Airworthiness Compliance Determination Method for Aviation Turbine Engine Lubricants

Abstract

The present invention relates to the technical field of turbine oil testing, specifically a method for determining the airworthiness compliance of aviation turbine engine lubricating oil, comprising: conducting a certification of the turbine oil according to standards; if the certification is passed, a CTSOA is obtained; if the certification is not passed, the turbine oil is determined to be unairworthy; conducting a test of the turbine oil on an engine test bench for no less than a preset number of C cycles; if the test is passed, a STC is obtained; if the test is not passed, the turbine oil is determined to be unairworthy; applying the turbine oil on a designated route for no less than a preset flight time, and monitoring the application; if the monitored application passes, the turbine oil is determined to be airworthy; if the monitored application fails, the turbine oil is determined to be unairworthy. This solution can determine the airworthiness certification of the turbine oil and ensure the accuracy and completeness of the determination.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine lubricating oil detection, in particular to a method for determining the airworthiness compliance of aviation turbine engine lubricating oil. Background Art

[0002] Aviation turbine engine lubricating oil (hereinafter referred to as turbine lubricating oil) is the "blood" of the engine, which plays the role of lubricating, cooling, sealing and cleaning the engine.

[0003] With the rapid development of my country's economy, the country's civil aviation industry has grown rapidly, becoming the world's second-largest civil aviation transport nation after the United States. Demand for aviation lubricants has also increased significantly. However, due to Western technological blockades, domestically produced turbine lubricants lack access to key airworthiness verification test data, such as gear load capacity, bearing deposition performance, and gas-phase coking. This prevents domestically produced turbine lubricants from obtaining certification and approval from international airworthiness authorities. Furthermore, my country has yet to establish a comprehensive and accurate conformity assessment methodology for turbine lubricant airworthiness certification. This has limited the development and production of domestically produced turbine lubricants, severely hindering their localization. Therefore, my country's civil aviation industry urgently needs a comprehensive and accurate conformity assessment methodology for turbine lubricant airworthiness certification. Summary of the Invention

[0004] The present invention aims to provide a method for determining the airworthiness compliance of aviation turbine engine lubricating oil, which can determine the compliance of turbine lubricating oil with relevant airworthiness requirements and ensure the accuracy and completeness of the judgment.

[0005] The present invention provides the following basic solution: a method for determining the airworthiness compliance of a turbine lubricating oil used as a lubricating oil for an aviation turbine engine, comprising the following contents:

[0006] CTSOA certification: The turbine lubricant is certified according to the standards. If it passes the certification, it will obtain CTSOA and undergo engine STC certification. If it fails the certification, the turbine lubricant is deemed unairworthy.

[0007] Engine STC certification: Turbine lubricating oil is tested on an engine test bench for no less than a preset number of C cycles. If the test passes, the oil is awarded STC and can be used on routes. If the test fails, the oil is deemed unairworthy.

[0008] Route application: Apply the turbine oil to the designated route for a period of not less than the preset flight time, and monitor the application. If the monitoring application passes, the turbine oil is deemed airworthy; if the monitoring application fails, the turbine oil is deemed unairworthy.

[0009] Description: CTSOA: Technical Standards Regulations Project Approval;

[0010] STC: Supplemental Type Qualified.

[0011] Beneficial Effects of the Basic Plan: This plan begins with turbine oil testing and progresses through CTSOA certification, engine STC certification, and line application certification, ultimately concluding with the actual application level. This plan encompasses the entire spectrum of turbine oil compliance with airworthiness regulations and standards, including laboratory testing, full-scale ground engine bench testing, and line application monitoring testing. This ensures compliance of various turbine oil performance parameters with airworthiness regulations and technical standards. Each airworthiness certification step must be passed before proceeding to the next step. CTSOA certification involves certifying the turbine oil according to technical standards, while engine STC certification involves testing for no fewer than a preset number of cycles. Line application monitoring involves testing for no less than a preset flight duration, ensuring the effectiveness and accuracy of airworthiness certification decisions.

[0012] In summary, carrying out the airworthiness certification and verification of turbine lubricants in accordance with the requirements of this plan can determine the compliance of turbine lubricants with airworthiness regulations and technical standards, and ensure the accuracy and completeness of the judgment.

[0013] Furthermore, the CTSOA certification includes: reviewing the chemical composition and performance of the turbine lubricant according to the requirements of the CTSO-2C704 standard; if the certification is passed, the CTSOA is obtained and the engine STC certification is carried out; if the certification is not passed, the turbine lubricant is determined to be unairworthy;

[0014] The chemical composition review includes: determining whether the components in the turbine lubricating oil meet the preset chemical composition requirements;

[0015] Performance review, including type inspection and quality control inspection.

[0016] Beneficial effects: Chemical composition requirements and performance requirements certification, certifying the chemical composition and product performance of turbine lubricating oil to meet airworthiness standards.

[0017] Furthermore, the type inspection includes: conducting physical property tests, chemical property tests, stability performance tests, deposition performance tests, friction performance tests and additional tests on the turbine lubricating oil, and judging whether the turbine lubricating oil meets the type inspection requirements based on the test results. If so, a quality control inspection is conducted; if not, the turbine lubricating oil is judged to be unairworthy.

[0018] The quality control inspection includes: when batches of turbine lubricants that have passed type inspection are produced, quality control inspection is carried out on no less than preset batches of turbine lubricants to determine whether the turbine lubricants meet the quality control inspection requirements. If so, the turbine lubricants are certified to obtain CTSOA and undergo engine STC certification; if not, the turbine lubricants are determined to be unairworthy. The quality control inspection includes tests for kinematic viscosity, pour point, open-cell flash point, foam characteristics, total acid number, sediment / ash content, trace metal content, oxidation corrosion stability, thermal stability corrosion, dynamic coking, and gas phase coking.

[0019] Beneficial Effects: Type testing comprehensively evaluates the various properties of turbine lubricants, ensuring the integrity of performance testing and serving as the primary means of confirming compliance with airworthiness regulations and standards. Quality control testing is a factory release test for batches of turbine lubricants that have passed type testing. It determines whether the performance of each batch, as well as the performance differences between batches, meets technical standards. This ensures batch stability and ensures that the performance of subsequent large-scale production turbine lubricants is consistent with that of the type testing.

[0020] Furthermore, the engine STC certification includes:

[0021] Drain and clean the engine stand for maintenance;

[0022] Replace the turbine oil on the engine test bench;

[0023] Conduct engine C cycle test; the number of cycles shall not be less than the preset C cycle number;

[0024] During the engine C cycle test, engine operation data collection and analysis, turbine oil consumption monitoring and sampling analysis are performed;

[0025] After the engine C cycle test, perform oil sampling analysis, visual inspection and disassembly inspection;

[0026] Based on the engine operation data collection and analysis results, sampling analysis results, visual inspection results and disassembly inspection results, determine whether each result meets the preset engine STC certification requirements. If so, obtain the STC and implement route application; if not, determine that the turbine lubricant oil is not airworthy.

[0027] Beneficial effect: During the engine STC certification, the engine test bench is drained and cleaned to prevent the original turbine lubricating oil from affecting the test results.

[0028] Furthermore, the preset engine STC certification requirements include:

[0029] The change trends of various parameters of the engine equipped with the test turbo lubricant over the cycle number are consistent with those of the reference turbo lubricant, with no obvious mutations; the reference turbo lubricant is a commercial turbo lubricant;

[0030] During the engine C cycle test, the test engine did not exhibit any adverse operating conditions such as parameter exceeding limits, surge, slow acceleration, and / or speed hanging caused by the turbine lubricant. During the engine STC certification, no adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were found, and no engine component debris exceeding preset limits was found in the oil filter or magnetic plug.

[0031] After the engine C cycle test, the visual inspection results of the test engine's TGB, AGB, IGB and lubricating oil system were normal, and there was no oil leakage related to the replacement of turbine lubricating oil in the test engine and related components of the lubricating oil system.

[0032] Beneficial Effects: The pre-set engine STC certification requirements for the turbine oil used as the test lubricant include engine operating parameter comparison, test oil performance trend monitoring, and disassembly inspection and evaluation of key engine components, ensuring comprehensiveness and accuracy of test judgments. Furthermore, mainstream commercial turbine oils were selected as reference oils. By comparing and analyzing the performance differences between the test oil and the reference oil, the test oil's compliance with engine design requirements was determined, further improving the accuracy of airworthiness verification.

[0033] Furthermore, the preset C cycle number is at least 2000 times.

[0034] Beneficial Effect: The default C-cycle count of at least 2,000 prevents a low test cycle count from failing to fully verify the potential impact of the test turbine oil on the engine under different operating conditions. For example, oil corrosion on non-metallic seals in the engine oil system typically occurs after 1,500 cycles. Fewer test cycles increase the risk of problems with the test oil during subsequent flight operations.

[0035] Furthermore, the route application includes: applying the turbine lubricating oil to a designated aircraft model and a designated route, and conducting a route application comparison test;

[0036] A single test includes: replacing the test turbine oil and reference turbine oil in the engines on both sides of the test aircraft respectively, and conducting two flight segments of testing, and the flight time of the two segments is not less than the first preset flight time and the second preset flight time respectively. The two segments are a short-range route with short takeoffs and landings and a long-range route with long takeoffs and landings;

[0037] Collect and record the operating data of the aircraft and engine in each flight segment during the test flight;

[0038] Sampling and analysis of turbine oil in engines, starters and IDGs on both sides;

[0039] Conduct visual and disassembly inspections of the engine oil filter and metal chip sensor;

[0040] Based on the comparative analysis of the flight test data collected and recorded for each flight segment, visual inspection results, test oil sampling and analysis, and disassembly inspection results, determine whether the test is qualified. If so, proceed to the next test; if not, determine that the turbine oil is not airworthy.

[0041] After the visual inspection and sampling analysis are completed, the test engine will be replaced with the original commercial turbine oil as needed, and the engine oil system, starter and IDG will be cleaned and maintained to restore the engine to an airworthy state;

[0042] The number of tests is determined based on the total flight time of the test being no less than the preset flight time, and it is judged whether each test meets the preset route application qualification requirements. If so, the turbine lubricant is determined to be airworthy; if not, the turbine lubricant is determined to be unairworthy.

[0043] Beneficial effects: A single test includes testing two flight segments, the flight time of the two segments is not less than the first preset flight time and the second preset flight time respectively, and the two segments should be a short-distance route with short takeoff and landing and a long-distance route with long takeoff and landing respectively, to ensure that the route application simulates the operation of daily flights as much as possible, to ensure the authenticity and applicability of the application.

[0044] Furthermore, the preset route application qualification requirements include:

[0045] During the flight test, the engine did not experience any adverse operating conditions such as exceeding operating parameters, surging, slow acceleration, and / or speed hanging caused by the turbine lubricant. No adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were found during the entire line test. No engine component debris exceeding preset limits was found in the oil filter or magnetic plug.

[0046] After the test flight, the visual inspection results of the engine's TGB, AGB, IGB and lubricating oil system were normal, and no oil leakage related to the replaced test turbine lubricating oil was found in the engine and lubricating oil system related components;

[0047] The performance change trend of the tested turbine lubricating oil during the test flight meets the preset aircraft maintenance requirements.

[0048] Beneficial effects: The preset route application qualification requirements summarize the requirements for monitoring the operating parameters of the aircraft and engine during the test flight, as well as the requirements for disassembly and inspection of key components of the aircraft and engine lubricating oil systems after the test flight, and the requirements for lubricating oil performance change trends, etc., which improves the comprehensiveness of route application monitoring and the accuracy of judgment.

[0049] Furthermore, the preset flight time is at least 2000 hours.

