A method and system for predicting the temperature rise of aviation bearings based on a high-temperature test device

Abstract

The present invention relates to the technology of predicting the temperature rise of aviation bearings, and discloses a method and system for predicting the temperature rise of aviation bearings based on a high-temperature test device. The method includes: obtaining the working clearance through thermodynamics theory; constructing the contact load-deformation relationship and contact load-driving force relationship between the rolling elements and the raceways of the inner and outer rings to calculate the viscous resistance; constructing the bearing quasi-dynamic load force balance equation of thermal-fluid-solid coupling; iteratively solving the bearing quasi-dynamic load force balance equation and calculating the heat generation of the bearing according to the solution results; constructing the bearing thermal boundary conditions with the results of the bearing high-temperature simulation test for heat generation distribution, establishing the bearing thermal balance equation through the distribution results and the calculated contact position thermal resistance, and iteratively solving to obtain the temperature rise results. The present invention can quickly obtain the temperature distribution of each part of the bearing, providing a more comprehensive theoretical method for the internal structure optimization design of aviation bearings and the matching design of bearings with shafts and bearing seats.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical engineering, relates to the technology of predicting the temperature rise of aviation bearings, and particularly relates to a method and system for predicting the temperature rise of aviation bearings based on a high-temperature test device. Background Art

[0002] As one of the key components of an aeroengine, an aviation bearing is mainly used to support the high and low rotor systems and transmit loads, playing a crucial role in the reliable operation of the engine. With the continuous breakthrough and improvement of the extreme performance of aeroengines, higher performance requirements are put forward for aviation bearings. Currently, problems such as wear, burn and seizure of aeroengine bearings caused by high temperature, which are early failures of bearings, have become one of the key restrictive factors limiting the development of engines towards long life, strong extreme performance and high reliability, thus affecting the life, load-bearing capacity, reliability and dynamic performance of aeroengines.

[0003] In recent years, some scholars at home and abroad have carried out a large number of theoretical analysis works on the heat generation and temperature rise of aviation bearings. The heat generation and temperature rise of bearings are mainly obtained by the overall method or the local method. This method is based on the traditional quasi-static model or quasi-dynamic model of bearings. This method does not consider the mutual coupling effects among the internal structure, temperature and lubrication of the bearings, let alone the effects of under-ring oil supply, heat distribution and bearing thermal boundary on the bearing load distribution and motion characteristics, thus it is difficult to accurately reflect the internal motion and heat generation mechanism under the working conditions of the bearings.

[0004] In addition, the current temperature test for aviation bearings is usually carried out based on a bearing tester, which fails to truly simulate the high-temperature environment in the bearing cavity, resulting in low accuracy in evaluating the bearing performance, and thus it is even more difficult to reflect the temperature rise of aviation bearings in the real high-temperature environment in real time.

[0005] Generally speaking, the existing methods for evaluating the temperature of aviation bearings generally first calculate the heat generation of the bearings through empirical formulas, then analyze the temperature field distribution of the bearings through simulation, and finally verify through tests on the bearing tester and the whole engine test of the engine. This method has the following drawbacks: (1) The heat generation and temperature simulation of the bearings do not consider the thermo-fluid-solid coupling effect, resulting in low simulation accuracy; (2) The test on the bearing tester is difficult to simulate the high-temperature working environment, resulting in large test errors; (3) The whole engine test of the engine involves many factors and has a complex structure, making it difficult to accurately evaluate the internal temperature distribution of the bearings, resulting in a large gap between the existing temperature simulation results and test results of aviation bearings, which are difficult to corroborate each other and are not convenient for engineering applications.

[0006] Therefore, there is an urgent need for a method that can quickly and accurately simulate and predict the operating temperature of aviation bearings, so as to explore the operating performance of aviation bearings under the coupling conditions of thermal-fluid-solid multi-physical fields, optimize the design of the internal structure parameters of aviation bearings and reasonably select the external boundary conditions. At the same time, it can also provide more accurate boundary inputs for the design of the bearing cavity structure and the lubricating oil system, so as to improve the operating reliability of the rotor-bearing system. Summary of the Invention

[0007] In order to achieve the purpose of quickly and accurately simulating and predicting the operating temperature of aviation bearings and exploring the operating performance of aviation bearings under the coupling conditions of thermal-fluid-solid multi-physical fields, the present invention discloses a method for predicting the temperature rise of aviation bearings based on a high-temperature test device. The method includes the following steps:

[0008] S1. Heat the test bearing to collect the temperature of the bearing outer ring, use the temperature of the bearing outer ring as the initial operating temperature of each part of the bearing, and obtain the working clearance of the test bearing through thermodynamic theory by using the temperature of the bearing outer ring, the structural parameters and material parameters of the test bearing.

