Fault monitoring method for air lubricating oil radiator of aero-engine

Abstract

The invention belongs to the field of gas turbine engines, and particularly relates to an aero-engine air lubricating oil radiator fault monitoring method. The method comprises the following steps: carrying out a lubricating oil side flow resistance characteristic test on a newly processed air lubricating oil radiator, calculating a lubricating oil side pressure difference P and a lubricating oil temperature rise correction coefficient theta according to a test record table, and correcting the lubricating oil side pressure difference P to obtain theoretical correction of the lubricating oil side corrected pressure difference P; then, a lubricating oil side flow resistance characteristic test is conducted on an air lubricating oil radiator product in actual work, a proportionality coefficient parameter upper limit k upper limit and a proportionality coefficient parameter lower limit k lower limit are calculated, and a flow resistance proportionality coefficient k after calculation and correction is corrected through a lubricating oil side correction pressure difference P theory; and performing anomaly judgment according to the relationship between the flow resistance proportionality coefficient k and the upper limit of the proportionality coefficient parameter upper limit k and the lower limit of the proportionality coefficient parameter lower limit k. An opening cover does not need to be arranged on an engine case, and the weight of an engine is reduced. Workers do not need to stop for inspection, and the inspection efficiency of the workers is improved.

Description

Technical Field

[0001] The present application belongs to the field of gas turbine engines, and in particular to a method for monitoring faults of an aircraft engine air-oil radiator. Background Art

[0002] With the continuous development of aviation engine technology, the heat dissipation demand of the engine's lubricating oil system and high-power components has increased. It is necessary to use the low-temperature outer duct air through the air-lubricating oil radiator to cool a stream of high-temperature lubricating oil. The cooled low-temperature lubricating oil flows to the cooled engine accessories and aircraft accessories to cool the high-temperature accessories. Since the heat exchange temperature difference between the cold and hot sides of the air-lubricating oil radiator is large, which is 2 to 3 times the temperature difference between the cold and hot sides of the engine fuel oil radiator, the thermal stress inside the air-lubricating oil radiator is greater and the mean time between failures is shorter. At the same time, the air-lubricating oil radiator is located in the outer duct of the engine. Due to the obstruction of the casing, daily inspections cannot effectively determine whether the air-lubricating oil radiator has leakage, blockage and other abnormal conditions.

[0003] The existing technical solution is to open a cover or other inspection port on the engine casing. Every time the engine is finished, the worker uses a borescope or visual inspection to check whether the air-lubricating oil radiator has leakage or other abnormal conditions. The disadvantages are: 1) It takes up the workers' maintenance time and needs to use human eyes to judge the fault, which is inefficient. 2) It is necessary to open a special cover, which increases the weight of the engine. 3) It can only check for leakage faults, and cannot effectively check for blockage faults inside the air-lubricating oil radiator. 4) It can only be checked after the engine is stopped, and real-time monitoring is not possible.

[0004] Therefore, how to more effectively monitor whether the air-lubricating oil radiator is abnormal is a problem that needs to be solved. Summary of the invention

[0005] The purpose of the present application is to provide a method for monitoring faults of an aircraft engine air-oil radiator, so as to solve the problem that existing technical means cannot effectively monitor in real time whether the air-oil radiator is abnormal.

[0006] The technical solution of the present application is: a method for monitoring faults of an aircraft engine air oil radiator, comprising:

[0007] Set up an air-lubricating oil radiator flow resistance characteristic test bench to carry out the oil side flow resistance characteristic test on the newly processed air-lubricating oil radiator. After the test is completed, all the flow resistance characteristic data collected during the test are recorded in the test record sheet;

[0008] According to the flow resistance characteristic data in the test record table, draw a curve chart of the lubricating oil side pressure difference △P of the air lubricating oil radiator changing with the lubricating oil temperature T and the lubricating oil volume flow rate qv, obtain the overall change trend of each state point of the change curve chart by interpolation, and judge whether there is a state point in the change curve chart where the lubricating oil side pressure difference result deviates from the overall trend; if so, remove the abnormal data;