[0050] Beneficial Effects: A preset flight duration of at least 2,000 hours prevents monitoring flights that are too short, potentially failing to fully detect negative impacts of the test oil on the aircraft and engine oil systems. For example, during normal route operation, the thermal oxidation stability and gas-liquid coking characteristics of turbine oils must exceed 1,500 flight hours before oxidation deposits or carbon coke products gradually form on components such as the engine's high-temperature bearing cavities, accessory gearboxes, and ventilation ducts. Shorter flight durations prevent a comprehensive and accurate assessment of the test turbine oil's overall performance.

[0051] Further, it also includes: promotion steps;

[0052] Promotion steps: Promote turbine lubricants that are judged to be airworthy and supervise the promotion process.

[0053] Beneficial effect: Improve subsequent supervision. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 1. A flow chart of an embodiment of a method for determining the airworthiness compliance of an aviation turbine engine lubricating oil according to the present invention;

[0055] Figure 2 Schematic diagram of the flow of an engine C cycle test in an embodiment of the method for determining the airworthiness compliance of an aviation turbine engine lubricant oil according to the present invention;

[0056] Figure 3 It is a structural schematic diagram of the VPC gas phase coking tester of the prior art;

[0057] Figure 4 This is a schematic structural diagram of the inner tube in Example 3 of the present invention;

[0058] Figure 5 This is a front view of the inner tube in Example 3 of the present invention;

[0059] Figure 6 This is a schematic structural diagram of a pipe joint in a third embodiment of the present invention;

[0060] Figure 7 This is a front cross-sectional view of a fourth embodiment of the present invention;

[0061] Figure 8 for Figure 1 Schematic diagram of the connection relationship between the sealing component, the box body and the main shaft;

[0062] Figure 9 Schematic diagram of the structure of the pinion gear in the FZG-AR gear pair in the fifth embodiment of the present invention;

[0063] Figure 10 Schematic diagram of the structure of the large gear in the FZG-AR gear pair in the fifth embodiment of the present invention;

[0064] Figure 11 Schematic diagram of the structure of the pinion gear in the FZG-CR gear pair in the fifth embodiment of the present invention;

[0065] Figure 12 Schematic diagram of the structure of the large gear in the FZG-CR gear pair in the fifth embodiment of the present invention;

[0066] Figure 13 This is the broken line graph of the loading load and gear bonding area before the gear fails in the test of test group 1;

[0067] Figure 14 This is the broken line graph of the loading load and gear bonding area before the gear fails in the test of test group 2;

[0068] Figure 15 This is the broken line graph of the loading load and gear bonding area before the gear fails in the test of test group 3;

[0069] Figure 16 This is the broken line graph of the loading load and gear bonding area before the gear fails in the test of test group 4;

[0070] Figure 17 This is the broken line graph of the loading load and gear bonding area before gear failure in test group 5;

[0071] Figure 18 This is a broken line graph of the loading load and gear bonding area before gear failure in test group 6. DETAILED DESCRIPTION

[0072] The following is further described in detail through specific implementation methods:

[0073] The reference numerals in the drawings of the specification include: three-necked flask 101, heating jacket 102, purified air supply subsystem 103, oil temperature indicating thermocouple 104, heating furnace 105, test tube 106, flat elliptical cylindrical pipe joint 107, cylindrical pipe joint 108, box 201, end cover 2011, oil outlet hole 2012, oil drain hole 2013, oil return hole 2014, main shaft 202, shoulder 2021, support bearing 203, test Test bearing 204, loading bearing 205, sealing assembly 2060, sealing assembly 2070, radial loading mechanism 208, baffle 1 2061, baffle 2 2062, baffle 3 2071, baffle 4 2072, recovery container 206, heating element 207, loading rod 2081, pressure rod 2082, pressure sensor 2083, weight 2084, locking nut 2010, gasket 2020, and fuel injector 2030.

[0074] Example 1

[0075] This embodiment is basically as shown in the attached Figure 1 As shown:

[0076] The airworthiness compliance determination method for aviation turbine engine lubricants includes the following:

[0077] CTSOA certification: Turbine lubricating oil is certified according to the standards. If it passes the certification, it will obtain CTSOA and undergo engine STC certification. If it fails the certification, the turbine lubricating oil will be deemed unairworthy. The standards are technical standards.

[0078] Specifically, CTSOA certification includes:

[0079] According to the requirements of CTSO-2C704, the chemical composition requirements and performance of the turbine lubricant are reviewed. If the review is passed, a CTSOA is obtained and the engine STC review is carried out. If the review is not passed, the turbine lubricant is deemed unairworthy.

[0080] The chemical composition review includes: determining whether the various components in the turbine lubricant meet the preset chemical composition requirements; the preset chemical composition requirements in this embodiment are that the turbine lubricant should be mainly based on polyol ester compounds, have a viscosity grade of 5 centistokes, should not use organic compounds containing barium and titanium, and if tricresol phosphate (TCP) additives are used, the mass fraction of the ortho isomer should not exceed 0.2%. All chemical components of the turbine lubricant should comply with the requirements of relevant national laws and regulations on environmental protection, toxicology, safety, etc., and a chemical safety data sheet or related documents should be established.

[0081] Certification of performance, including type inspection and quality control inspection;

[0082] Type inspection includes physical property tests, chemical property tests, stability performance tests, deposition performance tests, friction performance tests and additional tests on the turbine lubricating oil. Based on the test results, it is determined whether the turbine lubricating oil meets the type inspection requirements. If yes, a quality control inspection is carried out; if not, the turbine lubricating oil is deemed unairworthy.

[0083] The physical property tests in this embodiment include: kinematic viscosity (-40°C, 40°C and 100°C), viscosity stability, pour point, open flash point, evaporation loss, foam characteristics, shear stability and other items.

[0084] Chemical performance tests, including: total acid value, sediment / ash content, oil compatibility, rubber compatibility, trace metal content, etc.

[0085] Stability performance tests include: oxidation corrosion stability (175℃, 204℃, 218℃) and thermal stability corrosion tests.

[0086] Deposition performance tests include: dynamic coking test, high temperature bearing deposition performance test and gas phase coking test.

[0087] Friction performance tests, including: high-speed gear load capacity tests.

[0088] Additional tests include: monoacid composition, kinematic viscosity temperature curve (-55℃, -20℃, 0℃, 70℃, 150℃, 200℃ and 250℃), viscosity index, compression viscosity coefficient, density (-55℃, -20℃, 0℃, 15℃, 40℃, 70℃, 100℃, 150℃, 200℃ and 250℃), specific heat capacity (-55℃, -20℃, 0℃, 15℃, 40℃, 100℃, 150℃, 200℃ and 250℃), and the following parameters: ℃, 150℃, 200℃ and 250℃), thermal conductivity (40℃, 100℃, 150℃, 200℃ and 250℃), electrical conductivity, hydrolytic stability, oxidation stability, rubber compatibility (1800h), high temperature tube deposition, moderate wear, severe wear, heat aging performance (150℃, 180℃ and 225℃), particulate matter, ball-disc load capacity, rubber compatibility (test until rubber failure), etc.

[0089] Quality control inspection includes: when the turbine lubricating oil that has passed the type inspection is produced in batches, quality control inspection is carried out on no less than the preset batches of turbine lubricating oil to determine whether the turbine lubricating oil meets the quality control inspection requirements. If so, it passes the certification to obtain CTSOA and perform engine STC certification; if not, the turbine lubricating oil is judged to be unairworthy; the quality control inspection includes: kinematic viscosity (-40℃ and 40℃), pour point, open flash point, foam characteristics, total acid value, sediment / ash, trace metal content, oxidation corrosion stability (204℃), thermal stability corrosion, dynamic coking and gas phase coking tests. The preset batches are at least 3 times;

[0090] For turbine lubricants that have passed the review and obtained CTSOA, each batch of turbine lubricants produced thereafter shall undergo quality control inspection, and the qualified inspection data shall be filled in the turbine lubricant product quality certificate for its quality handover, as shown in Table 1:

[0091] Table 1 Turbine Lubricating Oil Product Quality Certificate

[0092]

[0093]

[0094]

[0095] Engine STC certification: The turbine lubricating oil is tested on an engine test bench for no less than a preset number of C cycles. If the test passes, the oil is awarded an STC and can be used on a route. If the test fails, the oil is deemed unairworthy. In this embodiment, the engine test bench is a full-scale ground-based aviation turbofan engine test bench.

[0096] Specifically, the engine test bench includes: a test engine and an engine oil system framework;

[0097] The test engine includes: fan, low-pressure compressor, high-pressure compressor, annular combustion chamber, high-pressure turbine, low-pressure turbine and exhaust system; the remaining life of the test engine should be no less than 50% of its service life;

[0098] The engine oil system structure includes: oil tank, oil pump, oil filter, fuel / oil heat exchanger, anti-leakage valve, oil collection device, oil quantity / temperature sensor, oil pressure sensor, oil filter bypass switch, magnetic chip metal detector and oil pipeline; the engine oil system structure is a self-closed system, the main function of which is to provide lubrication and cooling for the engine bearings, gears and seals, and at the same time perform heat exchange with the test engine to heat the fuel supplied to the annular combustion chamber and servo actuator system.

[0099] Engine STC certification, including:

[0100] The engine test bench must be drained, cleaned, and maintained. Specifically, before the first ground test, the test engine must be re-installed with the turbine oil to be tested. Prior to re-installation, the engine oil system, starter, and internal gear box (IDG) must be drained, cleaned, and maintained to ensure the test engine is fully re-installed with domestically produced lubricants. During operation, the engine oil system, starter, and IDG must be cleaned and the turbine oil replaced according to the AMM manual.

[0101] Replace the turbine oil on the engine test bench;

[0102] Conduct engine C cycle test; the number of cycles shall not be less than the preset C cycle number;

[0103] like Figure 2 As shown, the specific C cycle test of the engine is as follows:

[0104] a. Record the ambient temperature. This can be obtained by measuring the nose landing gear well temperature with a portable thermometer or from the control tower (if the ambient temperature has been recorded within 2 hours before the current start-up, the previously recorded temperature can be used for this C cycle);

[0105] b. Find the N1 of the maximum continuous thrust level and the maximum reverse thrust level of the test engine at the corresponding temperature, and the N2 of the air idle thrust level;

[0106] c. Start the test engine normally using the APU or an external bleed air source (do not start using cross-bleed air), and record the test engine start-up time;

[0107] d. Stabilize the engine at idle speed on the ground for 120 seconds. After the test engine parameters are stable and before the next throttle lever operation, record the engine parameters as required (including N1 speed, N2 speed, oil pressure, oil temperature, N1 vibration, N2 vibration, and oil quantity, which will not be repeated below);

[0108] e. Confirm that the ATTCS inhibit button is pressed, adjust the test engine thrust to TO / GA, and maintain it for 90 seconds. After the test engine parameters stabilize and before the next throttle lever operation, record the engine parameters as required;

[0109] f. Operate the throttle lever to set the maximum continuous thrust level (N1) as the target value, adjust the test engine to the maximum continuous thrust level, and maintain this level for 90 seconds. After the test engine parameters stabilize and before the next throttle lever operation, record the engine parameters as required;

[0110] g. Use the throttle lever to set the test engine to the air idle thrust level with N2 as the target value and maintain this level for 100 seconds.

[0111] h. Use the throttle lever to set the maximum reverse thrust level, N1, as the target value, and adjust the test engine to the maximum reverse thrust level (simulate by using N1 speed under forward thrust, do not adjust the throttle lever to the reverse position) and hold for 20 seconds;

[0112] i. Adjust the test engine to the ground idle thrust level and maintain it for 300 seconds. When the test engine parameters are stable and before shutting down, record the engine parameters as required. Then shut down the engine and record the engine shutdown time.

[0113] j. After shutting down the engine, wait for 120 seconds;

[0114] k. Repeat from step a until all 2000 cycles of testing are completed.

