A method for eliminating bearing over-standard after engine test run

Abstract

The application provides a method for eliminating bearing over-standard after gas turbine test run, which comprises the following steps: process bearing selection, process bearing assembly process control, test bench environment control, one-time test run process control, process bearing fault detection after one-time test run, new product bearing assembly for second-time test run, and normal assembly of new product bearing for second-time test run and delivery. According to the fault detection condition after one-time test run of an aero-engine, it is found that the bearing is mainly over-standard in abnormal damage; the over-standard bearing is subjected to physical and chemical analysis, and there are hard metal particles on the surface, and it is considered that the over-standard of the bearing surface abnormal damage is related to the uncleanliness of the oil system; the principle is that the hard particles enter the inside of each contact surface of the bearing during the operation of the bearing, exceed the oil film thickness, and cause over-standard of abnormal damage. The application has the advantages that the problem of over-standard of the gas turbine bearing is solved, the direction for solving the problem is indicated, the practical basis is provided, it has universal application value, and has wide market prospect.

Description

Technical Field

[0001] This invention relates to the field of gas turbine mechanical system design technology, and in particular to a method for preventing bearings from exceeding specifications after gas turbine commissioning. Background Technology

[0002] A gas turbine is a modified version of an aero-engine, developed based on aero-engine research and development experience and referencing advanced technologies from Europe and the United States. The operating conditions (speed and load) of a gas turbine are relatively lower than those of an aero-engine. The mechanical system of a gas turbine mainly consists of main bearings, a transmission system (central cone drive and accessory gearboxes, etc.), and a lubrication system. Taking the main bearings as an example, the main unit of a gas turbine consists of a gas generator rotor and a power turbine rotor. The gas generator rotor uses two support points (3 and 4), while the power turbine rotor uses three support points (1, 2, and 5). The entire turbine has five main bearings. (See...) Figure 1 .

[0003] The gas turbine commissioning procedure includes a primary commissioning and a secondary commissioning. The primary commissioning serves several purposes: to break in the gas turbine; to check the manufacturing and assembly quality of the gas turbine and the overall vibration; to check the operational reliability and compatibility of the gas turbine and its accessories, and to verify that its parameters and characteristics meet design requirements, making preliminary adjustments; and to determine whether the gas turbine can be submitted for a secondary commissioning based on the results of the primary commissioning.

[0004] Currently, during the initial commissioning phase of a gas turbine, new bearings are installed and tested. The bearings are then disassembled and inspected for surface condition and dimensions. If they meet the technical specifications, they undergo a second commissioning test and are then shipped normally. A primary purpose of the initial commissioning is to check the manufacturing quality of relevant components. It is permissible for particles from the break-in process to enter the lubrication system, and the amount of particles entering the lubrication system is random, leading to lubrication system contamination. Bearings are precision components with high requirements for their working environment. The basic function of the lubrication system is to provide lubricating and cooling oil to engine bearings and other components to reduce friction and wear on moving surfaces, prevent corrosion and surface hardening, and simultaneously dissipate heat and remove hard inclusions formed between the surfaces. This results in contaminated lubricating oil entering the bearing interior, causing the bearing's working surface to exceed safety standards. Figure 2 and Figure 3 .

[0005] Conventional troubleshooting method: If the bearing fails the test on the first run, replace it with a new bearing and conduct a second test.

[0006] Since gas turbines have been in production for many years, major improvements to the lubrication system are no longer feasible. The conventional troubleshooting method is to replace the bearings with new ones, which urgently requires the research of a method to prevent gas turbine bearings from exceeding the standards. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the existing technology by providing a method to prevent gas turbine bearings from exceeding specifications. No such troubleshooting method has been reported previously. This method involves using a bearing from an aero-engine that exceeds specifications due to anomalies during its first test run as a gas turbine process bearing for a subsequent test run; adding a trial operation procedure and changing the lubricating oil before the first test run; increasing the oil change frequency during the first test run; and replacing the bearing with a new one during the second gas turbine test run, ensuring normal delivery.

[0008] This invention provides a method for preventing bearing defects after gas turbine commissioning, characterized by the following steps:

[0009] Process bearing selection:

[0010] Process bearings are bearings that exceed the existing technical specifications after a single test run of an aero-engine due to surface damage or other reasons. These bearings, verified by ground testing equipment and theoretical analysis, can meet at least one single test run assessment of a gas turbine under relatively light operating conditions, ensuring that the use of process bearings in the engine will not affect the quality of the gas turbine.