[0009] The lubricating oil side pressure difference △P, lubricating oil temperature T and lubricating oil volume flow rate qv data in the change curve diagram after deleting abnormal data are obtained, and the relationship between the lubricating oil side pressure difference △P and the lubricating oil temperature T and the lubricating oil volume flow rate qv is fitted by a polynomial, and the fitting relationship is obtained as follows: △P(T,qv)=F(T,qv); the dynamic viscosity and temperature of the lubricating oil are obtained according to the lubricating oil type, the inlet lubricating oil temperature, the outlet lubricating oil temperature and the average inlet and outlet lubricating oil temperature of the radiator during the test are obtained according to the test record sheet, and the lubricating oil temperature rise correction coefficient θ is calculated. The lubricating oil side pressure difference △P is corrected according to the lubricating oil temperature rise correction coefficient θ to obtain the lubricating oil side corrected pressure difference △P 理论修正 ;

[0010] The oil side flow resistance characteristic test was carried out on the air-lubricating oil radiator products that had different flow resistance failures, and the product test data results were obtained and the upper limit k of the proportional coefficient parameter was calculated. 上限 and the lower limit k of the proportionality coefficient parameter 下限 , the flow resistance fault includes the flow resistance increase fault and the flow resistance decrease fault;

[0011] When the engine equipped with air-lubricating oil radiator is running normally, collect the normal operation data of the air-lubricating oil radiator and correct the pressure difference △P on the lubricating oil side. 理论修正 Calculate the corrected flow resistance proportional coefficient k and determine whether the corrected flow resistance proportional coefficient k is within the upper limit k of the proportional coefficient parameter 上限 and the lower limit k of the proportionality coefficient parameter 下限 If so, the k value is considered normal and the air-lubricating oil radiator is working normally.

[0012] Preferably, the lubricating oil side flow resistance characteristic test is specifically as follows:

[0013] Arrange temperature measuring points at the lubricating oil side inlet of the radiator, volume flow measuring points at the inlet of the radiator, and pressure measuring points at the inlet and outlet of the radiator;

[0014] The flow resistance characteristic test of the air-lubricating oil radiator carried out covers all the working conditions in the test record table; different working conditions in the test record table are tested separately, and for the test under each working condition, the inlet temperature data, inlet volume flow data, inlet and outlet pressure data of the radiator are recorded after the test data is stable for 3 minutes; the test requires that no fluid flows on the air side and only the lubricating oil side; considering the influence of heat leakage, the outer surface of the air-lubricating oil radiator is covered with insulation material.

[0015] Preferably, the test record table requires that the test conditions carried out by the air-lubricating oil radiator can cover M types of lubricating oil temperatures × N types of lubricating oil volume flow rates; the highest and lowest values ​​of the M types of lubricating oil temperatures selected in the test record table come from the highest and lowest temperatures that occur when the air-lubricating oil radiator is on the engine; the maximum value of the N types of lubricating oil volume flow rates selected in the test record table comes from the maximum value that may occur when the air-lubricating oil radiator is on the engine; the minimum value of the lubricating oil volume flow rate is obtained by multiplying the maximum value of the N types of lubricating oil volume flow rates by a correction coefficient, and the correction coefficient is between 0.1 and 0.4.

[0016] Preferably, the specific method for judging whether there is a state point in the change curve diagram whose lubricating oil side pressure difference result deviates from the overall trend is: obtaining the overall interpolation in the overall change trend, and judging each state point separately, when the difference between the interpolation of a state point and the overall interpolation is greater than the set threshold, if so, the state point is judged to be abnormal data.

[0017] Preferably, the fitting relationship is: △P 理论 (T,qv)=p00+p10*T+p01*qv+p20*T^2+p11*T*qv+p02*qv^2+p30*T^3+p21*T^2*qv+p12*T*qv^2.