[0009] S2. Construct the contact load-deformation relationship between the rolling elements and the raceways of the rings according to the bearing coordinate system, the working clearance and the oil film thickness, establish the contact load-drag force relationship between the rolling elements and the raceways of the rings under the condition of a given rotational speed of the bearing inner ring, and calculate the viscous resistance borne by the rolling elements according to the angular velocity of the common rotation of the rolling elements and the density of the oil-gas mixture.

[0010] S3. Construct a thermo-fluid-solid coupled bearing quasi-dynamic load force balance equation according to the contact load-deformation relationship, the contact load-drag force relationship, the viscous resistance, the forces and torques between the rolling elements and the pockets of the cage, the forces and torques between the cage and the guiding rings, and the inertial forces and torques of the rolling elements.

[0011] S4. Iteratively solve the bearing quasi-dynamic load force balance equation, and calculate the heat generation of the bearing according to the iterative solution results.

[0012] S5. Construct the bearing thermal boundary conditions according to the results of the bearing high-temperature simulation test, distribute the heat generation of the bearing through the heat generation mechanism, calculate the contact position thermal resistance of the test bearing under the condition of lubricating oil lubrication, establish a bearing heat balance equation through the heat generation distribution results and the contact position thermal resistance, and iteratively solve the bearing heat balance equation to obtain the temperature rise of each part of the bearing.

[0013] Further, in the above step S1, the test bearing is heated to collect the temperature of the outer ring of the bearing, and the temperature of the outer ring of the bearing is used as the initial working temperature of each part of the bearing. According to the thermodynamic theory, the working clearance of the test bearing is obtained by using the temperature of the outer ring of the bearing, the structural parameters and material parameters of the test bearing, including:

[0014] S11. Heat the test bearing to collect the temperature of the outer ring of the bearing, and use the temperature of the outer ring of the bearing as the initial working temperature of the rotating shaft, inner ring, rolling elements, outer ring and bearing housing in the test bearing;

[0015] S12. According to the thermodynamic theory, the thermal expansion amounts of the inner ring, the rolling elements and the outer ring are respectively calculated by using the linear expansion coefficient, part diameter, ambient temperature and initial working temperature, and the temperature condition clearance reduction amount is calculated according to the thermal expansion amounts;

[0016] S13. Calculate the working clearance of the test bearing according to the initial clearance of the bearing, the rotational speed condition clearance reduction amount, the fit condition clearance reduction amount and the temperature condition clearance reduction amount.

[0017] Further, in the above step S2, the contact load-deformation relationship between the rolling elements and the raceways of the rings is constructed according to the bearing coordinate system, the working clearance, the load and the oil film thickness, including:

[0018] S21. Establish the bearing coordinate system, which includes an inertial coordinate system with the center of the outer ring of the test bearing as the origin, an inner ring coordinate system with the center of the inner ring as the origin, and an azimuth coordinate system with the center of each rolling element as the origin;

[0019] S22. Divide each of the rolling elements into multiple slices along the length direction of the rolling element by the slicing method, and establish the oil film thickness and deformation relationship between the slices and the raceways of the rings according to the working clearance and the oil film thickness;

[0020] S23. Use the angular velocity of the ring, the distance between the slice and the ring, the common angular velocity of the rolling elements and the self-angular velocity of the rolling elements to calculate the average slice velocity and the slice sliding velocity between the slice and the raceways of the rings according to the inertial coordinate system, the inner ring coordinate system and the azimuth coordinate system, and establish the oil film thickness and contact load relationship between the slice and the raceways of the rings according to the average slice velocity through the line contact elastohydrodynamic lubrication theory;

[0021] S24. Through the oil film thickness and deformation relationship and the oil film thickness and contact load relationship, construct the contact load-deformation relationship between the rolling elements and the raceways of the rings according to the Hertz contact theory.

[0022] Even further, in the above step S21, the expression of the oil film thickness and deformation relationship is: , where is the distance between the j th rolling element's i th slice and point P on the raceway surface, is the deformation between the th rolling element's j th slice and the raceway, is the deformation caused by the convexity of the rolling element on the th slice, is the angular deviation of the inner ring axis relative to the outer ring axially, is the bearing angular position, w is the oil film thickness between the d th rolling element's

[0023] th slice and the raceway, i is the slice number representing the th slice, is the average slice velocity between the j th rolling element's i th slice and the raceway, is the equivalent elastic modulus of the rolling element and the raceway ， is the equivalent curvature radius of the rolling element and the raceway, is the lubricating oil viscosity, is the viscosity-pressure coefficient, Q ji is the j th rolling element's i th slice's contact load with the raceway, L r is the rolling element length, is the oil film correction coefficient considering the thermal effect.

[0024] Furthermore, in the above step S2, the expression of the contact load - drag force relationship is , where is the drag force between the Q ji th slice of the th rolling element and the raceway,

[0025] Furthermore, in the above step S2, the formula for calculating the viscous resistance borne by the rolling element according to the angular velocity of the rolling element's common rotation and the density of the oil - gas mixture is , where F dj is the viscous resistance,ρ ef is the density of the oil-gas mixture, D m is the pitch diameter of the bearing, C D is the damping coefficient, D w is the diameter of the rolling element, is the angular velocity of the j-th rolling element's common rotation.

