A calculation and correction method for bearing cavity temperature field

Abstract

The present application belongs to the technical field of aviation engine lubricating oil system, and particularly relates to a bearing cavity temperature field calculation and correction method. It includes: step one, correcting the lubricating oil system parameters; step two, performing thermal analysis calculation and correction on each bearing cavity, including: S21, correcting the calculation formula of the fulcrum bearing heat generation; S22, correcting the heat exchange method of the inner and outer rings of the fulcrum bearing; S23, correcting the stirring heat loading method; S24, correcting the friction heat loading method; S25, correcting the heat transfer coefficient of the inner wall of the bearing cavity. The bearing cavity temperature field calculation and correction method of the present application can quickly obtain accurate bearing cavity temperature calculation results and improve calculation efficiency; it can more accurately determine the heat exchange boundary conditions of the oil and gas environment in the bearing cavity, make the bearing cavity temperature calculation more refined, and improve the authenticity and accuracy of the bearing cavity thermal analysis calculation model.

Description

Technical Field

[0001] The present application belongs to the technical field of aviation engine lubricating oil systems, and in particular relates to a method for calculating and correcting a bearing cavity temperature field. Background Art

[0002] Compared with the third-generation aircraft, the number of onboard electronic equipment has increased, the heat generation power has continued to increase, and the heat generation has increased. At the same time, the engine performance has improved, the heat load of the lubricating oil system has increased, and the aircraft fuel inlet temperature has increased. The lubricating oil system design needs to be more refined. The calculation accuracy of the temperature field of the bearing cavity of the lubricating oil system affects the determination of the engine fuel and lubricating oil system heat dissipation plan and the determination of the aircraft engine coordinated thermal management plan.

[0003] The existing domestic lubricating oil system bearing cavity temperature field calculation is mainly based on theories such as flat plate convection heat transfer. Since the temperature distribution in the bearing cavity is difficult to measure, the bearing cavity temperature field calculation method based on theoretical analysis and calculation has large errors, resulting in large errors in the temperature distribution in the bearing cavity. In order to meet the requirements of improving the accuracy of bearing cavity temperature field calculation required by the increase in fuel inlet temperature of the fourth-generation aircraft, the previous thermal analysis and calculation capabilities of the lubricating oil system can no longer meet the use requirements. Therefore, the bearing cavity temperature field calculation is corrected according to the temperature measurement data of the entire aircraft lubricating oil system, forming a bearing cavity temperature field calculation correction method.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned deficiencies of the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a method for calculating and correcting the temperature field of a bearing cavity, so as to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A method for calculating and correcting a bearing cavity temperature field, comprising:

[0008] Step 1: Modify the lubricating oil system parameters;

[0009] Step 2: Perform thermal analysis calculation and correction on each bearing cavity, including:

[0010] S21. Modify the calculation formula for the heat generation of the pivot bearing;

[0011] S22. Modify the heat exchange method of the inner and outer rings of the pivot bearing;

[0012] S23, modifying the stirring heat loading method;

[0013] S24, modifying the friction heat loading method;

[0014] S25. Correct the heat transfer coefficient of the inner wall of the bearing cavity.

[0015] In at least one embodiment of the present application, in step 1, the modifying of the lubricating oil system parameters includes:

[0016] According to the test results of the trial run, by adjusting the thermal analysis model of the lubricating oil system, the deviation between the calculated values ​​of the lubricating oil supply temperature, the front cavity return oil temperature, the middle cavity return oil temperature, the rear cavity return oil temperature and the total return oil temperature and the test values ​​of the trial run test data is within a predetermined range, thereby ensuring that the deviation between the calculated value of the total heating value of the bearing cavity and the actual value is within a predetermined range.

[0017] In at least one embodiment of the present application, in S21, the step of modifying the calculation formula for the heat generation of the pivot bearing includes:

[0018] Define the ball bearing correction calculation coefficient as 0.45;

[0019] Define the roller bearing correction calculation coefficient as 0.4;

[0020] The correction calculation coefficient for counter-rotating bearings is defined as 0.95.