[0011] Process control of bearing assembly:

[0012] The technical requirements for the installation of process bearings are the same as those for new bearings. During the assembly process, relevant parts are cleaned to prevent foreign particles from entering the gas turbine and further improve the cleanliness of the gas turbine during the assembly stage.

[0013] Test bench environmental control:

[0014] Regularly check the lubricating oil filter and increase the frequency of oil filter replacement based on the inspection results; regularly check the lubricating oil in the lubricating oil tank and increase the frequency of lubricating oil replacement based on the inspection results, and replace the lubricating oil according to the test results during each test run; regularly check the cleanliness of the lubricating oil system pipelines and increase the frequency of cleaning based on the inspection results; add a return oil filter at the lubricating oil return port; increase the testing of the cleanliness of new oil to ensure that the new oil meets the cleanliness requirements; take relevant protective measures during sandstorm weather;

[0015] Control of a single test run process:

[0016] Before each test run, perform multiple test runs to drain the lubricating oil from the lubricating oil chamber, and increase the frequency of draining based on the lubricating oil test results; during the test run, increase the frequency of lubricating oil testing to ensure that it meets the cleanliness requirements;

[0017] Process bearing fault inspection after one test run:

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

[0019] Second test run of the new bearing assembly:

[0020] The second test run was successful, and the new bearings were successfully assembled and shipped.

[0021] Technical Principles of the Method of the Invention

[0022] Statistical analysis of the causes of bearing defects exceeding standards: Based on the fault inspection results after a single test run of the aero-engine, it was found that the main cause of bearing defects exceeding standards was abnormal damage (such as scratches). Physicochemical analysis of the bearings exceeding standards revealed the presence of hard metal particles on their surfaces. The analysis suggests that the excessive abnormal damage on the bearing surface may be related to an unclean lubrication system. The principle is that during bearing operation, hard particles enter the interior of the bearing's contact surfaces, exceeding the oil film thickness, resulting in abnormal damage exceeding standards.

[0023] Develop bearing assembly control measures: Based on the reasons for the bearing exceeding the standard, develop assembly control measures to ensure that the cleanliness of the lubrication system during the assembly process meets the current standards.

[0024] Establish test environment and test process control measures: In response to the problem of unclean lubricating oil system, develop control measures to ensure that particles falling off during the test will not damage the bearing.

[0025] Process bearings undergo a trial run: During the first trial run of the gas turbine, process bearings that meet the requirements for troubleshooting are assembled, while normal new bearings are replaced during the second trial run.

[0026] The technical principle of this invention is to use bearings that exceed the scope of existing technical documents due to abnormal surface damage after the first test run of an aero-engine as process bearings for a gas turbine to participate in a test run. During the first test run, the lubricating oil cleanliness is strengthened, and the bearings are replaced with normal new bearings for shipment during the second test run.

[0027] An innovative analytical model for bearings exceeding standards was developed: statistical analysis was used to conduct physicochemical analysis of bearings exceeding standards; divergent thinking was used to analyze the mechanism of bearing exceeding standards; and in-depth analysis was conducted on the gas turbine assembly process, commissioning environment, and commissioning process, opening up new avenues for analysis.

[0028] Research new troubleshooting methods:

[0029] For the first time, requirements for process bearing failure inspection were formulated.

[0030] For the first time, it was proposed that process bearings replace new bearings in a trial run assessment.

[0031] This is the first time that the frequency of cleaning the lubricating oil system has been increased to ensure the cleanliness of the lubricating oil system during assembly and testing.

[0032] The troubleshooting effect is good; after adopting this invention, the bearings no longer exceed the standard.

[0033] Compared with the prior art, the advantages of this invention are:

[0034] The method for preventing bearing defects after gas turbine commissioning described in this invention solves the problem of bearing defects in gas turbines and provides practical guidance and practical evidence for solving such problems. It has widespread application value and broad market prospects. Direct economic benefits: After adopting this invention, bearing defects no longer occur. Social benefits: Controlling the lubricating oil cleanliness during the initial commissioning assembly process and the commissioning process improves assembly quality and enhances gas turbine reliability. It can be applied to the selection and installation of bearings during the initial commissioning of gas turbines, where process bearings are used instead of new bearings for the initial commissioning assessment, while new bearings are switched back for the second commissioning. Attached Figure Description

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0036] Figure 1 Schematic diagram of the main bearing location;

[0037] Figure 2 This describes the typical morphology of damage on the outer ring surface.