[0026] Furthermore, in the above step S3, according to the contact load-deformation relationship, the contact load-driving force relationship, the viscous resistance, the forces and torques between the rolling elements and the cage pockets, the forces and torques between the cage and the guiding rings, and the inertial forces and torques of the rolling elements, a thermo-fluid-solid coupled bearing quasi-dynamic load force balance equation is constructed, including:

[0027] S31. Obtain the forces and torques between the rolling elements and the cage pockets according to the long journal bearing model, obtain the forces and torques between the cage and the guiding rings according to the short journal bearing model, and obtain the inertial forces and torques of the rolling elements during the rotation of the test bearing according to theoretical mechanics;

[0028] S32. Establish a force balance equation and a torque balance equation for the thermo-fluid-solid coupled rolling elements according to the forces and torques between the rolling elements and the cage pockets, the inertial forces and torques of the rolling elements, the contact load-deformation relationship, and the viscous resistance;

[0029] S33. With the cage rotational speed being a constant value as a constraint condition during steady-state operation, establish a force balance equation and a torque balance equation for the thermo-fluid-solid coupled cage according to the forces and torques between the cage and the guiding rings;

[0030] S34. Under the given external load conditions, establish a force balance equation and a torque balance equation for the thermo-fluid-solid coupled inner ring according to the contact load-deformation relationship and the contact load-driving force relationship, and complete the construction of the bearing quasi-dynamic load force balance equation.

[0031] Furthermore, in the above step S5, according to the bearing high-temperature simulation test results, a bearing thermal boundary condition is constructed, the heat generation of the bearing is distributed through the heat generation mechanism, the contact position thermal resistance of the test bearing is calculated under the lubricating oil lubrication condition, and a bearing heat balance equation is established through the bearing heat generation distribution result and the contact position thermal resistance, including:

[0032] S51. Conduct a high-temperature simulation test on the test bearing to obtain the bearing high-temperature simulation test results including the oil supply temperature, the temperature of the bearing outer ring, and the bearing chamber temperature;

[0033] S52. Take the high-temperature simulation test results of the bearing as the thermal boundary conditions, and perform heat generation distribution according to the bearing heat generation, the bearing heat generation position, and the heat transfer ratio.

[0034] S53. Under the lubricating oil lubrication condition, obtain the thermal resistance of the contact position where the lubricating oil flows through by the thermal network method, and establish a bearing heat balance equation through the heat generation distribution result and the thermal resistance of the contact position.

[0035] Furthermore, in the above step S5, the temperature rise of each part on the test bearing is obtained by iteratively solving the bearing heat balance equation, including:

[0036] Iteratively solve the bearing heat balance equation by the Gaussian elimination method and the successive over-relaxation method until the convergence accuracy of the current iteration result and the previous iteration result is less than the threshold value, and output the temperature rise of each part on the test bearing.

[0037] The embodiment of the present invention also provides an aviation bearing temperature rise prediction system based on a high-temperature test device, and the system includes a bearing high-temperature simulation test device, a working clearance calculation module, a first construction module, a viscous resistance calculation module, a second construction module, a bearing heat generation acquisition module, and a temperature rise calculation module.

[0038] Among them, the bearing high-temperature simulation test device is used to perform a high-temperature simulation test on the test bearing; the working clearance calculation module is used to obtain the working clearance of the test bearing according to the temperature of the bearing outer ring through thermodynamic theory; the first construction module is used to construct the contact load-deformation relationship and the contact load-driving force relationship; the viscous resistance calculation module is used to calculate the viscous resistance borne by the rolling elements according to the common angular velocity of the rolling elements and the density of the oil-gas mixture; the second construction module is used to construct a bearing quasi-dynamic load force balance equation of thermal-fluid-solid coupling; the bearing heat generation acquisition module is used to iteratively solve the bearing quasi-dynamic load force balance equation, and calculate the bearing heat generation according to the iterative solution result; the temperature rise calculation module is used to construct the bearing thermal boundary conditions according to the bearing high-temperature simulation test results, distribute the bearing heat generation through the heat generation mechanism, calculate the thermal resistance of the contact position of the test bearing under the lubricating oil lubrication condition, establish a bearing heat balance equation through the bearing heat generation distribution result and the thermal resistance of the contact position, and iteratively solve the bearing heat balance equation to obtain the temperature rise of each part on the bearing.