[0021] In at least one embodiment of the present application, in S22, the modifying of the heat exchange mode of the inner and outer rings of the pivot bearing includes:

[0022] It is defined that the stirring heat generated by the bearing accounts for 80% of the heat generated by the pivot bearing, and the stirring heat is loaded in the form of convection heat transfer;

[0023] It is defined that the friction heat generated by the bearing accounts for 20% of the heat generated by the fulcrum bearing, and the friction heat is loaded in the form of heat flux density.

[0024] In at least one embodiment of the present application, in S23, the modifying the stirring heat loading mode includes:

[0025] The stirring heat is loaded onto the inner and outer rings of the bearing by convection heat transfer. The heat transfer temperature of the inner and outer rings of the bearing is defined as the sum of half of the temperature rise of the lubricating oil caused by the stirring heat and the oil supply temperature. When calculating the lubricating oil temperature rise using the stirring heat, the lubricating oil flow rate entering the bearing is calculated according to the oil collection efficiency test.

[0026] In at least one embodiment of the present application, in S24, the modifying the friction heat loading mode includes:

[0027] Frictional heat is loaded onto the inner and outer rings of the bearing in the form of heat flux density, of which the inner ring of the roller bearing accounts for 9%, the outer ring of the roller bearing accounts for 11%, the inner ring of the ball bearing accounts for 8%, and the outer ring of the ball bearing accounts for 12%.

[0028] In at least one embodiment of the present application, in S25, the correcting the heat transfer coefficient of the inner wall of the bearing cavity includes:

[0029] According to the measured value of the bearing cavity temperature, the boundary heat exchange temperature in the bearing cavity is corrected so that the deviation between the calculated value of the bearing cavity temperature and the measured value of the bearing cavity temperature is within a predetermined range;

[0030] According to the measured value of the bearing cavity wall temperature, the boundary heat transfer coefficient of the bearing cavity is corrected, specifically:

[0031] The correction of the heat transfer coefficient at the plate in the bearing cavity includes changing the heat transfer coefficient at the H3 plate in the front cavity of the WS-15 engine to 2200 and the heat transfer coefficient at the H4 plate to 1500.

[0032] The invention has at least the following beneficial technical effects:

[0033] The bearing cavity temperature field calculation and correction method of the present application can quickly obtain accurate bearing cavity temperature calculation results and improve calculation efficiency; it can more accurately determine the heat exchange boundary conditions of the oil and gas environment in the bearing cavity, make the bearing cavity temperature calculation more refined, and improve the authenticity and accuracy of the bearing cavity thermal analysis calculation model. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a flow chart of a method for calculating and correcting the bearing cavity temperature field according to one embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be understood as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0036] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as limiting the scope of protection of this application.

[0037] The following is combined with Figure 1This application is described in further detail.

[0038] This application provides a method for calculating and correcting the bearing cavity temperature field, comprising the following steps:

[0039] Step 1: Modify the lubricating oil system parameters;

[0040] Step 2: Perform thermal analysis calculation and correction on each bearing cavity, including:

[0041] S21. Modify the calculation formula for the heat generation of the pivot bearing;

[0042] S22. Modify the heat exchange method of the inner and outer rings of the pivot bearing;

[0043] S23, modifying the stirring heat loading method;

[0044] S24, modifying the friction heat loading method;

[0045] S25. Correct the heat transfer coefficient of the inner wall of the bearing cavity.

[0046] In the bearing cavity temperature field calculation and correction method of the present application, in step 1, the lubricating oil system parameters are first corrected, including:

[0047] According to the test results of the trial run, by adjusting the thermal analysis model of the lubricating oil system, the deviation between the calculated values ​​of the lubricating oil supply temperature, the front cavity return oil temperature, the middle cavity return oil temperature, the rear cavity return oil temperature and the total return oil temperature and the test values ​​of the trial run test data is within a predetermined range, thereby ensuring that the deviation between the calculated value of the total heating value of the bearing cavity and the actual value is within a predetermined range.

[0048] The bearing cavity temperature field calculation and correction method of the present application corrects the bearing cavity temperature field after the lubricating oil system parameters are corrected. In step 2, thermal analysis calculation and correction are performed on each bearing cavity based on the temperature measurement results of the lubricating oil system special test. Specifically,

[0049] In S21, the calculation formula for the heat generation of the pivot bearing is modified to include:

[0050] Define the ball bearing correction calculation coefficient as 0.45;

[0051] Define the roller bearing correction calculation coefficient as 0.4;

[0052] The correction calculation coefficient for counter-rotating bearings is defined as 0.95.