[0018] Preferably, the lubricating oil side corrected pressure difference ΔP under the lubricating oil temperature rise condition is 理论修正 = lubricating oil side pressure difference △P×θ;

[0019] The calculation formula of the lubricating oil temperature rise correction coefficient θ is:

[0020]

[0021] Where θ is the correction factor for the temperature rise of the lubricating oil in the pressure difference, μ is the dynamic viscosity of the lubricating oil, ρ is the density of the lubricating oil, and T in is the lubricating oil temperature at the radiator inlet, T out is the outlet lubricating oil temperature of the radiator, T m is the average temperature of the lubricating oil at the inlet and outlet of the radiator, It represents the integration operation of the function from the inlet temperature to the outlet temperature, and the subscript T represents the physical property parameter when the temperature is T.

[0022] Preferably, the upper limit k of the proportionality coefficient parameter is 上限The specific acquisition method is as follows: collect air-lubricating oil radiator products with increased flow resistance caused by blockage, scaling, etc. in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet; divide the test data results of the product with abnormally increased flow resistance by the calculation results of the fitting relationship to obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation of the proportional coefficient; set the upper limit k of the proportional coefficient parameter 上限 As the reference upper limit of the proportionality coefficient between the abnormally increased flow resistance and the calculated flow resistance pressure difference, the upper limit of the proportionality coefficient parameter k 上限 is the mean value of the proportionality coefficient minus the standard deviation of the proportionality coefficient.

[0023] Preferably, the lower limit k of the proportionality coefficient parameter is 下限 The specific acquisition method is as follows: collect air-lubricating oil radiator products with flow resistance reduction failures such as cracks and leakage in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet; divide the test data results of the product with abnormally reduced flow resistance by the calculation results of the fitting relationship to obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation; the lower limit k of the proportional coefficient is 下限 As the reference lower limit of the proportionality coefficient between the abnormally reduced flow resistance and the calculated flow resistance pressure difference, the lower limit of the proportionality coefficient parameter k 下限 is the mean + standard deviation of the proportionality coefficient.

[0024] Preferably, the corrected flow resistance proportional coefficient k is specifically obtained by: arranging temperature and pressure measuring points at the inlet and outlet of the lubricating oil side of the air-lubricating oil radiator, arranging a lubricating oil volume flow measuring point at the inlet of the air-lubricating oil radiator, processing the monitoring data of the measuring points through the control system of the engine, and calculating the corrected pressure difference ΔP on the lubricating oil side according to the fitting relationship and the calculation formula of the lubricating oil temperature rise correction coefficient θ 理论修正 , the actual pressure difference △P on the lubricating oil side obtained through the radiator inlet and outlet pressure measuring points 真实 Corrected pressure difference with lubricating oil side △P 理论修正 Divide the actual flow resistance and the corrected flow resistance after theoretical calculation to obtain the proportional coefficient k, k = △P 真实 / △P 理论修正 .

[0025] Preferably, when the k value is abnormal for five consecutive operating points or for one consecutive hour, it is considered that the air-lubricating oil radiator is faulty and needs to be returned to the factory for repair.

[0026] The aircraft engine air oil radiator fault monitoring method of the present application has the following advantages:

[0027] 1. Use pressure, temperature and other sensors to obtain performance data and compare them with theoretical calculated values ​​to indirectly monitor whether the air-lubricating oil radiator has failed, avoiding the need to open a cover on the engine casing and reducing the weight of the engine. Workers do not need to stop the machine for inspection, which improves the efficiency of workers' inspection.

[0028] 2. Through performance data monitoring, real-time monitoring can be achieved. When the air-lubricating oil radiator fails, it can be repaired immediately to avoid more serious damage.