[0039] The method of the present invention simulates the high-temperature working state of an aviation bearing, considers the influence of thermal conditions during the bearing operation on bearing clearance, load distribution, speed distribution, and lubrication characteristics, and proposes a bearing temperature rise prediction method based on the thermal-fluid-solid coupling effect according to the heat distribution law and heat exchange law inside the bearing. Based on this method, rapid iterative optimization of the aviation bearing structure can be achieved, and a more accurate theoretical basis can be provided for the selection of the fit between the bearing and the shaft and the bearing housing, realizing the temperature rise test assessment of the aviation bearing in a high-temperature environment. This method has the following advantages:

[0040] 1) The test simulation device can simulate the high-temperature working environment of an aviation bearing close to the actual situation. It directly heats the temperature of the bearing periphery by means of electric heating, with a fast heating speed and high temperature control accuracy, which is convenient for test implementation and provides an accurate thermal boundary for the temperature field analysis of the aviation bearing under high-temperature conditions;

[0041] 2) This method considers the influence of thermal-mechanical conditions on the bearing load-carrying characteristics and the influence of the lubrication state of each contact pair on the bearing motion characteristics, combines the heat distribution law and heat exchange law inside the aviation bearing, and obtains more accurate bearing heat generation and temperature rise under the condition of thermal-fluid-solid coupling. It can quickly and accurately obtain the bearing temperature distribution during the bearing structure optimization design, providing a more accurate and reasonable basis for the selection of bearing fit parameters and external oil supply parameters;

[0042] 2) This method is easy to be realized in a process flow and is compiled into a modular calculation program. Combining with the results of the bearing high-temperature simulation test, it can realize the real-time temperature rise prediction of the aviation bearing in a high-temperature environment, providing support for the temperature rise test assessment of the bearing in a high-temperature environment outside the engine whole-machine test and reducing the test cost. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0044] Figure 1 It is the flowchart of the aviation bearing temperature rise prediction method based on a high-temperature test device disclosed in the embodiments of the present invention;

[0045] Figure 2 It is the principle block diagram of the aviation bearing temperature rise prediction method based on a high-temperature test device disclosed in the embodiments of the present invention;

[0046] Figure 3 It is the schematic diagram of the bearing coordinate system disclosed in the embodiments of the present invention;

[0047] Figure 4Schematic diagram of the displacement of rolling elements disclosed in the embodiments of the present invention;

[0048] Figure 5 Schematic diagram of the thermal network model of the aviation test bearing disclosed in the embodiments of the present invention;

[0049] Figure 6 Result of the heat transfer coefficient matrix of the aviation cylindrical bearing disclosed in the embodiments of the present invention, that is, schematic diagram of the temperature rise of each part on the bearing;

[0050] Figure 7 Architecture diagram of the aviation bearing temperature rise prediction system based on the high-temperature test device disclosed in the embodiments of the present invention;

[0051] Figure 8 Schematic diagram of the bearing high-temperature simulation test device disclosed in the embodiments of the present invention;

[0052] Among them, 701 is the bearing high-temperature simulation test device; 702 is the working clearance calculation module; 703 is the first construction module; 704 is the viscous resistance calculation module; 705 is the second construction module; 706 is the bearing heat generation acquisition module; 707 is the temperature rise calculation module 607; 10 is the bearing support; 20 is the first lead joint; 30 is the second lead joint; 40 is the graphite seal; 50 is the rotor assembly; 60 is the oil supply nozzle; 70 is the test bearing; 80 is the oil retaining nut; 90 is the electric heater; 100 is the heat insulation cover plate; 110 is the control system. Detailed implementation manners

[0053] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following specific examples illustrate the implementation manners of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features of the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0054] The embodiments of the present invention disclose an aviation bearing temperature rise prediction method based on a high-temperature test device. Refer to Figure 1 and Figure 2 As shown, the method includes the following steps:

[0055] S1. Heat the test bearing to collect the temperature of the bearing outer ring, use the temperature of the bearing outer ring as the initial working temperature of each part of the bearing, and obtain the working clearance of the test bearing through thermodynamic theory by using the temperature of the bearing outer ring, the structural parameters and material parameters of the test bearing.

[0056] S2. Construct the contact load-deformation relationship between the rolling elements and the raceways of the rings according to the bearing coordinate system, the working clearance and the oil film thickness, establish the contact load-drag force relationship between the rolling elements and the raceways of the rings under the given rotational speed condition of the bearing inner ring, and calculate the viscous resistance borne by the rolling elements according to the angular velocity of the rolling element common rotation angle and the density of the oil-gas mixture.

[0057] S3. Construct the quasi-dynamic load force balance equation of the thermo-fluid-solid coupled bearing according to the contact load-deformation relationship, the contact load-drag force relationship, the viscous resistance, the forces and torques between the rolling elements and the pockets of the cage, the forces and torques between the cage and the guiding ring, and the inertial forces and torques of the rolling elements.

[0058] S4. Iteratively solve the quasi-dynamic load force balance equation of the bearing, and calculate the heat generation of the bearing according to the iterative solution results.

[0059] S5. Construct the thermal boundary conditions of the bearing according to the results of the bearing high-temperature simulation test, distribute the heat generation of the bearing through the heat generation mechanism, calculate the thermal resistance at the contact position of the test bearing under the lubrication condition of the lubricating oil, establish the bearing heat balance equation through the heat generation distribution results and the thermal resistance at the contact position, and iteratively solve the bearing heat balance equation to obtain the temperature rise of each part on the bearing.