[0038] Figure 3 This is a typical morphology of the outer ring exceeding the standard. Detailed Implementation

[0039] The present invention will be further explained below with reference to specific implementation schemes, but it is not limited to the present invention. The structures, proportions, sizes, etc. shown in the accompanying drawings are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0040] Step 1: Comparative Analysis of Bearing Operating Conditions in Gas Turbines and Aero Engines

[0041] Although gas turbines are derived from aircraft engines, they operate under relatively lower conditions, particularly in terms of bearing speed and load.

[0042] Step 2: Determine the number of times the gas turbine bearings need to be run-in.

[0043] Based on the characteristics of the gas turbine itself, it is clear that the bearings of the gas turbine only need one test run, unlike the bearings of aero engines which require two test runs (one test run and two test runs).

[0044] Step 3: Statistically analyze the types of out-of-specification issues in aircraft engine bearings.

[0045] The statistical analysis of bearing defects after a single test run of an aero-engine revealed that the main issue was abnormal surface damage. This was found to be primarily caused by unclean lubrication systems, rather than bearing manufacturing defects. This provides a foundation for subsequent bearing selection in gas turbine processes and for verifying the lifespan of bearings that exceed specifications using testing equipment.

[0046] Step 4: Test and verify the excessive bearing life of aero-engines

[0047] From existing aero-engine bearings that exceeded specifications after a single test run, the bearing with the most severe exceedance was selected for ground testing to verify whether its lifespan met the requirements of a single test run. Based on the bearing's exceedance morphology and verification results, process bearing failure inspection requirements were developed. Bearings that meet these requirements can be considered process bearings.

[0048] Step 5: Selection of Process Bearings

[0049] Process bearings are those bearings whose surface damage exceeds the limits specified in existing technical documents after a single test run of an aero-engine. These bearings are verified through ground testing equipment to meet at least one single test run requirement for gas turbines operating under relatively light conditions, ensuring that the use of process bearings in the engine will not negatively impact the engine's quality.

[0050] Step Six: Assembly Process Control

[0051] The technical requirements for assembling process bearings are the same as those for new bearings. During assembly, additional cleaning of relevant components is performed to prevent foreign particles from entering the gas turbine, further improving the cleanliness of the gas turbine during the assembly phase.

[0052] Step 7: Test Run Environment Control

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

[0054] Step 8: Trial Run Process Control

[0055] Before each test run, perform multiple test runs to drain the lubricating oil from the lubricating oil chamber, and increase the frequency of draining based on the lubricating oil test results; during the test run, increase the frequency of lubricating oil testing to ensure that it meets the cleanliness requirements.

[0056] Step Nine: Disassembly and Inspection of Process Bearings

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

[0058] Step 10: Second test run - remove the process bearings and assemble new bearings for shipment.

[0059] Matters not covered in this invention are common knowledge.

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

Claims

1. A method for preventing bearing defects after gas turbine commissioning, characterized in that: Includes the following steps: Process bearing selection: Process bearings are bearings that fail to meet the requirements of existing post-test inspection documents after a single test run of an aero-engine due to surface damage. These bearings, verified by ground testing equipment and theoretical analysis, can meet at least one single test run assessment of a gas turbine under relatively light operating conditions, ensuring that the use of process bearings in the engine will not affect the quality of the gas turbine. Process control of bearing assembly: The technical requirements for the installation of process bearings are the same as those for new bearings. During the assembly process, relevant parts are cleaned to prevent foreign particles from entering the gas turbine and further improve the cleanliness of the gas turbine during the assembly stage. Test bench environmental control: Regularly check the lubricating oil filter and increase the frequency of oil filter replacement based on the inspection results; regularly check the lubricating oil in the lubricating oil tank and increase the frequency of lubricating oil replacement based on the inspection results, and replace the lubricating oil according to the test results during each test run; regularly check the cleanliness of the lubricating oil system pipelines and increase the frequency of cleaning based on the inspection results; add a return oil filter at the lubricating oil return port; increase the testing of the cleanliness of new oil to ensure that the new oil meets the cleanliness requirements; take relevant protective measures during sandstorm weather; Control of a single test run process: Before each test run, perform multiple test runs to drain the lubricating oil from the lubricating oil chamber, and increase the frequency of draining based on the lubricating oil test results; during the test run, increase the frequency of lubricating oil testing to ensure that it meets the cleanliness requirements; Process bearing fault inspection after one test run: After a test run, disassemble and inspect the surface quality of the process bearing; if it does not meet the process bearing failure inspection requirements, stop using the process bearing; if it meets the process bearing failure inspection requirements, the process bearing can continue to be used. Second test run of the new bearing assembly: The second test run was successful, and the new bearings were successfully assembled and shipped.

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