[0115] During the engine C cycle test, engine operation data is collected and analyzed, and turbine oil consumption is monitored and sampled for analysis. A graduated cylinder is used for measurement each time turbine oil is added or extracted. Turbine oil is added to the oil tank according to the AMM manual only after the engine has been shut down for more than 15 minutes (but not more than 30 minutes). Sufficient turbine oil is added until the liquid level reaches the "FULL" mark on the oil tank level observation window. Each time a sample is taken, turbine oil is lost, or turbine oil is added, the oil sampling log and consumption are recorded according to Table 2 below. The recommended time interval for adding turbine oil during ground testing is 25 hours of net engine operation time or when the oil volume drops to 1 / 3 of the "FULL" scale.

[0116] Table 2 Lubricating oil sampling log and consumption record

[0117]

[0118] Note: As shown in the table above, “Total Running Time” is the cumulative running time of the engine after the turbine oil to be tested is replaced; “Net Engine Running Time” is the cumulative running time since the engine was last added with turbine oil; “Net Oil Increase” is the amount of turbine oil added this time minus the total amount of samples taken and the total oil loss since the last addition of turbine oil; “Oil Consumption Rate” is the net increase of turbine oil divided by the net running time of the engine, calculated each time turbine oil is added except for the first time.

[0119] After the engine C cycle test, perform oil sampling analysis, visual inspection and disassembly inspection;

[0120] The oil sampling operation in the oil sampling analysis shall refer to the AMM manual;

[0121] The visual inspection is as follows: Open the fan cowl and follow the Fan cowl - Open procedure in the AMM manual. Visually inspect the test engine's TGB, AGB, IGB, and engine oil system structure, and record any oil leaks. Inspect and record the center vent pipe for coking. Upon completion of the inspection, follow the Fan cowl - Close procedure in the AMM manual, return the aircraft to normal operation, and remove all tools, equipment, and irrelevant items from the work area.

[0122] The disassembly inspection is as follows: After the ground cycle test is completed, the oil filter and magnetic chip metal detector are removed from the engine according to the AMM manual, cleaned and the quality of the debris (non-magnetic debris and magnetic debris) is collected, and the debris is subjected to physical and chemical quantitative analysis. The O-rings of the oil filter and magnetic chip metal detector are checked for abnormal phenomena such as corrosion or cracks. The central ventilation pipe outlet area is visually inspected and photographed (to confirm whether there is coking and the coking location) to evaluate the working condition of the engine.

[0123] Based on the engine operation data collection and analysis results, sampling analysis results, visual inspection results, and disassembly inspection results, determine whether each result meets the preset engine STC certification requirements. If so, obtain the STC and implement route application; if not, determine that the turbine lubricating oil is unairworthy;

[0124] The preset engine STC certification requirements include:

[0125] The change trends of various parameters of the engine equipped with the test turbo lubricant over the cycle number are consistent with those of the reference turbo lubricant, with no obvious mutations; the reference turbo lubricant is a commercial turbo lubricant;

[0126] During the engine C-cycle test, the test engine exhibited no adverse operating conditions such as parameter out-of-limit, surge, slow acceleration, and / or speed hang caused by the turbine lubricant. During the engine STC certification, no adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were observed. No engine component debris exceeding the preset limits was found in the oil filter or magnetic plug. The preset limits are those specified in the engine manual.

[0127] After the engine C cycle test, the visual inspection results of the test engine's TGB, AGB, IGB and lubricating oil system were normal, and there was no oil leakage related to the replacement of turbine lubricating oil in the test engine and related components of the lubricating oil system.

[0128] In this embodiment, the preset number of C cycles is at least 2000 times.

[0129] Route application: Turbine oil is applied to designated aircraft and designated routes for a period of not less than the preset flight hours, and the application is monitored. If the monitoring application passes, the turbine oil is deemed airworthy; if it fails, the turbine oil is deemed unairworthy. The monitoring application includes: monitoring changes in aircraft engine operating parameters and sampling and analyzing the turbine oil to determine whether the turbine oil meets the preset requirements. If so, the turbine oil is deemed airworthy; if not, the turbine oil is deemed unairworthy.

[0130] Specifically, route application includes: applying turbine lubricating oil to designated aircraft models and designated routes, and conducting route application tests;

[0131] A single test includes: replacing the test turbine oil and reference turbine oil in the engines on both sides of the test aircraft, respectively, and conducting two flight segments of testing, where the flight times of the two segments are not less than a first preset flight time and a second preset flight time, respectively. The two segments are a short-range route with short takeoffs and landings, and a long-range route with long takeoffs and landings. In this embodiment, the first preset flight time is not less than 1.3 flight hours, and the second preset flight time is not less than 2.1 flight hours. Each flight segment includes the following phases: takeoff, climb, cruise, descent, and landing, and the cruise altitude is required to be not less than 30,000 feet.

[0132] Collect and record the operating data of the aircraft and engine in each flight segment during the test flight;

[0133] Sampling and analysis of turbine oil in engines, starters and IDGs on both sides;

[0134] Conduct visual and disassembly inspections of the engine oil filter and metal chip sensor;

[0135] Based on the comparative analysis of the flight test data collected and recorded for each flight segment, visual inspection results, test oil sampling and analysis, and disassembly inspection results, determine whether the test is qualified. If so, proceed to the next test; if not, determine that the turbine oil is not airworthy.

[0136] After the visual inspection and sampling analysis are completed, the test engine will be replaced with the original commercial turbine oil as needed, and the engine oil system, starter and IDG will be cleaned and maintained to restore the engine to an airworthy state;

[0137] The number of tests is determined based on the total flight time of the test being no less than the preset flight time, and it is judged whether each test meets the preset route application qualification requirements. If so, the turbine lubricant is determined to be airworthy; if not, the turbine lubricant is determined to be unairworthy.

[0138] The pre-set eligibility requirements for routes include:

[0139] During the flight test, the engine did not experience any adverse operating conditions such as exceeding operating parameters, surging, slow acceleration, and / or speed hanging caused by the turbine lubricant. No adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were found during the entire line test. No engine component debris exceeding preset limits was found in the oil filter or magnetic plug.

[0140] After the test flight, the visual inspection results of the engine's TGB, AGB, IGB and lubricating oil system were normal, and there was no oil leakage related to the turbine lubricating oil used in the replacement test on the engine and the related parts of the lubricating oil system;

[0141] The performance change trend of the tested turbine lubricant during the test flight meets the preset aircraft maintenance requirements, where the preset aircraft maintenance requirements are the requirements of the aircraft maintenance manual.

[0142] In this embodiment, the preset flight time is at least 2000 hours;

[0143] Promotion steps: Promote turbine lubricants that are judged to be airworthy and supervise the promotion process.

[0144] This program begins with turbine oil testing and progresses through CTSOA certification, engine STC certification, and line application certification, concluding at the operational level. This program encompasses the entire spectrum of turbine oil compliance with airworthiness regulations and standards, including laboratory testing, full-scale ground-based aircraft turbofan engine bench testing, and line application monitoring testing. This ensures compliance of various turbine oil performance parameters with airworthiness regulations and technical standards. Each airworthiness certification step must be completed before proceeding to the next airworthiness certification step. CTSOA certification verifies the turbine oil's compliance with standard specifications according to technical standards. Engine STC certification involves conducting engine bench testing for no fewer than a predetermined number of cycles to determine the turbine oil's compliance with the engine model design. Line application monitoring certification involves conducting operational flight monitoring for no fewer than a predetermined number of hours to determine the turbine oil's compliance with aircraft and engine line operating requirements, thereby ensuring the accuracy and completeness of the airworthiness certification.

[0145] In summary, carrying out the airworthiness certification and verification of turbine lubricants in accordance with the requirements of this plan can determine the compliance of turbine lubricants with airworthiness regulations and technical standards, and ensure the accuracy and completeness of the judgment.

[0146] Example 2

[0147] This embodiment is substantially the same as the first embodiment, except that, in this embodiment, considering the high cost and complexity of engine bench testing, in order to reduce engine bench testing time and lower the cost of engine STC certification, prior to engine STC certification, laboratory analysis and testing are first conducted to compare and analyze the domestically produced turbine oil to be tested with an approved imported turbine oil (also known as a reference turbine oil, generally a mainstream commercial turbine oil from abroad). Based on the comparative analysis results, the engine STC certification can be adjusted, thereby reducing engine bench testing time and lowering the cost of engine STC certification.

[0148] Specifically, as shown in Table 3, according to the corresponding clauses of the Aircraft Engine Airworthiness Regulations (CCAR-33-R2), the corresponding conformity verification methods are adopted to implement the corresponding conformity verification ideas;

[0149] Table 3 Conformity Verification

[0150]

[0151]

[0152]

[0153]

[0154] Through the solution of this embodiment, the preset number of C cycles can be reduced by at least 50%. That is, compared with the solution of embodiment 1, the preset number of C cycles in this embodiment is at least 1000 times, thereby reducing the test time of the engine bench and reducing the cost of engine STC certification.

[0155] Example 3

[0156] The gas-phase coking test described in Example 1 is for turbine oil. Turbine oil primarily serves to lubricate and cool components within aircraft engines. Under the high-temperature operating conditions of an engine, turbine oil is susceptible to oxidation and cracking. Oxidized or cracked turbine oil produces byproducts, such as carbon deposits and sludge, that severely impact engine performance. These byproducts can impede the proper functioning of bearings, gears, seals, scavenge pumps, and the intake system. In severe cases, they can lead to catastrophic engine failure, compromising aircraft safety.

[0157] While existing aircraft turbine engines are mostly lubricated with turbine lubricants based on neopentyl polyol esters, these synthetic ester aviation lubricants offer excellent thermal stability and antioxidant properties, allowing for operation over a wide temperature range. Compared to synthetic diester-based lubricants, neopentyl polyol ester-based turbine lubricants offer longer change intervals, lower oil loss, and significantly reduced sludge and carbon deposit formation.

[0158] However, as the demand for aircraft turbine engines changes and develops, they need to become lighter and more compact while producing greater power. This requires increasing the unit "energy density" of aircraft turbine engines, thereby generating greater thrust while reducing engine size and weight. However, as the engine's unit "energy density" increases, the temperature before the engine turbine will also increase significantly, causing the surface of the engine components that the turbine lubricant contacts to reach higher temperatures. This will cause the currently widely used neopentyl polyol ester turbine lubricant to undergo high-temperature oxidation or thermal cracking reactions, generating large amounts of harmful carbon deposits or sludge.

[0159] Therefore, the development and production of turbine lubricants suitable for high-temperature operating conditions is urgent. Furthermore, as a key component of aircraft turbine engines, the quality and performance of lubricants are closely linked to the safe operation of these engines. Therefore, any turbine lubricant must undergo airworthiness certification, demonstrating compliance with applicable regulations and technical standards, before it is approved for use on civil aircraft. Airworthiness verification of turbine lubricant performance requires measuring the tendency of the steam-air mixture of the turbine lubricant to undergo high-temperature oxidation or thermal cracking reactions on the surfaces of hot-end components, such as the engine vent pipes, under high-temperature heat-immersion conditions. Specifically, the China Civil Aviation Technical Standard for Civil Aviation, "Civil Aviation Engine Lubricants" (CTSO-2C704), specifies that turbine lubricants must undergo a vapor-phase coking test to determine the lubricant's tendency to form carbon deposits in the non-oil-wetted, high-temperature vent pipes of aircraft turbine engines.

[0160] The gas phase coking tendency of existing turbine lubricating oil is mainly measured by VPC gas phase coking tester; VPC gas phase coking tester mainly consists of three-necked flask, purified air system part, heating furnace test part, insulation test tube part and control cabinet. For details, please see Figure 3 shown.