[0060] In a feasible embodiment of the above step S1, heating the test bearing to collect the temperature of the bearing outer ring, using the temperature of the bearing outer ring as the initial working temperature of each part of the bearing, and obtaining the working clearance of the test bearing through thermodynamic theory by using the temperature of the bearing outer ring, the structural parameters and material parameters of the test bearing includes:

[0061] S11. Heat the test bearing to collect the temperature of the bearing outer ring, and use the temperature of the bearing outer ring as the initial working temperature of the rotating shaft, inner ring, rolling elements, outer ring and bearing housing in the test bearing. The initial working temperatures of each component in the test bearing can be expressed as ; where, T S is the temperature of the rotating shaft, T 2 is the temperature of the inner ring, T r is the temperature of the rolling elements, T 1 is the temperature of the outer ring, T h is the temperature of the bearing housing.

[0062] S12. According to the thermodynamic theory, the thermal expansion amounts of the inner ring, the rolling elements, and the outer ring are calculated respectively using the linear expansion coefficient, the part diameter, the ambient temperature, and the initial operating temperature, and the reduction amount of the clearance under temperature conditions is calculated based on the thermal expansion amounts. The formula for the thermal expansion amount of each part is as follows: , where , and are the thermal expansion amounts of the inner ring, the rolling elements, and the outer ring respectively under the initial operating temperature T. , , are the linear expansion coefficients of the inner raceway, the rolling elements, and the outer raceway respectively. D 2 , D w , D 1 are the diameters of the inner ring, the rolling elements, and the outer ring respectively. T a is the ambient temperature, that is, the atmospheric temperature after the assembly of each part of the test bearing. The reduction amount of the clearance under temperature conditions can be calculated through the formula , which is also the reduction amount of the working clearance after the thermal expansion deformation of the test bearing under heating conditions.

[0063] S13. Calculate the working clearance of the test bearing according to the initial clearance of the bearing, the reduction amount of the clearance under speed conditions, the reduction amount of the clearance under fit conditions, and the reduction amount of the clearance under temperature conditions. Among them, the working clearance P d of the test bearing can be calculated through the formula , where P d0 is the initial clearance of the bearing, is the reduction amount of the clearance caused by speed (i.e., the reduction amount of the clearance under speed conditions), is the reduction amount of the clearance caused by fit (i.e., the reduction amount of the clearance under fit conditions). The reduction amount of the clearance under speed conditions and the reduction amount of the clearance under fit conditions can both be calculated according to the traditional formula.

[0064] Furthermore, in the above step S2, the contact load-deformation relationship between the rolling elements and the raceways of the ring is constructed according to the bearing coordinate system, the working clearance, the load, and the oil film thickness, including:

[0065] S21. Establish the bearing coordinate system, which includes an inertial coordinate system with the center of the outer ring of the test bearing as the origin, an inner ring coordinate system with the center of the inner ring as the origin, and an azimuth coordinate system with the center of each rolling element as the origin. In specific implementation, as shown in Figure 3 , an inertial coordinate system is established with the center of the outer ring as the origin , , and an inner ring coordinate system is established with the center of the inner ring as the origin Establish the inner ring coordinate system , with the center of the rolling element as the origin Establish the azimuth coordinate system with it as the origin .

[0066] S22. Divide each of the rolling elements into multiple slices along the length direction of the rolling element by the slicing method, and establish the relationship between the oil film thickness and deformation between the slices and the raceway of the ring according to the working clearance and the oil film thickness.

[0067] More specifically, as shown in Figure 4 , divide the j rolling element along its length direction into N slices, then the distance between the j point on the i th slice of the th rolling element and the P point on the surface of the ring is . At the same time, considering the surface modification of the rolling element, the skew of the rolling element and the oil film thickness, the relationship between the deformation amount and the oil film thickness between the j th rolling element's i th slice and the ring can be expressed as:

[0068] , where is the distance between the j point on the i th slice of the th rolling element and the P point on the surface of the ring, is the deformation amount between the j th rolling element's i-th slice and the ring, is the deformation generated by the convexity of the rolling element on the i-th slice, is the angular deviation of the inner ring axis of the bearing relative to the axial direction of the outer ring of the bearing, is the angular position of the bearing, is the oil film thickness between the w th rolling element's i-th slice and the ring, i is the slice number indicating the i-th slice, d is the working clearance of the bearing.