[0053] The above-mentioned corrected bearing correction calculation coefficient can be further adjusted according to the temperature field calculation results.

[0054] The correction calculation coefficient of each bearing is obtained based on the difference between the heating value of the pivot bearing calculated according to the pivot bearing heating value formula and the actual test result.

[0055] In S22, the heat exchange method of the inner and outer rings of the pivot bearing is modified to include:

[0056] It is defined that the stirring heat generated by the bearing accounts for 80% of the heat generated by the pivot bearing, and the stirring heat is loaded in the form of convection heat transfer;

[0057] It is defined that the friction heat generated by the bearing accounts for 20% of the heat generated by the fulcrum bearing, and the friction heat is loaded in the form of heat flux density.

[0058] The above correction method can be adjusted according to the temperature field calculation results.

[0059] Through the test results of the inner and outer ring temperatures of the bearings during the special test of the lubricating oil system, the proportion of the stirring heat and friction heat generated by the bearings was analyzed.

[0060] In S23, the stirring heat loading mode is modified including:

[0061] The stirring heat (80% of the heat generated by the pivot bearing) is loaded onto the inner and outer rings of the bearing by means of convection heat transfer. The convection heat transfer coefficient is calculated using the bearing convection heat transfer coefficient formula. The heat transfer temperature of the inner and outer rings of the bearing is defined as the sum of half of the temperature rise of the lubricating oil caused by the stirring heat and the oil supply temperature. When calculating the lubricating oil temperature rise using stirring heat, the lubricating oil flow rate entering the bearing is calculated according to the oil collection efficiency test.

[0062] The above correction method can be adjusted according to the temperature field calculation results.

[0063] In S24, the friction heat loading method is modified as follows:

[0064] Frictional heat (20% of the heat generated by the pivot bearing) is loaded onto the inner and outer rings of the bearing in the form of heat flux density, of which the inner ring of the roller bearing accounts for 9%, the outer ring of the roller bearing accounts for 11%, the inner ring of the ball bearing accounts for 8%, and the outer ring of the ball bearing accounts for 12%.

[0065] In S25, the correction of the heat transfer coefficient of the inner wall of the bearing cavity includes:

[0066] According to the measured value of the bearing cavity temperature, the boundary heat exchange temperature in the bearing cavity is corrected so that the deviation between the calculated value of the bearing cavity temperature and the measured value of the bearing cavity temperature is within a predetermined range;

[0067] According to the measured value of the bearing cavity wall temperature, the boundary heat transfer coefficient of the bearing cavity is corrected, specifically:

[0068] The correction of the heat transfer coefficient at the plate in the bearing cavity includes changing the heat transfer coefficient at the H3 plate in the front cavity of the WS-15 engine to 2200 and the heat transfer coefficient at the H4 plate to 1500.

[0069] The bearing cavity temperature field calculation and correction method of the present application finally corrects the heat transfer coefficient of the inner wall of the bearing cavity. The current correction result is: based on the measured value of the bearing cavity temperature and the measured value of the bearing cavity wall temperature, and according to the actual flow path of oil and gas in the bearing cavity, the heat transfer mode of the inner wall of the bearing cavity is corrected, including the heat transfer temperature and the heat transfer coefficient. ① Correct the heat exchange temperature of each boundary in the bearing cavity, such as the boundary that exchanges heat with the bearing cavity temperature, so that the calculated value of the bearing cavity temperature is closer to the measured value; ② Secondly, correct the heat transfer coefficient of each boundary in the bearing cavity, such as the heat transfer coefficient at the flat plate in the bearing cavity. The heat transfer coefficient at the H3 flat plate in the front cavity of the WS-15 engine is modified to 2200, and the heat transfer coefficient at the H4 flat plate is modified to 1500; finally, based on the analysis of the temperature measurement level in the bearing cavity, the heat exchange temperature of the heat exchange boundary of the middle cavity is changed from heat exchange with the bearing cavity temperature to heat exchange with the oil supply temperature, such as H2, H3, H7, H8, H11, H14 in the middle cavity, and H5~H9, H11, H12, H13, H14 in the rear cavity.