[0161] The test process is as follows: In a three-necked flask (such as Figure 3 Add an appropriate amount of the turbine oil sample to be tested into the test tube and use a suitable heating jacket (as shown in Figure 1). Figure 3 2) to heat the turbine oil sample in the three-necked flask to 204°C, and at the same time, the purified air supply subsystem (as shown in FIG. Figure 3 3) to continuously add 765±5mL / min of dry purified air into the three-necked flask, making it a medium to carry away the turbine lubricating oil sample vapor and provide an oxidant (oxygen) for the turbine lubricating oil sample vapor to oxidize and coke at high temperature. The temperature of the three-necked flask is determined by the oil temperature indicator thermocouple (as shown in Figure 3) inserted below the oil level in the flask. Figure 3 The oil temperature indicating thermocouple adjusts the power of the spherical electric heating jacket according to the temperature fluctuation in the three-necked flask, thereby controlling the temperature of the three-necked flask. Then the mixed gas of the turbine lubricating oil sample steam and the dry purified air enters the heating furnace above the three-necked flask (as shown in Figure 3 5), the heating furnace heats the mixed oil sample steam passing through its channel through a high-power heating coil (1200W), and also heats the test tube (such as Figure 36) to maintain the specified test temperature range, typically 371°C. Similar to the temperature control method for the three-necked flask, the heating furnace uses thermocouples to determine temperature fluctuations, thereby controlling the power of the heating coils in the furnace to maintain a stable test temperature. A mixture of turbine oil sample vapor and dry, purified air is heated in the furnace and then enters a test tube embedded in the furnace. The bottom of the test tube is securely fastened to the furnace with a tightening nut, maintaining a test temperature of approximately 371°C.

[0162] At the same time, six thermocouples were installed on the test tube at equal distances from the bottom to the top to monitor and record temperature changes at different locations on the stainless steel test tube. This is because only a small portion of the bottom tube (approximately 1 cm) is inserted into the heating furnace. The remaining tube is far away from the heating furnace, resulting in a temperature gradient along the axial direction of the stainless steel test tube, resulting in a high temperature near the end of the heating furnace and a low temperature at the end far away from the heating furnace. When the turbine lubricating oil test steam passes through the test tube, as the test tube temperature continues to decrease, when the lubricating oil steam cools to a certain temperature, it will condense into liquid and flow back down along the inner wall of the test tube until it returns to a specific temperature. Under the action of high temperature and oxygen in the air, the lubricating oil gradually forms sludge and carbon deposits on the inner wall of the test tube. At this time, the temperature of the lubricating oil steam coke is measured by the six thermocouples on the outer surface of the test tube and the location of the sludge and carbon deposits formed in the tube.

[0163] When all control parameters of the gas phase coking tester are stable, the 18-hour test begins.

[0164] During a large number of tests conducted on a self-built gas phase coking tendency test bench, the inventors discovered that the existing VPC gas phase coking tester had a number of problems:

[0165] 1. The test tube specified by foreign standards is a single-layer cylindrical tube with a diameter of 12.7 mm. The heat loss of the single-layer test tube is fast and is easily affected by the ambient temperature conditions;

[0166] 2. Foreign standards require that the thermocouple on the outside of the single-layer test tube be installed with a metal clamp, and the thermocouple wire tube is welded to the outside of the clamp, resulting in the outer diameter of the single-layer test tube assembly increasing to more than 30mm. At the same time, in order to prevent the thermocouple metal wire from contacting the inner wall of the insulation sleeve, increase measurement accuracy, and prevent wear of the thermocouple metal wire, the inner diameter of the insulation sleeve will be increased to at least 40mm. This results in a large gap between the inner wall of the insulation sleeve and the single-layer test tube, which is easily affected by ambient temperature conditions, causing a large amount of heat loss in the single-layer test tube, resulting in an uneven temperature distribution gradient along the axial direction of the single-layer test tube, seriously affecting the repeatability and reproducibility of the test;

[0167] 3. The single-layer cylindrical shape with a diameter of 12.7 mm does not conform to the double-layer flat elliptical cylindrical structure of domestic aviation turbine engine ventilation pipes, and its simulation authenticity is low;

[0168] 4. Through extensive testing, the inventors discovered that the coking temperature range of standard aviation turbine lubricants inside the test tube is mostly concentrated between 170°C and 270°C, while that of high-performance aviation turbine lubricants is mainly concentrated between 190°C and 240°C. However, the existing VPC gas-phase coking tendency tester has only six thermocouples on the test tube, evenly distributed from the bottom to the top of the test tube. This limits the coking temperature range of different types of aviation turbine lubricants and makes it impossible to accurately measure the gas-phase coking temperature range of different aviation turbine lubricants, affecting the test accuracy.

[0169] 5. The heating temperature of the three-necked flask is 204°C, which cannot adapt well to the hot soaking temperature of the high-temperature bearing cavity of low-power and high-power domestic aviation turbine engines, making the simulation less realistic;

[0170] The above problems will directly or indirectly lead to large differences in key parameters such as the quality of gas phase coking deposits, the temperature distribution of carbon deposits and paint films formed in the test tube, and the maximum generation temperature of carbon deposits in multiple tests of the same turbine lubricant, which seriously affects the accuracy of the determination of the gas phase coking tendency of turbine lubricants, resulting in low repeatability and reproducibility of the determination of the gas phase coking tendency of turbine lubricants, and the inability to guarantee the accuracy of the determination of the gas phase coking tendency of turbine lubricants, thereby failing to obtain accurate gas phase coking characteristics of turbine lubricants, making the referenceability of the determination results low. The development of existing domestic turbine lubricants cannot refer to the determination results of the gas phase coking tendency of turbine lubricants to design turbine lubricants, which greatly hinders the development and production of domestic turbine lubricants and restricts the airworthiness certification of turbine lubricants in my country; at the same time, it also makes it impossible for the development of existing domestic engines to accurately design the size, material and configuration of the engine high-temperature bearing cavity ventilation duct according to the gas phase coking characteristics of the lubricant, which greatly limits the research and development of domestic engines. Therefore, a turbine oil gas phase coking tendency determination system is proposed in this embodiment, as follows:

[0171] This embodiment is basically the same as the above embodiment, except that it further includes:

[0172] The gas phase coking test uses a turbine oil gas phase coking tendency determination system independently developed by the inventors.

[0173] It includes a test tube 106, a three-necked flask 101, a heating jacket 102, a purified air supply subsystem 103, a heating furnace 105 and a control subsystem;

[0174] The test tube 106 comprises an inner tube, an outer tube and a tube joint;

[0175] The inner tube is arranged inside the outer tube with a gap between the inner and outer tubes, and both the inner and outer tubes are flat elliptical cylindrical tubes; one end of the pipe joint is a flat elliptical cylindrical tube joint 107, and the other end is a cylindrical tube joint 108; the flat elliptical cylindrical tube joint 107 is used to connect the inner and outer tubes, and the cylindrical tube joint 108 is used to install the test tube 106;

[0176] Specifically, the material of the test tube 106 is MAS7101 standard GH625 steel;

[0177] The inner tube shape is as follows Figure 4 、 Figure 5 As shown, it is a flat elliptical cylindrical tube, which is welded by two semicircular tubes and two flat plates. The surface roughness range is 2.0-5.0, the long end range is 20-50, and the round surface profile range is 0.1-0.4; the upper and lower sides are two semicircular tubes, with an outer diameter range of 15-20mm, a thickness range of 0.5-2.0mm, and a length range of 100-200mm; the flat plate length range is 100-200mm, the thickness range is 0.5-2.0mm, and the width range is 10-25mm;

[0178] The outer tube has the same shape as the inner tube, which is a flat elliptical cylindrical tube welded by two semicircular tubes and two flat plates. The surface roughness range is 2.0-5.0, the long end range is 20-55, and the round surface profile range is 0.1-0.4; the upper and lower edges are two semicircular tubes with an outer diameter range of 18-30mm, a thickness range of 0.5-2.0mm, and a length range of 150-250mm; the flat plate has a length range of 150-250mm, a thickness range of 0.5-2.0mm, and a width range of 10-25mm.

[0179] Pipe fittings such as Figure 6 As shown, the size of the inner layer tube can be converted into a cylindrical pipe joint with a length range of 18-30mm, an outer diameter range of 8-20mm, and a thickness range of 0.8-2.0mm; the maximum cross-sectional length and width of the pipe joint are both less than 50mm;

[0180] The total length of the inner pipe and the pipe joint is in the range of 150-250 mm, and the total length of the outer pipe is in the range of 150-250 mm.

[0181] The test tube 106 is provided with a plurality of thermocouples from the bottom to the top for monitoring temperature changes at different locations on the test tube 106. In this embodiment, the number of thermocouples is 10, and the specific locations are shown in Table 4 below:

[0182] Table 4 Installation parameters of thermocouple on test tube 106

[0183]

[0184] Thermocouples 1#, 3#, 5# and 7# are newly added compared to the six thermocouples provided in the prior art, and all thermocouples are connected to the control subsystem.

[0185] The thermocouple conductor uses a flexible thermocouple wire with a diameter less than or equal to a preset diameter and is connected to the inner tube by welding. The thermocouple conductor uses a flexible thermocouple wire with a diameter less than or equal to a preset diameter. The preset diameter is set according to demand, and the preset diameter is generally a small diameter. Because the small-diameter flexible thermocouple wire requires less space, and is connected to the inner tube by welding, the gap between the inner and outer tubes is greatly reduced. The air layer in the gap not only provides a certain degree of insulation, but also prevents heat loss caused by excessive gaps. The insulation sleeve can cover the test tube, further reducing heat loss within the test tube and preventing wear of the thermocouple conductor. In this embodiment, the preset diameter is less than or equal to 1 mm.

[0186] An oil temperature indicating thermocouple 104 is provided in the three-necked flask 101 for monitoring the temperature change of the turbine lubricating oil in the three-necked flask 101. The oil temperature indicating thermocouple 104 is connected to the control subsystem through the neck opening on one side of the three-necked flask 101. Specifically, the oil temperature indicating thermocouple 104 is installed in the thermocouple adapter, the black plastic fixing nut on the top of the thermocouple adapter is tightened, and the assembled thermocouple adapter is then inserted into the neck opening of the three-necked flask 101 so that the outer wall and the neck opening are tightly sealed and the oil temperature indicating thermocouple 104 is located in the middle of the three-necked flask 101. The thermocouple adapter is a frosted glass adapter. In this embodiment, both the thermocouple and the oil temperature indicating thermocouple 104 are J-type thermocouples with 304 stainless steel housings, are ungrounded, and have double connectors.

[0187] The neck opening on the other side of the three-necked flask 101 is connected to the purified air supply subsystem 103. Specifically, the neck opening on the other side of the three-necked flask 101 is connected to the purified air supply subsystem 103 via an air inlet pipe. The PTFE sealing diaphragm is inserted into the conical ground mouth of the air inlet pipe. The air inlet pipe is inserted into the neck opening. When inserted, it is rotated downward and left and right to ensure that the air inlet pipe is in close contact with the neck opening.

[0188] The neck of the three-necked flask 101 is connected to the heating furnace 105. Specifically, the metal tube below the heating furnace 105 is inserted into the neck of the three-necked flask 101 through the adapter, and the adapter and the end of the metal tube are in close contact.

[0189] The test tube 106 is coated with an insulation layer and is longitudinally arranged in the heating furnace 105 and communicates with the neck opening in the middle of the three-necked flask 101. Specifically, the test tube 106 is longitudinally arranged in the heating furnace 105 with the pipe joint facing downward, and the cylindrical pipe joint 108 of the pipe joint is inserted into the metal pipe of the heating furnace 105 for fixed connection.

[0190] A three-necked flask 101 is used to hold turbine lubricating oil; in this embodiment, the three-necked flask 101 has a capacity of 2000 mL;

[0191] The heating jacket 102 is used to heat the three-necked flask 101, and the temperature during heating is set to 220°C; the heating jacket 102 is connected to the control subsystem; in this embodiment, the heating jacket 102 adopts a spherical temperature bag stand to support the three-necked flask 101;

[0192] The purified air supply subsystem 103 is used to add air to the three-necked flask 101. Specifically, when the purified air supply subsystem 103 injects air into the turbine lubricating oil in the three-necked flask 101, the air flow rate is controlled at 765±5 mL / min by a rotameter and a mass flow controller. To ensure dryness, an air gas purifier is also used.

