oil system. The conventional method of eliminating the problem is to replace the bearings with new ones. This urgently requires the study of a method to prevent the gas turbine bearings from exceeding the standard. Summary of the invention

[0007] The purpose of the present invention is to provide a method to prevent the bearings of fuel engines from exceeding the standard due to abnormal reasons after the first test of the aircraft engine, and this method has not been reported. The method is to use the bearings that exceed the standard due to abnormal reasons in the existing technical documents as fuel engine process bearings to participate in a test assessment; add a test run procedure before the first test and replace the lubricating oil; increase the frequency of oil change during the first test; and replace the bearings with new ones after the second test of the fuel engine and ship them out normally.

[0008] The present invention provides a method for preventing bearings from exceeding the standard after a gas turbine test run, which is characterized by comprising the following steps:

[0009] Process bearing selection:

[0010] Process bearings are bearings that exceed the existing technical documents due to surface damage and other reasons after a test run of an aircraft engine. This type of bearing has been verified and theoretically analyzed by ground testers and can meet at least one test run assessment of a relatively light engine, ensuring that the use of process bearings for installation will not affect the quality of the engine.

[0011] Process control of bearing assembly:

[0012] The technical requirements for the installation of process bearings are the same as those for new bearings. In the assembly process, cleaning of related parts is added to prevent excess particles from entering the engine, further improving the cleanliness of the engine during the assembly stage.

[0013] Test bench environment control:

[0014] Check the oil filter regularly and increase the frequency of oil filter replacement based on the inspection results; check the oil in the oil tank regularly and increase the frequency of oil replacement based on the inspection results, and replace the oil according to the inspection results during a test run; check the cleanliness of the oil system pipeline regularly and increase the cleaning frequency based on the inspection results; add a return oil filter to the oil return port; increase the cleanliness test of new oil to ensure that the new oil meets the cleanliness requirements; take relevant protection measures in dusty weather;

[0015] One test run process control:

[0016] Before a test run, conduct multiple test runs to drain the lubricating oil in the lubricating oil cavity, and increase the draining frequency based on the lubricating oil test results; during a test run, increase the frequency of lubricating oil testing to ensure that it meets the cleanliness requirements;

[0017] Fault inspection of process bearing after a test run:

[0018] After a test run, disassemble and inspect the surface quality of the process bearing; if it does not meet the requirements of the process bearing failure inspection, stop using the process bearing; if it meets the requirements of the process bearing failure inspection, the process bearing can continue to be used;

[0019] Second test run of new bearing assembly:

[0020] The second test run is completed and the new bearings are assembled normally before shipment.

[0021] Technical principle of the method of the present invention

[0022] Statistical analysis of the reasons for bearings exceeding the standard: According to the inspection results after a test run of an aircraft engine, it was found that the bearings mainly exceeded the standard due to abnormal damage (such as scratches). Physical and chemical analysis of the bearings that exceeded the standard showed the presence of hard metal particles on the surface. The analysis showed that the abnormal damage on the bearing surface exceeding the standard may be related to the uncleanness of the lubricating oil system. The principle is that during the operation of the bearing, hard particles enter the contact surfaces of the bearing, exceeding the oil film thickness, resulting in abnormal damage exceeding the standard.

[0023] Formulate bearing assembly control measures: formulate assembly control measures based on the reasons why the bearing exceeds the standard, and ensure that the cleanliness of the lubricating oil system in the assembly process meets the current standards.

[0024] Develop control measures for the test environment and test process: Develop control measures to address the problem of unclean lubricating oil system and ensure that particles dropped during the test will not cause damage to the bearings.

[0025] Process bearings participate in a test run assessment: During the first test run of the gas turbine, process bearings that meet the requirements of process bearing failure inspection are assembled, and normal new bearings are replaced during the second test run.

[0026] The technical principle of the present invention is to use bearings that have abnormal surface damage beyond the existing technical documents after a test run of an aircraft engine as engine process bearings to participate in a test run assessment, strengthen the control of lubricating oil cleanliness during the test run, and replace them with normal new bearings for shipment after a second test run.

[0027] Innovative analysis mode for over-standard bearings: using statistics to conduct physical and chemical analysis on over-standard bearings; using divergent thinking to analyze the mechanism of over-standard bearings; conducting in-depth analysis on the gas turbine assembly process, test environment, test process, etc., opening up new analytical ideas.

[0028] Study new troubleshooting methods:

[0029] Formulated the inspection requirements for process bearings for the first time;

[0030] For the first time, a process bearing was proposed to replace a new bearing in a test run;

[0031] For the first time, it was proposed to increase the frequency of cleaning the lubricating oil system to ensure the cleanliness of the lubricating oil system during the assembly and test runs.

[0032] The troubleshooting effect is good. After adopting the present invention, the bearing no longer exceeds the standard.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] The method for preventing bearings from exceeding the standard after the gas turbine test run described in the present invention solves the problem of bearings exceeding the standard in gas turbines, and points out the direction for solving such problems and provides a practical basis. It has universal application value and broad market prospects. Direct economic benefits: After adopting the present invention, bearings no longer exceed the standard. Social benefits: The control of lubricating oil cleanliness during the primary test run assembly process and the test run process improves the assembly quality and enhances the reliability of the gas turbine. It is applied to the selection of bearings for the primary test run of the gas turbine and adopts process bearings instead of new bearings to participate in the primary test run assessment and replaces new bearings for the second test run before leaving the factory. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0036] Figure 1 This is a schematic diagram of the main bearing position;

[0037] Figure 2 This is the typical morphology of outer ring surface damage;

[0038] Figure 3 This is a typical appearance of the outer ring exceeding the standard. DETAILED DESCRIPTION

[0039] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0040] Step 1: Comparative analysis of bearing conditions of gas turbines and aircraft engines

[0041] Although the gas turbine is improved from the aircraft engine, the operating conditions of the gas turbine are lower than those of the aircraft engine, especially the speed and load of the bearings are lower.