[0069] More specifically, this expression can be divided into the relationship between the deformation amount and the oil film thickness between the j th rolling element's i th slice and the outer ring and the inner ring respectively, including the following two formulas:

[0070] ;

[0071] , where is the deformation amount between the th rolling element's i-th slice and the outer ring is the deformation amount between the i-th slice of the j-th rolling element and the inner race is the j -th rolling element's i distance between the point on the i-th slice and the point P on the surface of the outer race, 1 and is the j -th rolling element's i distance between the point on the i-th slice and the point on the surface of the inner race P 2 , is the oil film thickness between the i-th slice of the j-th rolling element and the outer race is the oil film thickness between the i-th slice of the j-th rolling element and the inner race

[0072] S23. Using the angular velocity of the race, the distance between the slice and the race, the common angular velocity of the rolling element, and the self-angular velocity of the rolling element, calculate the average slice velocity and the slice sliding velocity of the slice and the raceway of the race according to the inertial coordinate system, the inner ring coordinate system, and the azimuth coordinate system, and establish the relationship between the oil film thickness and the contact load between the slice and the raceway of the race based on the average slice velocity through the line contact elastohydrodynamic lubrication theory

[0073] In specific implementation, considering the effect of the lubricating oil film between the rolling element and the outer race and the inner race, according to the line contact elastohydrodynamic lubrication theory, the oil film thickness j between the i-th slice of the i -th rolling element and the race is obtained respectively by the following Hamrock-Dowson formula

[0074] , where is the average slice velocity of the i-th slice of the j -th rolling element and the race i , is the equivalent elastic modulus of the rolling element and the race is the equivalent curvature radius of the rolling element and the race is the viscosity of the lubricating oil is the viscosity-pressure coefficient Q ji is the j -th rolling element's i contact load between the i-th slice and the race L r is the length of the rolling element is the oil film correction coefficient considering the thermal effect

[0075] The above-mentioned Hamrock-Dowson formula can be divided into expressions for the rolling elements and the outer and inner rings respectively, that is, it includes the following two formulas: , where is the oil film thickness between the i-th slice of the j-th rolling element and the outer ring, is the oil film thickness between the i-th slice of the j-th rolling element and the inner ring, is the j -th rolling element's i -th slice's average velocity with respect to the outer ring's slice, is the j -th rolling element's i -th slice's average velocity with respect to the inner ring's slice, is the equivalent elastic modulus between the rolling element and the outer ring, is the equivalent elastic modulus between the rolling element and the inner ring ， is the equivalent radius of curvature between the rolling element and the outer ring, is the equivalent radius of curvature between the rolling element and the inner ring, is the lubricating oil viscosity, is the viscosity-pressure coefficient, Q 1ji is the j -th rolling element's i -th slice's contact load with the outer ring, Q 2ji is the j -th rolling element's i -th slice's contact load with the inner ring, L r is the rolling element length, is the oil film correction coefficient considering the thermal effect.

[0076] Meanwhile, since the influence of temperature on the oil film thickness cannot be ignored at high speeds, the oil film correction coefficient considering the thermal effect can be calculated through the formula , where , P h is the maximum Hertz pressure, L is the thermal load coefficient, is the equivalent elastic modulus between the rolling element and the ring, s is the slide-roll ratio.

[0077] Among them, the average slice velocity and the slice sliding velocity can be obtained through the analysis of the bearing motion. Specifically, the average slice velocities of the i-th slice of the j-th rolling element with respect to the surfaces of the outer and inner rings can be calculated through the following formulas respectively: j the i -th rolling element's

[0078] ; , where is the angular velocity of the j th rolling element in the common rotation, is the angular velocity of the j th rolling element in the self-rotation, is the angular velocity of the inner ring, is the angular velocity of the outer ring, is the transformation matrix from the azimuth coordinate system to the inertial coordinate system, is the transformation matrix from the inner ring coordinate system to the inertial coordinate system, is the distance from the P 1 to the O rj point on the rolling element in the azimuth coordinate system, is the distance from the P 2 to the O rj point on the rolling element in the azimuth coordinate system, is the distance from the to the O 1 point on the outer ring in the inertial coordinate system, is the distance from the to the O 2 point on the inner ring in the inner ring coordinate system.

[0079] Similarly, the sliding velocities of the j th rolling element's i th slice in contact with the outer and inner raceways are respectively expressed as:

[0080] ; , where is the sliding velocity of the j th rolling element's i th slice in contact with the outer raceway, is the sliding velocity of the j th rolling element's i th slice in contact with the inner raceway.

[0081] Among them, the expression of the contact load - drag force relationship is , is the drag force of the Q ji th slice of the jth rolling element in contact with the raceway, and

[0082] ​Among them, the formula for calculating the viscous resistance borne by the rolling elements according to the angular velocity of the rolling elements and the density of the oil-gas mixture is , where F dj is the viscous resistance, ρ ef is the density of the oil-gas mixture, D m is the pitch diameter of the bearing, C D is the damping coefficient, D w is the diameter of the rolling element, is the angular velocity of the j-th rolling element in its revolution.

[0083] S24. Based on the relationship between the oil film thickness and deformation and the relationship between the oil film thickness and contact load, construct the contact load-deformation relationship between the rolling elements and the raceways of the rings according to Hertz contact theory.