[0193] The heating furnace 105 is used to heat the test tube 106, wherein the heating temperature includes one or more of 288° C., 325° C., 343° C., 371° C., 399° C., and 412° C. The heating furnace 105 is connected to the control subsystem; the heater coils in the heating furnace 105 are 220 volts and 1200 watts respectively;

[0194] The control subsystem is used to collect and process data from the heating jacket 102, the heating furnace 105, the thermocouple, and the oil temperature indicating thermocouple 104, and adjust the heating temperature of the heating jacket 102 and the heating furnace 105 based on the collected data. Specifically, the control subsystem includes:

[0195] Data acquisition controller, used to read J-type thermocouple, with a sensitivity of 1°C and can be used continuously for more than 20 hours;

[0196] Heating jacket 102 controller, used to design time variable, heating and constant temperature controller, single loop, input J-type thermocouple, output relay or contact, can accurately control within 1℃;

[0197] Heating furnace 105 controller, used for setting time, heating and constant temperature, single loop, input J-type thermocouple, output relay or contact, can be accurately controlled within 1°C;

[0198] The heating jacket 102 power controller includes: a silicon controlled rectifier (SCR) for receiving an input from the heating jacket 102 controller;

[0199] The heating furnace 105 power controller is used to receive the heating furnace 105 controller input.

[0200] The specific measurement process, using the turbine lubricating oil gas phase coking tendency measurement system mentioned above, includes the following:

[0201] Equipment preparation steps: Clean all components in the turbine lubricating oil gas phase coking tendency determination system;

[0202] Initial data measurement steps: Obtain the 40°C kinematic viscosity and total acid number of the turbine lubricant to be tested, the initial weight of the test tube 106, and the initial weight of the three-necked flask 101 containing the turbine lubricant to be tested; Specifically, the 40°C kinematic viscosity and total acid number of the turbine lubricant to be tested having a first preset weight are measured using the GB / T 265 and GB / T 7304 methods, respectively; A second preset weight of the turbine lubricant to be tested is added to the three-necked flask 101, and the initial weights of the test tube 106 and the initial weight of the three-necked flask 101 containing the turbine lubricant to be tested are measured using an analytical balance to an accuracy of 0.1 mg and 0.1 g, respectively;

[0203] Test steps: Test the turbine lubricating oil for a preset time at a plurality of preset heating furnace 105 heating temperatures using the turbine lubricating oil gas phase coking tendency determination system; specifically,

[0204] Connecting various components in the turbine lubricating oil gas phase coking tendency determination system;

[0205] At a plurality of preset heating temperatures of the heating furnace 105, the heating jacket 102 heats the three-necked flask 101, and the heating furnace 105 heats the test tube 106. The purified air system adds air to the three-necked flask 101. During the heating process, the control subsystem adjusts the heating temperature of the heating jacket 102 and the heating furnace 105 based on the data of the thermocouple and its first preset temperature value and the data of the oil temperature indicating thermocouple 104 and its second preset temperature value. In this embodiment, the second preset temperature value is 220°C.

[0206] The preset heating temperature of the heating furnace 105 includes one or more of 288°C, 325°C, 343°C, 371°C, 399°C and 412°C;

[0207] After all the preset heating furnaces 105 have completed the heating time test at the preset temperature, the heating is stopped and the cooling is performed. In this embodiment, the preset heating time of each preset heating furnace 105 is 6 hours.

[0208] After cooling, disassemble the components of the turbine lubricating oil gas phase coking tendency determination system. When disassembling the three-necked flask 101, carefully remove the intake pipe to allow the turbine lubricating oil in the intake pipe to fully flow back into the three-necked flask 101. Then, remove the oil temperature indicating thermocouple 104 to allow the test oil attached to the oil temperature indicating thermocouple 104 to fully flow back into the three-necked flask 101.

[0209] Dry the test tube 106; specifically, immerse the test tube 106 in petroleum ether for at least 30 minutes, then place the test tube 106 in an oven and dry it at 100°C for at least 30 minutes. After drying, place the insulated test tube 106 in an airtight storage tube, and then place the airtight storage tube in a drying oven to allow the test tube 106 to cool naturally to room temperature.

[0210] Final data measurement steps: Obtain the kinematic viscosity at 40°C, total acid number, final weight of the test tube 106, and final weight of the three-necked flask 101 containing the tested turbine lubricant after the test; the same method as the initial data measurement steps is used to obtain these data, and will not be repeated in this embodiment;

[0211] Data analysis steps: Obtain the weight of the coke based on the initial weight and final weight of the test tube 106; Obtain the consumption of the turbine lubricating oil based on the initial weight and final weight of the three-necked flask 101; Obtain the change in kinematic viscosity and total acid value based on the comparison results of the 40°C kinematic viscosity and total acid value of the tested turbine lubricating oil with the 40°C kinematic viscosity and total acid value of the tested turbine lubricating oil; Specifically, the weight of the coke M3 = M2 - M1, where M1 is the initial weight of the test tube 106; M2 is the final weight of the test tube 106;

[0212] The consumption of the turbine lubricating oil m5 = m4 - m3, wherein m3 is the initial weight of the three-necked flask 101 containing the turbine lubricating oil to be tested; m4 is the final weight of the three-necked flask 101 containing the turbine lubricating oil after the test;

[0213] The kinematic viscosity change rate % = [(V2-V1) / V1] x 100%, where V1 is the kinematic viscosity of the turbine oil to be tested at 40°C, mm 2 / s; V2 is the kinematic viscosity of the turbine oil at 40°C after the test, mm 2 / s;

[0214] The total acid value change value=TAN2-TAN1, wherein TAN1 is the total acid value of the turbine lubricating oil to be tested, mgKOH / g; TAN2 is the total acid value of the turbine lubricating oil after the test, mgKOH / g.

[0215] Specifically, the experimental results of the experiments using the existing method and this solution are as follows:

[0216] Table 5 Test results of test tube 106 using the original standard requirements

[0217]

[0218]

[0219] Note: All the above tests were completed under the conditions of 204℃ turbine oil temperature, 371℃ test tube 106 heating furnace 105 temperature, 765mL / min air flow rate and 18h test time.

[0220] Table 6 Test results using modified test tube 106

[0221]

[0222] Note: All the above tests were completed under the conditions of 204℃ turbine oil temperature, 371℃ test tube 106 heating furnace 105 temperature, 765mL / min air flow rate and 18h test time.

[0223] It can be clearly seen from Tables 5 and 6 that the differences in the coke weight, turbine oil consumption, kinematic viscosity, and total acid number obtained from multiple experiments on the same turbine oil are smaller than those of the prior art. In addition, the measurement range for standard aviation turbine oil and high-performance aviation turbine oil is more accurate. Therefore, this scheme can improve the test accuracy, thereby enhancing the repeatability and reproducibility of the gas phase coking tendency measurement.

[0224] The improvement of repeatability and reproducibility, combined with the fact that the shape of the test tube in the turbine lubricating oil gas phase coking tendency determination system is consistent with the double-layer flat elliptical cylindrical structure of the domestic aviation turbofan engine ventilation tube, and the temperature gradient distribution of carbon deposits and paint films formed in the test tube is uniform, ensures the accuracy of the determination of turbine lubricating oil gas phase coking, thereby obtaining accurate turbine lubricating oil gas phase coking characteristics, making the reference value of the measurement results improved.

[0225] The research and development of existing domestically produced turbine lubricants can refer to the test results of the gas phase coking tendency of turbine lubricants to design turbine lubricants, promote the research and development of domestically produced turbine lubricants, and make the developed domestically produced turbine lubricants more suitable for domestically produced engines;

[0226] At the same time, the development of existing domestic engines can be carried out through model design and parameter adjustment based on the gas-phase coking characteristics of turbine lubricants. For example, after clarifying the gas-phase coking characteristics of various domestic turbine lubricants, domestic turbine lubricants can be selected according to demand, and based on the gas-phase coking tendency measurement results of domestic turbine lubricants, the engine high-temperature bearing cavity ventilation pipe size, material and configuration can be accurately designed to ensure that domestic engines have optimal performance when using the selected domestic turbine lubricants, thereby improving the forward design capabilities of my country's aviation engines.

[0227] Example 4

[0228] The high-temperature bearing deposition performance test described in Example 1 uses an aviation lubricant oil deposition performance test device. Existing aviation lubricant oil deposition performance test devices have many problems, specifically:

[0229] Turbine lubricating oil is a part of aviation fuel. It mainly provides lubrication, cooling and cleaning for key moving parts such as ball bearings, roller bearings and gears. It is an indispensable functional material for various systems of aircraft and turbofan engines.

[0230] Take the turbine oil used in aircraft turbine engines as an example. Through the lubrication system, turbine oil effectively lubricates the high-temperature moving components within the turbine engine while also removing significant heat from these components, keeping them relatively cool and maintaining stable operation at an appropriate operating temperature. Furthermore, during recycling, the turbine oil removes impurities from the engine, effectively cleaning the turbine engine. However, within the lubrication system, turbine oil is continuously recycled. Throughout this cycle, it undergoes a repetitive cycle of heat absorption, temperature rise, oxidation, and cooling, leading to its tendency to evaporate, coke, and corrode. Therefore, it is necessary to study and evaluate the high-temperature oxidation stability and anti-wear properties of turbine oil.

[0231] In the prior art, turbine lubricating oil needs to be tested using a method that meets the FED-STD-791E Method 3410 standard method or an equivalent alternative method (hereinafter referred to as the "deposition performance test method"). This method requires a corresponding test device, which includes a housing, a main shaft, a support bearing, a test bearing and a loading bearing. One end of the main shaft passes through the housing to be connected to the power source, and the other end of the main shaft extends into the housing. The main shaft is supported in the housing by the support bearing and the test bearing. The loading bearing is located between the support bearing and the test bearing. The loading bearing is connected to an external radial loading mechanism to apply a radial load to the main shaft through the loading bearing. The test bearing is installed on the main shaft, and a heating element (such as a heater) surrounding the test bearing is installed on the housing. A spiral sealing structure is provided on the main shaft between the support bearing and the test bearing. The spiral sealing structure includes an inner sleeve and an outer sleeve. The inner sleeve is rotatably connected to the main shaft, and the outer sleeve is fixedly connected to the housing. The inner sleeve has an external thread and the outer sleeve has a There is an internal thread that engages with the external thread. The spiral sealing structure divides the housing into a support oil chamber and a test oil chamber through the cooperation of internal and external threads. The test bearing is located in the test oil chamber, and the support bearing and the loading bearing are both located in the support oil chamber. During the test, turbine oil is sprayed to three different bearings through different oil nozzles. The loading bearing and the support bearing located in the support oil chamber use the support turbine oil (hereinafter referred to as support oil), and the test bearing uses the turbine oil being tested (hereinafter referred to as test oil). The temperature of the support oil sprayed to the corresponding bearing is 71-82°C, and the temperature of the test oil sprayed to the test bearing is about 177°C. The spindle speed during the test is about 10,000 r / min. During the test, the temperature of the heating element is controlled at about 260°C. After several hours of testing, the physical and chemical properties, oil consumption, oil filtration and bearing deposition of the test oil are checked and analyzed to evaluate the high-temperature oxidation stability and anti-wear performance of the turbine oil.

[0232] However, through a large number of repetitive tests, it was found that the existing spiral sealing structure is difficult to effectively seal the test oil chamber and the support oil chamber under high-speed rotation conditions, resulting in the test oil in the test oil chamber continuously leaking into the support oil chamber. On the one hand, the leakage of the test oil into the support oil chamber will make the test of the test oil consumption inaccurate and affect the accuracy of the judgment of the test oil consumption; on the other hand, the turbine lubricating oil used for the test oil and the support oil is not the same. The viscosity and anti-wear performance of the support oil are higher than those of the test oil. After the test oil is mixed in, the viscosity and wear resistance of the support oil will be reduced, and the wear of the support bearing and the loading bearing will be accelerated.