[0042] Step 2: Determine the number of engine bearing running-in times

[0043] Considering the characteristics of the gas turbine itself, it is clear that the bearings of the gas turbine only need one test run and assessment, which is different from the aircraft engine bearings which require two test runs and assessments (one test run and a second test run).

[0044] Step 3: Count the types of aircraft engine bearings that exceed the standard

[0045] Statistics on the types of bearings that exceed the standard after a test run of an aircraft engine show that the main type is abnormal surface damage. Analysis shows that this is mainly caused by unclean lubricating oil system and is not a bearing manufacturing problem. This lays the foundation for the subsequent selection of process bearings for gas turbines and the verification of the life of bearings that exceed the standard by testers.

[0046] Step 4: Test and verify the aircraft engine's excessive bearing life

[0047] From the existing aircraft engine bearings that exceeded the standard after the first test, the bearings with the most serious degree of exceeding the standard are selected for ground tester testing to verify whether the bearing life meets the first test time. Combined with the bearing's exceeding the standard morphology and verification results, the process bearing failure inspection requirements are compiled, and the bearings that meet the failure inspection requirements can be used as process bearings.

[0048] Step 5: Process bearing selection

[0049] Process bearings are bearings that have abnormal surface damage beyond the existing technical documents after a test run of an aircraft engine. This type of bearing is verified by a ground tester and can meet at least one test run assessment of a relatively light engine, ensuring that the use of process bearings will not affect the quality of the engine.

[0050] Step 6: Assembly process control

[0051] The technical requirements for the installation of process bearings are the same as those for new bearings. In the assembly process, cleaning of related parts is added to prevent excess particles from entering the gas turbine, further improving the cleanliness of the gas turbine during the assembly stage.

[0052] Step 7: Test environment control

[0053] Check the oil filter regularly, and increase the frequency of oil filter replacement based on the inspection results; check the oil in the oil tank regularly, and increase the frequency of oil replacement based on the inspection results, and replace the oil according to the inspection results during a test run; check the cleanliness of the oil system pipelines regularly, and increase the cleaning frequency based on the inspection results; add an oil return filter to the oil return port; increase the cleanliness test of new oil to ensure that the new oil meets the cleanliness requirements; take relevant protection measures in sandstorm weather.

[0054] Step 8: Commissioning process control

[0055] Before a test run, perform multiple test runs to drain the lubricating oil in the lubricating oil cavity, and increase the draining frequency based on the lubricating oil test results; during a test run, increase the frequency of lubricating oil testing to ensure that the cleanliness requirements are met.

[0056] Step 9: Process bearing disassembly inspection

[0057] After a test run, disassemble and inspect the surface quality of the process bearing. If it does not meet the requirements of the process bearing failure inspection, stop using the process bearing; if it meets the requirements of the process bearing failure inspection, the process bearing can continue to be used.

[0058] Step 10: After the second test run, remove the process bearing and assemble the new bearing before shipment.

[0059] Matters not covered by the present invention are known technologies.

[0060] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preventing bearings from exceeding the standard after a gas turbine test run, characterized in that: The steps include: Process bearing selection: Process bearings are bearings that exceed the existing technical documents due to surface damage and other reasons after a test run of an aircraft engine. This type of bearing has been verified and theoretically analyzed by ground testers and can meet at least one test run assessment of a relatively light engine, ensuring that the use of process bearings for installation will not affect the quality of the engine. Process control of bearing assembly: The technical requirements for the installation of process bearings are the same as those for new bearings. In the assembly process, cleaning of related parts is added to prevent excess particles from entering the engine, further improving the cleanliness of the engine during the assembly stage. Test bench environment control: Check the oil filter regularly and increase the frequency of oil filter replacement based on the inspection results; check the oil in the oil tank regularly and increase the frequency of oil replacement based on the inspection results, and replace the oil according to the inspection results during a test run; check the cleanliness of the oil system pipeline regularly and increase the cleaning frequency based on the inspection results; add a return oil filter to the oil return port; increase the cleanliness test of new oil to ensure that the new oil meets the cleanliness requirements; take relevant protection measures in dusty weather; One test run process control: Before a test run, conduct multiple test runs to drain the lubricating oil in the lubricating oil cavity, and increase the draining frequency based on the lubricating oil test results; during a test run, increase the frequency of lubricating oil testing to ensure that it meets the cleanliness requirements; Fault inspection of process bearing after a test run: After a test run, disassemble and inspect the surface quality of the process bearing; if it does not meet the requirements of the process bearing failure inspection, stop using the process bearing; if it meets the requirements of the process bearing failure inspection, the process bearing can continue to be used; Second test run of new bearing assembly: The second test run is completed and the new bearings are assembled normally before shipment.

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