[0084] By constructing several relationships in the above steps S22 to S23, according to Hertz contact theory, for the contact loads and between the j-th rolling element in line contact with the inner ring and the outer ring respectively and the deformation amount, the relationship can be expressed by the following formula:

[0085] , , where K 2 is the load-deformation coefficient between the rolling element and the inner ring, K 1 is the load-deformation coefficient between the rolling element and the outer ring, is the contact load between the j-th rolling element and the inner ring, is the contact load between the j-th rolling element and the outer ring, is the deformation amount between the i-th slice of the j-th rolling element and the outer ring, is the deformation amount between the i-th slice of the j-th rolling element and the inner ring, which depends on the materials of the rolling element and the ring itself and is a given value.

[0086] In the above steps S22 to S24, after the bearing coordinate system is established, when the test bearing is subjected to a certain load, the slice method is used to divide the contact micro-region between the rolling elements and the rings along the length direction. Through the relative position relationship between the rolling elements and the inner ring and the outer ring, calculate the displacement-deformation coordination relationship of each slice of the rolling element, and according to Hertz contact theory, obtain the contact load on the contact surface between each slice of the rolling element and the ring, and then establish the load-deformation relationship between the rolling element and the raceway of the ring.

[0087] Further, in the above step S3, according to the contact load-deformation relationship, the contact load-driving force relationship, the viscous resistance, the forces and moments between the rolling elements and the pockets of the cage, the forces and moments between the cage and the guiding raceway, and the inertial forces and moments of the rolling elements, a thermal-fluid-solid coupled bearing quasi-dynamic load force balance equation is constructed, including:

[0088] S31. Obtain the forces and moments between the rolling elements and the pockets of the cage according to the long sliding bearing model, obtain the forces and moments between the cage and the guiding raceway according to the short sliding bearing model, and obtain the inertial forces and moments of the rolling elements during the rotation of the test bearing according to theoretical mechanics.

[0089] In specific implementation, the interaction forces between the rolling elements and the pockets of the cage are mainly generated by the hydrodynamic pressure effect of the lubricant, which mainly includes normal forces and frictional forces. Since the pocket clearance is much smaller than the length of the rolling element, the forces between the cage pocket and the rolling element can be approximated as a "long sliding bearing" model. Through this long sliding bearing, the forces and moments between the rolling elements and the pockets of the cage can be obtained. Similarly, the interaction forces between the cage and the guiding raceway (where the guiding raceway is the outer race or inner race close to the cage) are mainly generated by the hydrodynamic pressure effect of the lubricant. According to the geometric characteristics of the cage and the guiding raceway, the guiding surface of the raceway and the centering surface of the cage can be regarded as a "short sliding bearing" model. Through this short sliding bearing, the forces and moments between the cage and the guiding raceway can be obtained.

[0090] S32. According to the forces and moments between the rolling elements and the pockets of the cage, the inertial forces and moments of the rolling elements, the contact load-deformation relationship, and the viscous resistance, establish the force balance equation and moment balance equation of the thermal-fluid-solid coupled rolling elements. Taking the j-th rolling element as an example, the force balance equation and moment balance equation of the rolling elements can be expressed as:

[0091] , where F zj is the inertial force in the z direction, F yj is the inertial force in the y direction, G xj is the inertial moment about the x axis, F cj is the normal force between the rolling element and the pocket of the cage, F dj is the viscous resistance, f rcj is the frictional force between the rolling element and the pocket of the cage, L r is the length of the rolling element, is the driving force between the i-th slice and the inner race in the j-th rolling element, is the driving force between the i-th slice and the outer race in the j-th rolling element.

[0092] S33. When operating in a steady state, with the cage rotation speed being a constant value as a constraint condition, establish the force balance equation and moment balance equation of the thermo-fluid-solid coupled cage according to the forces and moments between the cage and the guiding raceway. Specifically, it can be assumed that the cage rotation speed is a constant value during steady-state operation. At this time, the force balance equation and moment balance equation of the cage can be expressed as: , where Z is the number of rolling elements, F cz is the force of the cage in the z direction, F cy is the force of the cage in the y direction, M cx is the moment of the cage about the x axis, is the bearing angular position.

[0093] S34. Under the given external load conditions, establish the force balance equation and moment balance equation of the thermo-fluid-solid coupled inner raceway according to the contact load-deformation relationship and the contact load-driving force relationship, and complete the construction of the bearing quasi-dynamic load force balance equation. Specifically, considering the interaction between the rolling elements and the inner raceway of the bearing, for a bearing with inner raceway guidance, assume that the external load is , and establish the force and moment balance equations of the inner raceway as: , where Z is the number of rolling elements, e j is the j th eccentricity of the

[0094] Furthermore, in step S4, iteratively solve the bearing quasi-dynamic load force balance equation, and calculate the bearing heat generation according to the iterative solution results, including:

[0095] S41. The bearing quasi-dynamic load force balance equation can be iteratively solved by the improved Newton-Raphson method. Among them, at the initial calculation, the displacement value, oil film thickness, and slice average velocity can be given an initial value by quasi-static analysis. When solving, first give the initial oil film thickness between the rolling elements and the raceways, solve the quasi-dynamic load force balance equation (i.e., the force balance equation), and then iteratively solve the quasi-dynamic velocity force balance equation (i.e., the moment balance equation). The coupled iterative variable is the oil film thickness between the rolling elements and the raceways. After the same solution, each value in the equation can be obtained.