[0233] Furthermore, the radial loading mechanism of the existing test device has flaws. Since the radial loading mechanism used in the standard method is a cylinder, the test requires the cylinder to use high-pressure compressed air to generate a vertical downward force on the loading bearing through the cylinder's piston rod (in the turbine oil deposition performance test, the cylinder needs to apply a force of approximately 2763N to the main shaft, and the cylinder's piston rod diameter is only about 10cm). This causes the loading bearing to generate a downward torque, thereby loading the test bearing. However, since the turbine oil deposition performance test is a durability test, the test time is long (the turbine oil test duration ranges from 100 to 200 hours each time). As the test progresses, the cylinder's sealing performance gradually fails due to aging of the sealing ring, and the test bearing loading pressure gradually decreases, seriously affecting the test accuracy. At the same time, since the cylinder loading system is subjected to high pressure and high load for a long time, and the temperature generated by the loading bearing as the main shaft rotates at high speed will be transferred to the cylinder, and the heating element is not far from the cylinder, the cylinder temperature is high during the test and circulating cooling water is needed to cool the cylinder loading system. However, as the test progresses over a long period of time, the cooling water seal in the cylinder loading system will gradually age and leak, seriously affecting the test operation and the service life of the test bench.

[0234] Therefore, a turbine lubricating oil deposition performance test device is provided in this embodiment to alleviate the problem in the prior art that the sealing structure of the test device is not tightly sealed, thereby affecting the test accuracy.

[0235] The embodiment is basically as shown in the attached Figure 7 and Figure 8 As shown, the turbine lubricating oil deposition performance test device includes a housing 201, a main shaft 202, a support bearing 203, a test bearing 204, a loading bearing 205, a sealing assembly 2060, a packing assembly 2070 and a radial loading mechanism 208. The main shaft 202 is rotatably connected to the housing 201 through the support bearing 203 and the test bearing 204. The loading bearing 205 is sleeved on the main shaft 202. The sealing assembly 2060 is located between the test bearing 204 and the loading bearing 205. The packing assembly 2070 and the loading bearing 205 are located on both sides of the support bearing 203. The radial loading mechanism 208 is used to apply a radial load to the loading bearing 205.

[0236] The main shaft 202 has an integrally formed shoulder 2021 at the end of the sealing assembly 2070 away from the support bearing 203 (that is, the left side of this embodiment), and no shoulders 2021 are set on both sides of the shoulder 2021 of the main shaft 202, thereby avoiding the problem of the main shaft 202 being easily broken due to the stress concentration position on the main shaft 202 being close to the bearing.

[0237] The inner wall of the box body 201 is cylindrical, and end covers 2011 are fixed at both ends of the box body 201. One of the end covers 2011 is provided with an air-avoidance hole for the main shaft 202 to pass through, and the other end cover 2011 closes the other end of the box body 201. At least two oil outlet holes 2012 are provided at the bottom of the box body 201. The end cover 2011 without air-avoidance holes, the sealing assembly 2060 and the sealing assembly 2070 divide the box body 201 into a supporting oil chamber and a test oil chamber. In this embodiment, the supporting oil chamber is located on the left side of the box body 201, and the test oil chamber is located on the right side of the box body 201. The box body 201 has three oil outlet holes 2012 at the bottom of one side of the supporting oil chamber, and two oil outlet holes 2012 at the bottom of one side of the test oil chamber. It also includes two recovery containers 206 for recovering lubricating oil. The two recovery containers 206 are used to recover the lubricating oil of the supporting oil chamber and the lubricating oil of the test oil chamber, respectively.

[0238] The sealing assembly 2060 includes at least two baffles 2061 installed on the box body 201 and at least two baffles 2062 fixed on the main shaft 202. The baffles 1 2061 and the baffles 2 2062 are alternately arranged along the axial direction of the main shaft 202. There is a continuous overlapping area in the projection of the baffles 1 2061 and the baffles 2 2062 on the cross section of the main shaft 202. There is a gap of 3-5 mm between the baffles 1 2061 and the adjacent baffles 2 2062 in the axial direction of the main shaft 202; there is a gap of 3-5 mm between the baffles 1 2061 and the outer surface of the main shaft 202, and there is a gap of 3-5 mm between the baffles 2 2062 and the inner wall of the box body 201. In this embodiment, baffle 1 2061 is in a ring shape, and baffle 2 2062 is in a disc shape; the number of baffle 1 2061 is one more than the number of baffle 2 2062, and there is baffle 1 2061 on both sides of baffle 2 2062. In this embodiment, the number of baffle 1 2061 is 5, and the number of baffle 2 2062 is 4.

[0239] An oil drain hole 2013 is also machined at the bottom of the box body 201. The oil drain hole 2013 is located between adjacent baffles 2061. The oil drain hole 2013 located at the left half of the sealing component 2060 is connected to the recovery container 206 for collecting support oil, and the oil drain hole 2013 located at the right half of the sealing component 2060 is connected to the recovery container 206 for collecting test oil.

[0240] To facilitate the installation of the bearings, bearing seats are set between the support bearing 203 and the box body 201, and between the test bearing 204 and the box body 201. The bearing seat and the baffle 2061 are both installed on the same continuous surface of the inner wall of the box body 201, so that the box body 201 can be used as an integral box body 201, and the installation surfaces of the box body 201 are all the same inner surface, which facilitates the molding of the box body 201 while reducing the difficulty of controlling the processing accuracy of the inner surface of the box body 201, and facilitates high-precision processing of the installation surface. A plurality of separation sleeves are mounted on the installation surface of the box body 201. The separation sleeves are used to fill the gaps between the parts on the installation surface, such as filling the gaps between adjacent baffles 2061, and filling the gaps between the baffle 2061 and the bearing seat.

[0241] The radial loading mechanism 208 includes a loading rod 2081, a pressure rod 2082, a pressure sensor 2083 and a weight 2084. The loading rod 2081 is located outside the box body 201, and the pressure rod 2082 is vertically slidably connected to the box body 201. The bottom of the pressure rod 2082 is pressed against the outer ring of the loading bearing 205. The loading rod 2081 is pressed on the top of the pressure rod 2082. The right end of the loading rod 2081 is rotatably connected to the box body 201 through a ball hinge. The left end of the loading rod 2081 (that is, the free end) can apply external force. In this embodiment, the external force is applied by hanging the weight 2084, and the pressure sensor 2083 is installed on the top of the pressure rod 2082.

[0242] In addition, in order to ensure that the test device can perform the deposition performance test of the lubricating oil, a heating element 207 is installed in the bearing seat where the test bearing 204 is installed.

[0243] The loading bearing 205 , the support bearing 203 and the test bearing 204 are all mounted on the same continuous outer surface of the main shaft 202 directly or indirectly through a fixed seat.

[0244] The free end of the main shaft 202 is threadedly connected with a locking nut 2010, and the locking nut 2010 and the shaft shoulder 2021 are located at both ends of the box body 201. A plurality of fixing sleeves are sleeved on the main shaft 202, and the plurality of fixing sleeves are used to fill the gap left after the main shaft 202 is installed between the shaft shoulder 2021 and the locking nut 2010 after the support bearing 203, the loading bearing 205, the test bearing 204 and the baffle 2062 are installed.

[0245] A gasket 2020 is provided between the locking nut 2010 and the test bearing 204. The gasket 2020 is sleeved on the main shaft 202. Two waist-shaped holes are provided on the end face of the locking nut 2010. Screws are passed through the waist-shaped holes to form an axial fixed connection between the locking nut 2010 and the gasket 2020 to ensure that the locking nut 2010 will not be loosened when the main shaft 202 is driven to reverse by the power source.

[0246] The sealing assembly 2070 has the same structure as the sealing assembly 2060. The sealing assembly 2070 includes at least two baffles 3 2071 installed in the box body 201 and at least two baffles 4 2072 fixed on the main shaft 202. The baffles 3 2071 and the baffles 4 2072 are alternately arranged along the axial direction of the main shaft 202. In this embodiment, there are two baffles 3 2071 and two baffles 4 2072.

[0247] An oil return hole 2014 is opened at the bottom of the box body 201 corresponding to each baffle plate 2072, and the oil return hole 2014 is connected to the recovery container 206 for collecting the support oil.

[0248] Three oil spray nozzles 2030 are also installed on the box body 201 , and the three oil spray nozzles 2030 are respectively facing the support bearing 203 , the loading bearing 205 and the test bearing 204 .

[0249] The specific implementation process is as follows:

[0250] The test apparatus of this embodiment is used to conduct a test in accordance with the FED-STD-791E Method 3410 standard method or an equivalent alternative method. During the test, the oil nozzle 2030 sprays corresponding lubricating oil onto the corresponding support bearing 203, loading bearing 205 and test bearing 204 respectively. By hanging a weight 2084 on the loading rod 2081 of the radial recording mechanism 80, the loading bearing 205 generates a radial load on the main shaft 202. The support oil and test oil generated during the test are recovered into the corresponding recovery container 206 through the oil outlet 2012, the oil drain hole 2013 and the oil return hole 2014 to facilitate the recycling of the corresponding lubricating oil.

[0251] During the test, first, because the baffle 2062 of the sealing component 2060 is fixed on the main shaft 202 and rotates at high speed synchronously with the main shaft 202, the high-speed rotation of the baffle 2062 in the closed box 201 will bring strong wind pressure. The existence of wind pressure will block the mist or droplet of lubricating oil (mist lubricating oil is hereinafter referred to as oil mist, and droplet of lubricating oil is hereinafter referred to as oil droplets) from approaching the sealing component 2060, forming a first-level barrier to the lubricating oil on both sides of the sealing component 2060; and the baffles 1 2061 and baffle 2 2062, which are alternately arranged in the sealing component 2060 and have a continuous overlapping area in the cross section of the main shaft 202, form layers of obstructions to the two chambers of the box 201, forming a second-level barrier, so that even if the oil mist or oil droplets pass through the first-level barrier, the migration speed will be greatly reduced under the second-level barrier, further reducing the oil The probability of mist or oil droplets migrating to the chamber on the other side; in addition, the baffle located in the middle area of the sealing component 2060 is at a lower temperature because it is far away from the supporting oil chamber and the test oil chamber. When the oil mist touches the baffle with a lower temperature after deceleration, it is more likely to form oil droplets and fall, further hindering the migration of the oil mist (which can be regarded as a three-level barrier); it can be seen that the sealing component 2060 of this embodiment forms multiple obstacles to oil mist or oil droplets with a simple structure, making the sealing performance of this embodiment very excellent; and even under multiple obstacles, oil mist still forms oil droplets and enters between the adjacent baffles 2061, then the entered lubricating oil will also fall to the bottom of the box body 201 under the action of gravity and be discharged in time along the oil drain hole 2013 set between the adjacent baffles 2061, thereby completely avoiding the situation where the lubricating oil on one side of the box body 201 is mixed with the lubricating oil on the other side.

[0252] In addition, in this embodiment, baffle 1 2061 and baffle 2 2062 are arranged alternately, and there is an axial gap of 3-5mm between baffle 1 2061 and baffle 2 2062, there is only a radial gap of 3-5mm between baffle 1 2061 and the main shaft 202, and there is only a radial gap of 3-5mm between baffle 2 2062 and the box body 201, which ensures that even if the main shaft 202 bends due to the radial load, it will not affect the sealing performance of the sealing component 2060 at all; the different temperatures of the two chambers in the box body 201 make the deformation of the structures on both sides of the sealing component 2060 different due to thermal expansion and contraction, and the existence of the gap will not affect the sealing performance of the sealing component 2060 at all, which ensures that the device has excellent sealing performance and the service life of the sealing component 2060 will not be reduced due to the increase in test time.