[0029] 3. In addition to discovering radiator oil leakage faults, testing through performance data can also detect faults such as blockage inside the radiator that cause increased flow resistance, which workers cannot detect by visually inspecting the product appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0031] Figure 1 This is a schematic diagram of the medium flow of the air-lubricating oil radiator of this application;

[0032] Figure 2 This is a schematic diagram of the overall process of this application;

[0033] Figure 3 This is a graph showing the change of radiator pressure difference with temperature and volume flow rate for this application;

[0034] Figure 4 This is a schematic diagram of the variation of kinematic viscosity of the lubricating oil with temperature in this application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1 The air-lubricating oil radiator is equipped with two media, air and lubricating oil, respectively. The air and lubricating oil exchange heat through the air-lubricating oil radiator. The air from the engine outer liner flows along the fins outside the air-lubricating oil radiator tube, and the high-temperature lubricating oil from the engine accessories or aircraft accessories flows in the air-lubricating oil radiator tube. Under the installed condition, the inlet and outlet temperature and flow rate of the lubricating oil side of the air-lubricating oil radiator are measured by sensors.

[0037] Specifically, it relates to a method for monitoring faults of an aircraft engine air lubricating oil radiator, such as Figure 2 , including the following steps:

[0038] Step S100, setting up an air-lubricating oil radiator flow resistance characteristic test bench to carry out a lubricating oil side flow resistance characteristic test on a newly processed air-lubricating oil radiator. After the test is completed, register all flow resistance characteristic data collected during the test in a test record sheet. The flow resistance characteristic data includes lubricating oil temperature, lubricating oil pressure, lubricating oil volume flow rate, etc. The obtained flow resistance characteristic data is used as a benchmark for fault detection.

[0039] The air-lubricating oil radiator flow resistance characteristic test bench can provide lubricating oil with different temperatures and flow rates for the air-lubricating oil radiator; the lubricating oil side flow resistance characteristic test is specifically as follows:

[0040] A temperature measuring point is arranged at the inlet of the lubricating oil side of the radiator, a volume flow measuring point is arranged at the inlet of the radiator, and a pressure measuring point is arranged at the inlet and outlet of the radiator.

[0041] The flow resistance characteristic test of the air-lubricating oil radiator covered all the working conditions in the test record table. The different working conditions in the test record table were tested separately. For each test under each working condition, the inlet temperature data, inlet volume flow data, and inlet and outlet pressure data of the radiator were recorded after the test data stabilized for 3 minutes. The test required that no fluid flowed through the air side and only the lubricating oil side flowed through the fluid. Considering the influence of heat leakage, the outer surface of the air-lubricating oil radiator was covered with insulation material.

[0042] The test record form requires that the test conditions carried out on the air-oil radiator should cover M types of oil temperatures × N types of oil volume flow rates.

[0043] The highest and lowest values ​​of the M types of lubricating oil temperatures selected in the test record table are the highest and lowest temperatures that may occur on the engine of the air lubricating oil radiator. The series of temperatures selected in the middle should be evenly distributed between the highest and lowest temperatures.

[0044] The maximum value of the N types of lubricating oil volume flow rates selected in the test record table should be the maximum value that may appear on the engine of the air lubricating oil radiator. The minimum value of the lubricating oil volume flow rate is obtained by multiplying the maximum value of the N types of lubricating oil volume flow rates by a correction factor. The recommended correction factor is between 0.1 and 0.4.

[0045] The test record table is shown in Table 1:

[0046] Table 1 Test record table (recording radiator pressure difference results)

[0047]

[0048] Step S200, as Figure 3According to the flow resistance characteristic data in the test record table, draw a curve of the lubricating oil side pressure difference △P of the air lubricating oil radiator with the lubricating oil temperature T and the lubricating oil volume flow qv, obtain the overall change trend of each state point of the change curve through interpolation, and judge whether there is a state point in the change curve whose lubricating oil side pressure difference result deviates from the overall trend. If so, the abnormal data should be eliminated.