[0070] The bearing cavity temperature field calculation correction method of the present application can realize the correction of the bearing cavity temperature field calculation. The nozzle flow capacity under the test state is obtained by measuring the nozzle characteristics and relevant parameters during the core engine test. Through this correction method, the deviation between the actual temperature value in the bearing cavity and the corrected calculated value is mostly within ±5°C, and the maximum does not exceed ±10°C. After correction, the calculation accuracy is greatly improved. This method has provided accurate guidance in the design process of the lubricating oil system of subsequent batches of engines and other types of engines, the troubleshooting process, the flight heat management coordination process, and the design process of the bearing cavity tester scheme, greatly improving the accuracy of the calculation.

[0071] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for calculating and correcting the bearing cavity temperature field, characterized in that: include: Step 1: Modify the lubricating oil system parameters; Step 2: Perform thermal analysis calculation and correction on each bearing cavity, including: S21. Modify the calculation formula for the heat generation of the pivot bearing; S22. Modify the heat exchange method of the inner and outer rings of the pivot bearing; S23, modifying the stirring heat loading mode; S24, modifying the friction heat loading method; S25, correcting the heat transfer coefficient of the inner wall of the bearing cavity; In S21, the correction of the calculation formula for the heat generation of the pivot bearing includes: Define the ball bearing correction calculation coefficient as 0.45; Define the roller bearing correction calculation coefficient as 0.4; Define the correction calculation coefficient of the counter-rotating bearing as 0.95; In S22, the modification of the heat exchange mode of the inner and outer rings of the pivot bearing includes: It is defined that the stirring heat generated by the bearing accounts for 80% of the heat generated by the pivot bearing, and the stirring heat is loaded in the form of convection heat transfer; It is defined that the friction heat generated by the bearing accounts for 20% of the heat generated by the fulcrum bearing, and the friction heat is loaded in the form of heat flux density.

2. The calculation and correction method for the bearing cavity temperature field according to claim 1 is characterized in that: In step 1, the correction of the lubricating oil system parameters includes: According to the test results of the trial run, by adjusting the thermal analysis model of the lubricating oil system, the deviation between the calculated values ​​of the lubricating oil supply temperature, the front cavity return oil temperature, the middle cavity return oil temperature, the rear cavity return oil temperature and the total return oil temperature and the test values ​​of the trial run test data is within a predetermined range, thereby ensuring that the deviation between the calculated value of the total heating value of the bearing cavity and the actual value is within a predetermined range.

3. The calculation and correction method for the bearing cavity temperature field according to claim 2 is characterized in that: In S23, the modification of the stirring heat loading mode includes: The stirring heat is loaded onto the inner and outer rings of the bearing by convection heat transfer. The heat transfer temperature of the inner and outer rings of the bearing is defined as the sum of half of the temperature rise of the lubricating oil caused by the stirring heat and the oil supply temperature. When calculating the lubricating oil temperature rise using the stirring heat, the lubricating oil flow rate entering the bearing is calculated according to the oil collection efficiency test.

4. The calculation and correction method for the bearing cavity temperature field according to claim 3 is characterized in that: In S24, the modification of the friction heat loading mode includes: Frictional heat is loaded onto the inner and outer rings of the bearing in the form of heat flux density, of which the inner ring of the roller bearing accounts for 9%, the outer ring of the roller bearing accounts for 11%, the inner ring of the ball bearing accounts for 8%, and the outer ring of the ball bearing accounts for 12%.

5. The calculation and correction method for the bearing cavity temperature field according to claim 4 is characterized in that: In S25, the correction of the heat transfer coefficient of the inner wall of the bearing cavity includes: According to the measured value of the bearing cavity temperature, the boundary heat exchange temperature in the bearing cavity is corrected so that the deviation between the calculated value of the bearing cavity temperature and the measured value of the bearing cavity temperature is within a predetermined range; According to the measured value of the bearing cavity wall temperature, the boundary heat transfer coefficient of the bearing cavity is corrected, specifically: The correction of the heat transfer coefficient at the plate in the bearing cavity includes changing the heat transfer coefficient at the H3 plate in the front cavity of the WS-15 engine to 2200 and the heat transfer coefficient at the H4 plate to 1500.

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