[0253] When loading the radial load, it is only necessary to adjust the weight of the weight 2084 suspended at the free end of the loading rod 2081 to adjust the size of the radial load applied to the loading bearing 205. Compared with the situation where the cylinder adjusts the radial load through high-pressure compressed gas, the adjustment of the radial load in this embodiment is simpler and more convenient, and the radial loading mechanism 208 of this embodiment will not have the problems of loading load fluctuation, easy aging of parts, and water seepage of the loading mechanism.

[0254] In addition, the setting of the sealing assembly 2070 of this embodiment ensures the sealing effect of the supporting oil chamber while also avoiding the problem of easy wear of the sealing ring caused by the use of the end cover 2011 and the sealing ring in the prior art to seal the part where the main shaft 202 passes through the box body 201.

[0255] In short, the sealing structure, radial loading method and structure of the main shaft 202 of this device have been greatly improved over the existing technology, so that the accuracy of the fuel consumption test of aviation lubricating oil under the lubricating oil deposition performance test can be guaranteed, and the migration of lubricating oil can be greatly reduced or even avoided, and the problem of wear of the support bearing 203 and the loading bearing 205 caused by oil leakage can be reduced or even avoided. In addition, the sealing component 2060 itself will not be scratched during long-term testing, the loading method of the radial loading mechanism 208 is simpler, more convenient and more secure, and the strength of the main shaft 202 and the box body 201 can also be easily achieved, which greatly extends the service life of the entire test device.

[0256] Example 5

[0257] The high-speed gear load capacity test described in Example 1 has many problems with the existing high-speed gear load capacity test method, specifically:

[0258] Turbine oil provides lubrication, cooling, and impurity transport for aircraft engine bearings, gears, etc. To ensure the aircraft engine's ability to operate safely, stably, and for a long time under high temperature and high speed conditions, the load-bearing capacity of turbine oil is particularly critical. The load-bearing capacity test of turbine oil is also a necessary inspection before the turbine oil undergoes airworthiness certification and is put into civil aviation use. To evaluate the load-bearing capacity of turbine oil, the turbine oil needs to be tested under operating conditions that simulate the actual aircraft engine.

[0259] In the prior art, the Ryder gear load capacity test method is used to test the load-bearing capacity of turbine lubricants under high-speed and high-load conditions. However, since the Ryder gear load capacity test method (hereinafter referred to as the Ryder test method) is a single-source method from abroad, and the Ryder gear testing machine used for this test method is also unique to abroad, domestic turbine lubricant manufacturers must send their turbine lubricants to foreign laboratories for testing if they want to conduct load-bearing capacity tests on turbine lubricants. However, cross-border testing requires extremely high financial and time costs, which limits the production of domestic turbine lubricants.

[0260] To solve the above problems, the inventors tried other ways to test the load-bearing capacity of turbine lubricating oil, such as improving the existing standard FZG gear testing machine in terms of power and turbine lubricating oil usage to obtain a high-speed FZG gear testing machine capable of performing high-speed gear testing (such as the high-speed gear load-bearing capacity testing machine disclosed in the enterprise standard number Q / 510107C.SD4001-2021, hereinafter referred to as the "high-speed FZG gear testing machine"). The reason for choosing the high-speed FZG gear testing machine for the test is that the tooth ratio of the test gear on the high-speed FZG gear testing machine is 3:2, while the tooth ratio of the Ryder gear testing machine is 1:1, but the actual gear tooth ratio in the domestic aircraft engine gearbox is more consistent with the tooth ratio on the high-speed FZG gear testing machine. Therefore, from this point of view, the use of the high-speed FZG gear testing machine can better and more accurately restore the actual operating conditions of the domestic aircraft engine.

[0261] During the test, the test was conducted on a high-speed FZG gear tester according to the operating conditions of a Ryder gear tester. The original standard FZG gear tester was used to test the load-bearing capacity of turbine lubricating oil under low-speed gears. When testing under low-speed gears, the standard FZG gear tester can choose two different gear pairs: one is the standard FZG-A gear pair, and the other is the standard FZG-C gear pair. During the test, the tester selects one of the gear pairs according to the different testing requirements of the turbine lubricating oil. During the test, the gear pair speed is approximately 1450r / min, the test time for each load level is constant speed operation for 15 minutes, the oil bath is 1.25L, the turbine lubricating oil temperature is ambient temperature under load level 5, and the oil temperature is controlled at 90°C for load level 5 and above. Under this test method, the load-bearing capacity test level of the turbine lubricating oil is 1-12.

[0262] When using the high-speed FZG gear tester for high-speed gear and high-load testing, whether using the standard FZG-A gear pair or the standard FZG-C gear pair, the test is carried out according to the operating conditions of the Ryder gear tester, that is, the pinion speed of the gear pair reaches 10,000 rpm, the test duration of each load level is constant speed operation for 10 minutes, the oil temperature of the turbine oil sprayed onto the gear under test is 74°C, and the lubrication flow rate is 1L / min. However, when using a standard FZG-A gear pair to meet the requirements of SAE AS5780 for testing aircraft turbine engine turbine lubricants, the gear failed at level 4 (corresponding to a loading load of 70 Nm), with a bonding temperature of 270°C at the time of failure. Because the failure level is too low (the theoretical loading load level for turbine lubricant load capacity testing can reach 16 levels), it is impossible to accurately distinguish the load-bearing capacities of different aircraft turbine engine turbine lubricants. When using a standard FZG-C gear pair to meet the requirements of SAE AS5780 for testing aircraft turbine engine turbine lubricants, the gear failed at level 7 (corresponding to a loading load of 123 Nm), with a bonding temperature of 275°C at the time of failure. In both cases, when the gear fails, the tooth surface wear of the pinion will suddenly increase to over 80% (for example, the wear at the previous level load test is around 10%, while the wear at the next level gear is over 80%). The test machine will vibrate significantly, the turbine lubricant will overheat, and the oil film will rupture and lose its lubricating properties. When using the standard FZG-A gear pair to test helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734, the test load reached level 7, the bonding temperature at which the gears failed was 395°C, the tooth surface wear of the pinion suddenly increased to over 80%, the testing machine vibrated significantly, the helicopter gearbox lubricant overheated, the oil film ruptured and lost its lubricating properties; when using the standard FZG-C gear pair to test helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734, the pinion did not fail until the maximum load (level 16 load, corresponding to a loading load of 280Nm), and it was impossible to distinguish the load-bearing capacity of this type of lubricant.

[0263] It can be seen that the high-speed FZG gear testing machine cannot be used to evaluate the load-bearing capacity of turbine lubricating oil under high-speed and high-load conditions, regardless of whether it uses the standard FZG-A gear pair or the standard FZG-C gear pair. As a result, there is still no other method for testing the load-bearing capacity of turbine lubricating oil under high-speed gear and high load conditions except the Ryder gear load-bearing capacity test method.

[0264] Therefore, this embodiment proposes a method for testing the load-bearing capacity of turbine lubricating oil high-speed gears to solve the problem in the prior art of lacking other methods for testing the load-bearing capacity of turbine lubricating oil under high-speed gears except the Ryder gear load-bearing capacity test method.

[0265] The embodiment is basically as shown in the attached Figures 9 to 18As shown, the test method for the load-bearing capacity of turbine lubricating oil high-speed gears includes using a high-speed FZG gear testing machine for testing. The testing machine uses FZG-AR gear pairs and FZG-CR gear pairs. Both gear pairs include a large gear and a small gear. The gear ratio of the large gear and the small gear is 3:2. The center distance of the FZG-AR gear pair and the FZG-CR gear pair is the same, both of which are 91.5mm. In this embodiment, the number of teeth of the large gear is 24, the number of teeth of the small gear is 16, and the module is 4.5; the gear pressure angle of the FZG-AR gear pair is 20°, and the gear pressure angle of the FZG-CR gear pair is 20°; the gear surface hardness of the FZG-AR gear pair is 58-63HRC, the core hardness is 33-41HRC, the tooth surface carburized layer depth is 0.9-1.3mm, and the tooth root carburized layer depth is 0.75-1.15mm; the FZG-CR gear pair The gear surface hardness is 58-63 HRC, the core hardness is 30-42 HRC, and the tooth surface and tooth root carburized layer depths are both 1.0-1.2 mm. The sum of the modification coefficients for the FZG-AR and FZG-CR gear pairs is 0.34-0.36. The modification coefficients for the small gears in the FZG-AR gear pair range from 0.45-0.58, while the modification coefficients for the small gears in the FZG-CR gear pair range from 0.15-0.27. The gears in both the FZG-AR and FZG-CR gear pairs are made of AISI 9310 aviation-grade material. The basic parameters of the FZG-AR and FZG-CR gear pairs in this embodiment are shown in Table 7 below.

[0266] Table 7 Basic parameters of FZG-AR gear pair and FZG-CR gear pair

[0267]

[0268]

[0269] When the FZG-AR gear pair and the FZG-CR gear pair are used in conjunction with a high-speed FZG gear testing machine for testing, the pinion speed reaches 10,000±10 r / min, the test turbine oil inlet temperature is 74±2.5°C, the test turbine oil flow rate is 1,000±5 mL / min, and the test time is 10 min±10 s. The FZG-AR gear pair is used to test helicopter gearbox lubricating oil that meets the requirements of MIL-PRF-85734, and the FZG-CR gear pair is used to test turbine oil that meets the requirements of SAE AS5780. During the test, a pinion tooth surface wear area ratio of 17%-20% is used as the basis for determining gear failure. In this embodiment, a pinion tooth surface wear area of 18% can be selected as the basis for determining gear failure.

[0270] To verify this embodiment, three gear sets were set for the FZG-AR gear pair and the FZG-CR gear pair in Table 1 above. Three pairs of gear sets with the same parameters were produced. The sum of the modification coefficients of each pair of gears was 0.3532. The modification coefficients of all gear sets are shown in Table 8. The correspondence between the load level, loading load and Ryder test method using this method is shown in Table 9 below (this correspondence has been disclosed in the existing standard).

[0271] Table 8 Parameters of FZG-AR and FZG-CR gear pairs under different modification coefficients

[0272]

[0273] Table 9 Correspondence between load level and loading load

[0274] Load level The load in this embodiment is N·m Ryder test method load, kPa 1 18.0 34.0 2 35.0 68.0 3 53.0 102.0 4 70.0 136.0 5 88.0 170.0 6 105.0 204.0 7 123.0 238.0 8 140.0 272.0 9 158.0 306.0 10 175.0 340.0 11 193.0 374.0 12 210.0 408.0 13 228.0 442.0 14 245.0 476.0 15 263.0 510.0 16 280.0 544.0

[0275] A total of 18 gear pairs were tested in the three test groups mentioned above. A total of 9 gear pairs in test groups 1, 2, and 3 were tested using helicopter gearbox lubricant that meets the requirements of MIL-PRF-85734 (AeroShell Turbine Oil 555, a helicopter gearbox lubricant currently used in over 70% of the global civil aviation market, was selected as the test reference oil). The test results are shown in Table 10 below:

[0276] Table 10 Test data of FZG-AR gear pair

[0277]

[0278]

[0279]

[0280] Turbine lubricants meeting SAE AS5780 requirements (e.g., Mobil Jet Oil II, a turbine lubricant currently used in over 55% of the global civil aviation market, was selected as the test reference oil) were used to test a total of nine gear pairs in test groups 4, 5, and 6. The test results are shown in Table 11 below.

[0281] Table 11 Test data of FZG-CR gear pair

[0282]

[0283]

[0284]

[0285] According to the data in Table 10 above, when the gear pair of Test Group 1 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester using helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734, the load level at which the gears failed could reach level 9 or even level 10. This ensures that when the helicopter gearbox lubricants are tested under this gear pair, they can be tested to a load level of at least level 8 without completely damaging the FZG tester.