[0049] The specific judgment method is to obtain the overall interpolation in the overall change trend, and judge each state point separately. When the difference between the interpolation of a state point and the overall interpolation is greater than the set threshold, if so, the state point is judged to be abnormal data.

[0050] Step S300, obtaining the lubricating oil side pressure difference △P, lubricating oil temperature T and lubricating oil volume flow qv data in the change curve diagram after deleting the abnormal data, and using a polynomial to fit the relationship between the lubricating oil side pressure difference △P and the lubricating oil temperature T and the lubricating oil volume flow qv to obtain a fitting relationship, which is: △

[0051] P(T,qv)=F(T,qv). The fitting relationship is preferably Formula (1), where pxx is a coefficient to be determined in the fitting formula.

[0052] △P 理论 (T,qv)=p00+p10*T+p01*qv+p20*T^2+p11*T*qv+

[0053] p02*qv^2+p30*T^3+p21*T^2*qv+p12*T*qv^2(1).

[0054] Step S400: When the air-lubricating oil radiator is assembled on the engine, the lubricating oil temperature at the radiator inlet will decrease due to the cooling effect of the air. Unlike air, fuel and other media, the physical properties of lubricating oil will change dramatically in the low temperature zone. Figure 3 Therefore, the average inlet and outlet parameters of the air-lubricating oil radiator cannot be used to reflect the overall situation, and corrections need to be made to the theoretical calculation results that do not consider the lubricating oil temperature rise.

[0055] According to the type of lubricating oil, the dynamic viscosity and temperature of the lubricating oil are obtained. According to the test record table, the inlet lubricating oil temperature, outlet lubricating oil temperature and the average inlet and outlet lubricating oil temperature of the radiator during the test are obtained. The lubricating oil temperature rise correction coefficient θ is calculated. According to the lubricating oil temperature rise correction coefficient θ, the lubricating oil side pressure difference △P is corrected to obtain the lubricating oil side corrected pressure difference △P 理论修正 Corrected oil side pressure difference △P considering oil temperature rise 理论修正 =Lubricating oil side pressure difference △P×θ.

[0056] like Figure 4The lubricating oil temperature rise correction coefficient θ is calculated by integration. The calculation formula of the lubricating oil temperature rise correction coefficient θ is:

[0057]

[0058] Where θ is the correction factor for the temperature rise of the lubricating oil in the pressure difference, μ is the dynamic viscosity of the lubricating oil, ρ is the density of the lubricating oil, and T in is the lubricating oil temperature at the radiator inlet, T out is the outlet lubricating oil temperature of the radiator, T m is the average temperature of the lubricating oil at the inlet and outlet of the radiator, It represents the integration operation of the function from the inlet temperature to the outlet temperature, and the subscript T represents the physical property parameter when the temperature is T.

[0059] Step S500: Perform oil side flow resistance characteristic tests on air-lubricant radiator products that have experienced different flow resistance failures, obtain product test data results, and calculate the upper limit k of the proportional coefficient parameter. 上限 and the lower limit k of the proportionality coefficient parameter 下限 , the flow resistance fault includes the flow resistance increase fault and the flow resistance decrease fault;

[0060] Upper limit k of proportionality coefficient parameter 上限 The specific acquisition method is: collect air-lubricating oil radiator products with increased flow resistance caused by blockage, scaling, etc. in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet. Divide the test data results of the product with abnormally increased flow resistance by the calculation results of the fitting relationship, obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation of the proportional coefficient. Set the upper limit of the proportional coefficient parameter k 上限 As the reference upper limit of the proportionality coefficient between the abnormally increased flow resistance and the calculated flow resistance pressure difference, the upper limit of the proportionality coefficient parameter k 上限 is the mean value of the proportionality coefficient minus the standard deviation of the proportionality coefficient.

[0061] The lower limit of the proportional coefficient parameter k 下限 The specific acquisition method is: collect air-lubricating oil radiator products with flow resistance reduction failures such as cracks and leaks in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet. Divide the test data results of the product with abnormally reduced flow resistance by the calculation results of the fitting relationship, obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation. Set the lower limit of the proportional coefficient k 下限 As the reference lower limit of the proportionality coefficient between the abnormally reduced flow resistance and the calculated flow resistance pressure difference, the lower limit of the proportionality coefficient parameter k 下限 is the mean + standard deviation of the proportionality coefficient.

[0062] Step S600: When the engine equipped with the air-lubricating oil radiator is running normally, the normal operation data of the air-lubricating oil radiator is collected and the pressure difference ΔP is corrected by the lubricating oil side. 理论修正 Calculate the corrected flow resistance proportional coefficient k and determine whether the corrected flow resistance proportional coefficient k is within the upper limit k of the proportional coefficient parameter 上限 and the lower limit k of the proportionality coefficient parameter 下限 If so, the k value is considered normal and the air-lubricating oil radiator is working normally.

[0063] The specific method for obtaining the corrected flow resistance proportional coefficient k is as follows: arrange temperature and pressure measuring points at the inlet and outlet of the lubricating oil side of the air-lubricating oil radiator, arrange lubricating oil volume flow measuring points at the inlet of the air-lubricating oil radiator, process the monitoring data of the measuring points through the engine control system, and calculate the corrected pressure difference △P on the lubricating oil side according to the fitting relationship and the calculation formula of the lubricating oil temperature rise correction coefficient θ 理论修正 , the actual pressure difference △P on the lubricating oil side obtained through the radiator inlet and outlet pressure measuring points 真实 Corrected pressure difference with lubricating oil side △P 理论修正 Divide the actual flow resistance and the corrected flow resistance after theoretical calculation to obtain the proportional coefficient k, k = △P 真实 / △P 理论修正 .

[0064] When the k value is abnormal for 5 consecutive operating points or for 1 hour, it is considered that the air-lubricating oil radiator is faulty and needs to be returned to the factory for repair.

[0065] In summary, the present invention conducts a test on the flow resistance characteristics of the oil side of the newly processed air-lubricating oil radiator, draws a change curve through the test data table and removes abnormal data, and then calculates the oil side pressure difference △P according to the change curve, and then calculates the oil temperature rise correction coefficient θ to correct the oil side pressure difference △P, and obtains the oil side corrected pressure difference △P 理论修正 Then, the oil side flow resistance characteristic test was carried out on the actual working air-lubricating oil radiator products, the product test data results were obtained and the upper limit of the proportional coefficient parameter k was calculated. 上限 and the lower limit k of the proportionality coefficient parameter 下限 , by correcting the differential pressure △P on the lubricating oil side 理论修正 Calculate the corrected flow resistance proportional coefficient k, and calculate the flow resistance proportional coefficient k and the proportional coefficient parameter upper limit k 上限 and the lower limit k of the proportionality coefficient parameter 下限 The relationship between the corresponding air-lubricating oil radiator and the load condition is used to determine whether the air-lubricating oil radiator is abnormal.

[0066] It has the following advantages:

[0067] 1. Use pressure, temperature and other sensors to obtain performance data and compare them with theoretical calculated values ​​to indirectly monitor whether the air-lubricating oil radiator has failed, avoiding the need to open a cover on the engine casing and reducing the weight of the engine. Workers do not need to stop the machine for inspection, which improves the efficiency of workers' inspection.

[0068] 2. Through performance data monitoring, real-time monitoring can be achieved. When the air-lubricating oil radiator fails, it can be repaired immediately to avoid more serious damage.

[0069] 3. In addition to discovering radiator oil leakage faults, testing through performance data can also detect faults such as blockage inside the radiator that cause increased flow resistance, which workers cannot detect by visually inspecting the product appearance.