[0286] When the gear pair in Test Group 2 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester using helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734, the load level at which the gears failed was able to reach level 10 or even level 12. This ensures that when testing helicopter gearbox lubricants using this gear pair, they can be tested to a load level of at least level 9 without completely damaging the FZG tester.

[0287] When the gear pair of Test Group 3 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester using helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734, the load level at which the gears failed was able to reach levels 11-12. This ensures that when the helicopter gearbox lubricant is tested under this gear pair, it can be tested to a load level of at least 10 without completely damaging the FZG tester.

[0288] Therefore, from the test data set in Table 10 above, it can be seen that when the FZG-AR gear pair of this embodiment is tested on a helicopter gearbox lubricant that meets the requirements of MIL-PRF-85734 on a high-speed FZG gear tester according to the operating conditions of a Ryder gear tester, the tooth surface failure load level can reach 9-12 (level 9 corresponds to a load of 158Nm, and level 12 corresponds to a load of 210Nm). Figures 5 to 7 It can be seen that the tooth surface wear area of the FZG-AR gear pair for helicopter gearbox lubricants that meet the requirements of MIL-PRF-85734 shows a basically linear increase during the test. It can also be found that the load-bearing capacity of the helicopter gearbox lubricant when the total wear area of the 16 tooth surfaces of the pinion accounts for 18% of the total effective contact area (that is, the load-bearing capacity of the helicopter gearbox lubricant under the basis of gear failure judgment) can be found. Unlike the standard FZG-A gear pair, there is no need to stop the test until large-area bonding occurs on the gear surface, resulting in instantaneous high temperature. This greatly reduces the impact on the life of the high-speed FZG gear testing machine.

[0289] As for the FZG-CR gear pair, the data in Table 4 show that when the gear pair in Test Group 4 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester, the load level at which the gear failed could reach level 9 or even level 10. This ensures that when a turbine lubricant meeting SAE AS5780 requirements is tested on the gear pair in Test Group 4, the load level can be tested to at least level 8 without completely damaging the high-speed FZG tester.

[0290] When the gear pair in Test Group 5 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester, the load level at which the gear failed was able to reach level 11. This ensures that when a turbine lubricant meeting SAE AS5780 requirements is tested on the gear pair in Test Group 5, it can be tested to a load level of at least level 10 without completely damaging the high-speed FZG tester.

[0291] When the gear pair in Test Group 6 was tested on a high-speed FZG gear tester under the operating conditions of a Ryder gear tester, the load level at which the gear failed was able to reach levels 12-13. This ensures that when a turbine lubricant meeting SAE AS5780 requirements is tested on the gear pair in Test Group 6, it can be tested to a load level of at least 11 without completely damaging the high-speed FZG tester.

[0292] From the above analysis, it can be seen that when the turbine lubricating oil that meets the requirements of SAE AS5780 is tested on a high-speed FZG gear tester according to the operating conditions of the Ryder gear tester, the bonding temperature of the gear is greatly increased, and nearly 90% of the test data can achieve the 9th level turbine lubricating oil load capacity test under the premise of ensuring that the high-speed FZG tester is completely undamaged. At the same time, the gear wear area basically increases linearly under different load levels (combined with Figures 14 to 16 ), it is also possible to find the load-bearing capacity of the turbine lubricant when the total wear area of the 16 tooth surfaces of the pinion accounts for 18% of the total effective contact area (that is, the load-bearing capacity of the turbine lubricant under the basis of gear failure judgment). During the test, there is no need to stop the test only when large-scale bonding and instantaneous high temperature occur on the tooth surfaces, so as to avoid damage to the high-speed FZG gear testing machine. In addition, it can also make the range of the tooth surface wear area before the gear failure more stable, which is conducive to improving the reliability of the test.

[0293] From the above explanation, combined with the test data, it can be seen that this solution, through improvements to the standard FZG-A and FZG-C gear pairs and the use of a high-speed FZG gear testing machine, can ensure that the load level of turbine lubricants required by SAE AS5780 and MIL-PRF-85734 at the maximum effective bonding temperature is not less than level 9. This level of test load level can basically meet the testing requirements of existing domestic turbine lubricants. Therefore, this solution breaks the situation where the Ryder gear load capacity test method is the only method used to test the load capacity of turbine lubricants, greatly reducing the cost of turbine lubricant load capacity testing. In addition, as shown in Tables 10 and 11 above, the maximum failure load of the three parallel tests of the same test group of gear pairs does not differ by more than 1 level, indicating high test repeatability, which also demonstrates the high reliability of the testing method.

[0294] The above is only an embodiment of the present invention. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the field are aware of all common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the field can improve and implement this scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for determining the airworthiness conformity of aviation turbine engine lubricating oil, characterized by: Includes the following: CTSOA certification: The turbine lubricant is certified according to the standards. If it passes the certification, it will obtain CTSOA and undergo engine STC certification. If it fails the certification, the turbine lubricant is deemed unairworthy. Engine STC certification: Turbine lubricating oil is tested on an engine test bench for no less than a preset number of C cycles. If the test passes, the oil is awarded STC and can be used on routes. If the test fails, the oil is deemed unairworthy. Route application: Apply the turbine lubricant to the designated route for a period of not less than the preset flight time, and monitor the application. If the application passes the monitoring, the turbine lubricant is deemed airworthy. If the monitoring application fails, the turbine oil is deemed unairworthy; The CTSOA certification includes: certification of turbine oil performance; The performance review includes: type inspection and quality control inspection; Type inspection, including: deposition performance test; The deposition performance test includes: a high-temperature bearing deposition performance test, which adopts an aviation lubricating oil deposition performance test device, including: a housing, a main shaft, a support bearing, a test bearing, a loading bearing and a sealing assembly. The sealing assembly is located between the test bearing and the loading bearing. A heating element is installed in the bearing seat where the test bearing is installed. At least two oil outlets are provided at the bottom of the housing, and the oil outlets are located on both sides of the sealing assembly. The main shaft is rotatably connected in the housing through the support bearing and the test bearing. The loading bearing is sleeved on the main shaft. The sealing assembly includes at least two baffles 1 installed on the housing and at least two baffles 2 fixed on the main shaft. Baffles 1 and baffles 2 are alternately arranged along the axial direction of the main shaft. There is a continuous overlapping area in the projection of baffles 1 and baffles 2 on the cross section of the main shaft. There is a gap of 3-5mm between baffle 1 and the adjacent baffle 2 in the axial direction of the main shaft.

2. The method for determining the airworthiness compliance of an aviation turbine engine lubricant according to claim 1, wherein: The CTSOA certification also includes: reviewing the chemical composition of the turbine lubricant according to the requirements of CTSO-2C704 standard; if the certification is passed, a CTSOA is obtained and the engine STC certification is carried out; if the certification is not passed, the turbine lubricant is determined to be unairworthy; The chemical composition review includes determining whether the components in the turbine lubricating oil meet the preset chemical composition requirements.

3. The method for determining the airworthiness compliance of an aviation turbine engine lubricant according to claim 2, wherein: The type inspection also includes: conducting physical property tests, chemical property tests, stability performance tests, friction performance tests and additional tests on the turbine lubricating oil, and judging whether the turbine lubricating oil meets the type inspection requirements based on the test results. If so, a quality control inspection is conducted; if not, the turbine lubricating oil is judged to be unairworthy. The quality control inspection includes: when batches of turbine lubricants that have passed type inspection are produced, quality control inspection is carried out on no less than preset batches of turbine lubricants to determine whether the turbine lubricants meet the quality control inspection requirements. If so, the turbine lubricants are certified to obtain CTSOA and undergo engine STC certification; if not, the turbine lubricants are determined to be unairworthy. The quality control inspection includes tests for kinematic viscosity, pour point, open-cell flash point, foam characteristics, total acid number, sediment / ash content, trace metal content, oxidation corrosion stability, thermal stability corrosion, dynamic coking, and gas phase coking.

4. The method for determining the airworthiness compliance of an aviation turbine engine lubricant according to claim 1, wherein: The engine STC certification includes: Drain and clean the engine stand for maintenance; Replace the turbine oil on the engine test bench; Conduct engine C cycle test; the number of cycles shall not be less than the preset C cycle number; During the engine C cycle test, engine operation data collection and analysis, turbine oil consumption monitoring and sampling analysis are performed; After the engine C cycle test, perform oil sampling analysis, visual inspection and disassembly inspection; Based on the engine operation data collection and analysis results, sampling analysis results, visual inspection results and disassembly inspection results, determine whether each result meets the preset engine STC certification requirements. If so, obtain the STC and implement route application; if not, determine that the turbine lubricant oil is not airworthy.

5. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 4, characterized in that: The preset engine STC certification requirements include: The change trends of various parameters of the engine equipped with the test turbo lubricant over the cycle number are consistent with those of the reference turbo lubricant, with no obvious mutations; the reference turbo lubricant is a commercial turbo lubricant; During the engine C cycle test, the test engine did not exhibit any adverse operating conditions such as parameter exceeding limits, surge, slow acceleration, and / or speed hanging caused by the turbine lubricant. During the engine STC certification, no adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were found, and no engine component debris exceeding preset limits was found in the oil filter or magnetic plug. After the engine C cycle test, the visual inspection results of the test engine's TGB, AGB, IGB and lubricating oil system were normal, and there was no oil leakage related to the replacement of turbine lubricating oil in the test engine and related components of the lubricating oil system.

6. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 1, characterized in that: The preset C cycle number is at least 2000 times.

7. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 1, characterized in that: The route application includes: applying the turbine lubricating oil to a designated aircraft model and a designated route, and conducting a route application comparison test; A single test includes: replacing the test turbine oil and reference turbine oil in the engines on both sides of the test aircraft respectively, and conducting two flight segments of testing, and the flight time of the two segments is not less than the first preset flight time and the second preset flight time respectively. The two segments are a short-range route with short takeoffs and landings and a long-range route with long takeoffs and landings; Collect and record the operating data of the aircraft and engine in each flight segment during the test flight; Sampling and analysis of turbine oil in engines, starters and IDGs on both sides; Conduct visual and disassembly inspections of the engine oil filter and metal chip sensor; Based on the comparative analysis of the flight test data collected and recorded for each flight segment, visual inspection results, test oil sampling and analysis, and disassembly inspection results, determine whether the test is qualified. If so, proceed to the next test; if not, determine that the turbine oil is not airworthy. After the visual inspection and sampling analysis are completed, the test engine will be replaced with the original commercial turbine oil as needed, and the engine oil system, starter and IDG will be cleaned and maintained to restore the engine to an airworthy state; The number of tests is determined based on the total flight time of the test being no less than the preset flight time, and it is judged whether each test meets the preset route application qualification requirements. If so, the turbine lubricant is determined to be airworthy; if not, the turbine lubricant is determined to be unairworthy.

8. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 7, characterized in that: The pre-set route application eligibility requirements include: During the flight test, the engine did not experience any adverse operating conditions such as exceeding operating parameters, surging, slow acceleration, and / or speed hanging caused by the turbine lubricant. No adverse operating characteristics affecting safety or damage exceeding preset limits related to the turbine lubricant were found during the entire line test. No engine component debris exceeding preset limits was found in the oil filter or magnetic plug. After the test flight, the visual inspection results of the engine's TGB, AGB, IGB and lubricating oil system were normal, and no oil leakage related to the replaced test turbine lubricating oil was found in the engine and lubricating oil system related components; The performance change trend of the tested turbine lubricating oil during the test flight meets the preset aircraft maintenance requirements.

9. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 7, characterized in that: The preset flight time is at least 2000 hours.

10. The method for determining the airworthiness compliance of aviation turbine engine lubricating oil according to claim 1, characterized in that: Also includes: Promotion steps: Promote turbine lubricants that are judged to be airworthy and supervise the promotion process.

Images