[0070] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0071] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for monitoring faults of an aircraft engine air lubricating oil radiator, characterized in that: include: Set up an air-lubricating oil radiator flow resistance characteristic test bench to carry out the oil side flow resistance characteristic test on the newly processed air-lubricating oil radiator. After the test is completed, all the flow resistance characteristic data collected during the test are recorded in the test record sheet; According to the flow resistance characteristic data in the test record table, draw a curve chart of the lubricating oil side pressure difference △P of the air lubricating oil radiator changing with the lubricating oil temperature T and the lubricating oil volume flow rate qv, obtain the overall change trend of each state point of the change curve chart by interpolation, and judge whether there is a state point in the change curve chart where the lubricating oil side pressure difference result deviates from the overall trend; if so, remove the abnormal data; The lubricating oil side pressure difference △P, lubricating oil temperature T and lubricating oil volume flow rate qv data in the change curve diagram after deleting abnormal data are obtained, and the relationship between the lubricating oil side pressure difference △P and the lubricating oil temperature T and the lubricating oil volume flow rate qv is fitted by a polynomial, and the fitting relationship is obtained as follows: △P(T,qv)=F(T,qv); the dynamic viscosity and temperature of the lubricating oil are obtained according to the lubricating oil type, the inlet lubricating oil temperature, the outlet lubricating oil temperature and the average inlet and outlet lubricating oil temperature of the radiator during the test are obtained according to the test record sheet, and the lubricating oil temperature rise correction coefficient θ is calculated. The lubricating oil side pressure difference △P is corrected according to the lubricating oil temperature rise correction coefficient θ to obtain the lubricating oil side corrected pressure difference △P 理论修正 ; The oil side flow resistance characteristic test was carried out on the air-lubricating oil radiator products that had different flow resistance failures, and the product test data results were obtained and the upper limit k of the proportional coefficient parameter was calculated. 上限 and the lower limit k of the proportionality coefficient parameter 下限 , the flow resistance fault includes the flow resistance increase fault and the flow resistance decrease fault; When the engine equipped with air-lubricating oil radiator is running normally, collect the normal operation data of the air-lubricating oil radiator and correct the pressure difference △P on the lubricating oil side. 理论修正 Calculate the corrected flow resistance proportional coefficient k and determine whether the corrected flow resistance proportional coefficient k is within the upper limit k of the proportional coefficient parameter 上限 and the lower limit k of the proportionality coefficient parameter 下限 If so, the k value is considered normal and the air-lubricating oil radiator is working normally.

2. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The lubricating oil side flow resistance characteristic test is specifically as follows: Arrange temperature measuring points at the lubricating oil side inlet of the radiator, volume flow measuring points at the inlet of the radiator, and pressure measuring points at the inlet and outlet of the radiator; The flow resistance characteristic test of the air-lubricating oil radiator carried out covers all the working conditions in the test record table; different working conditions in the test record table are tested separately, and for the test under each working condition, the inlet temperature data, inlet volume flow data, inlet and outlet pressure data of the radiator are recorded after the test data is stable for 3 minutes; the test requires that no fluid flows on the air side and only the lubricating oil side; considering the influence of heat leakage, the outer surface of the air-lubricating oil radiator is covered with insulation material.

3. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 2, characterized in that: The test record table requires that the test conditions carried out by the air-lubricating oil radiator can cover M types of lubricating oil temperatures × N types of lubricating oil volume flow rates; The highest and lowest values ​​of the M types of lubricating oil temperatures selected in the test record table are derived from the highest and lowest temperatures of the air-lubricating oil radiator on the engine; the maximum value of the N types of lubricating oil volume flow rates selected in the test record table is derived from the maximum value that may occur in the air-lubricating oil radiator on the engine; The minimum value of the lubricating oil volume flow rate is obtained by multiplying the maximum value of the N types of lubricating oil volume flow rates by a correction coefficient, and the correction coefficient is between 0.1 and 0.

4.

4. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The specific method for judging whether there is a state point in the change curve diagram where the lubricating oil side pressure difference result deviates from the overall trend is: obtaining the overall interpolation in the overall change trend, and judging each state point separately, when the difference between the interpolation of a state point and the overall interpolation is greater than the set threshold, if so, the state point is judged to be abnormal data.

5. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The fitting relationship is: △P 理论 (T,qv)=p00+p10*T+p01*qv+p20*T^2+p11*T*qv+p02*qv^2+p30*T^3+p21*T^2*qv+p12*T*qv^2.

6. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: Corrected differential pressure △P on the lubricating oil side under the above lubricating oil temperature rise conditions 理论修正 = lubricating oil side pressure difference △P×θ; The calculation formula of the lubricating oil temperature rise correction coefficient θ is: Where θ is the correction factor for the temperature rise of the lubricating oil in the pressure difference, μ is the dynamic viscosity of the lubricating oil, ρ is the density of the lubricating oil, and T in is the lubricating oil temperature at the radiator inlet, T out is the outlet lubricating oil temperature of the radiator, T m is the average temperature of the lubricating oil at the inlet and outlet of the radiator, It represents the integration operation of the function from the inlet temperature to the outlet temperature, and the subscript T represents the physical property parameter when the temperature is T.

7. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The upper limit k of the proportionality coefficient parameter 上限 The specific acquisition method is as follows: collect air-lubricating oil radiator products with increased flow resistance caused by blockage, scaling, etc. in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet; divide the test data results of the product with abnormally increased flow resistance by the calculation results of the fitting relationship to obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation of the proportional coefficient; set the upper limit k of the proportional coefficient parameter 上限 As the reference upper limit of the proportionality coefficient between the abnormally increased flow resistance and the calculated flow resistance pressure difference, the upper limit of the proportionality coefficient parameter k 上限 is the mean value of the proportionality coefficient minus the standard deviation of the proportionality coefficient.

8. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The lower limit k of the proportionality coefficient parameter 下限 The specific acquisition method is as follows: collect air-lubricating oil radiator products with flow resistance reduction failures such as cracks and leakage in the accessory factory, with the number of products being no less than 2, and carry out the flow resistance characteristic test on the lubricating oil side according to the requirements of the test record sheet; divide the test data results of the product with abnormally reduced flow resistance by the calculation results of the fitting relationship to obtain a series of proportional coefficients of flow resistance pressure difference, and calculate the average value and standard deviation; the lower limit k of the proportional coefficient is 下限 As the reference lower limit of the proportionality coefficient between the abnormally reduced flow resistance and the calculated flow resistance pressure difference, the lower limit of the proportionality coefficient parameter k 下限 is the mean + standard deviation of the proportionality coefficient.

9. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: The specific method for obtaining the corrected flow resistance proportional coefficient k is as follows: temperature and pressure measuring points are arranged at the inlet and outlet of the lubricating oil side of the air-lubricating oil radiator, and a lubricating oil volume flow measuring point is arranged at the inlet of the air-lubricating oil radiator, and the monitoring data of the measuring points are processed by the control system of the engine, and the corrected pressure difference ΔP on the lubricating oil side is calculated according to the fitting relationship and the calculation formula of the lubricating oil temperature rise correction coefficient θ 理论修正 , the actual pressure difference △P on the lubricating oil side obtained through the radiator inlet and outlet pressure measuring points 真实 Corrected pressure difference with lubricating oil side △P 理论修正 Divide the actual flow resistance and the corrected flow resistance after theoretical calculation to obtain the proportional coefficient k, k = △P 真实 / △P 理论修正 .

10. The method for monitoring faults of an aircraft engine air-oil radiator according to claim 1, characterized in that: When the k value is abnormal for 5 consecutive operating points or for 1 hour, it is considered that the air-lubricating oil radiator is faulty and needs to be returned to the factory for repair.

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