[0096] S42. Calculate the bearing heat generation through the iterative solution results. The bearing heat generation mainly consists of the following parts: a) The frictional heat generation between the rolling elements and the inner and outer raceways is and , where is the driving force of the i-th slice of the j-th rolling element on the inner raceway, is the j th iThe sliding speed of a slice and the inner ring surface is the j th rolling element's i sliding speed between the th slice and the outer ring surface; b) The frictional heat generation between the rolling element and the cage pocket is , where f rcj is the frictional force between the rolling element and the cage pocket; c) The frictional heat generation between the cage guiding surface and the ring rib , ω m is the cage angular velocity, M cx is the moment of the cage about the x-axis, , Z is the number of rolling elements, is the j th rolling element's common angular velocity; d) The heat generated by the viscous damping when the rolling element moves , where F dj is the viscous resistance.

[0097] Furthermore, in the above step S5, according to the bearing high-temperature simulation test results, the bearing thermal boundary conditions are constructed, the heat generation of the bearing is allocated through the heat generation mechanism, the contact position thermal resistance of the test bearing is calculated under the lubricating oil lubrication condition, and the bearing thermal equilibrium equation is established through the bearing heat generation allocation result and the contact position thermal resistance, including:

[0098] S51. Conduct a high-temperature simulation test on the test bearing to obtain the bearing high-temperature simulation test results including the oil supply temperature, the bearing outer ring temperature, and the bearing chamber temperature;

[0099] S52. Take the bearing high-temperature simulation test results as the thermal boundary conditions, and conduct heat generation allocation according to the bearing heat generation, the bearing heat generation position, and the heat transfer ratio;

[0100] S53. Obtain the contact position thermal resistance where the lubricating oil flows through by the thermal network method under the lubricating oil lubrication condition, and establish the bearing thermal equilibrium equation through the heat generation allocation result and the contact position thermal resistance.

[0101] Even further, in the above step S5, the temperature rise of each part on the test bearing is obtained by iterative solution of the bearing thermal equilibrium equation, including:

[0102] Iteratively solve the bearing thermal equilibrium equation by the Gaussian elimination method and the successive over-relaxation method until the convergence accuracy of the current iteration result and the previous iteration result is less than the threshold, and output the temperature rise of each part on the test bearing.

[0103] The above steps S51 to S53 specifically include the following processes:

[0104] The thermal network method is used to calculate the bearing temperature distribution, and a thermal network model of the aviation test bearing as shown in Figure 5 is established. The definitions of each node in the thermal network model are shown in Table 1 below. For the aviation test bearing with under-ring oil supply under high-speed conditions, part of the heat generated by viscous friction is carried away by the lubricating oil, and the other part is transmitted to the surface of the rolling element. Therefore, it can be assumed that λ is the ratio of lubricating oil heat conduction to heat convection, and the value of λ is generally 0.05 - 0.1. H f is the heat generated by viscous friction of the lubricating oil. H f = H rc + H ci + H d . The heat generated by friction between the rolling element and the inner ring H 2 is applied to node 3, the heat generated by friction between the rolling element and the outer ring H 1 is applied to node 5, and part of the heat generated by viscous friction of the lubricating oil, λ H f is applied to node 4, and the other part of the heat generated by viscous friction of the lubricating oil, (1 - λ) H f is applied to node 12.

[0105] Table 1: Definitions of each node in the thermal network model of the aviation test bearing

[0106]

[0107] Through the generalized Ohm's law, the bearing thermal resistance equation can be established as follows: , where the heat flux in the formula is the heat generation. In addition, during under-ring lubrication, the lubricating oil cools the bearing inner ring, rolling element and cage in sequence, and finally flows to the bearing outer ring through the gap between the rolling element and the cage by centrifugal action. To simulate the influence of the sequence of lubricating oil cooling on the bearing temperature distribution, the lubricating oil flow process is divided into 5 nodes (i.e., node 10 - node 14), then there is: , where R 10-11 , R 11-12 , R 12-13 , R 13-14 , R 14-10 are the thermal resistances between node 10 and node 11, between node 11 and node 12, between node 12 and node 13, between node 13 and node 14, and between node 14 and node 10 in sequence, and H fHeat is generated for the bearing. Thus, the node that undergoes heat convection with the inner ring of the bearing is Node 11, the node that undergoes heat convection with the rolling elements and cage of the bearing is Node 12, and the node that undergoes heat convection with the outer ring of the bearing is Node 13.

[0108] The heat exchange of each node in the test bearing mainly occurs through heat conduction and heat convection. According to the structural characteristics of the bearing, the thermal resistance types of each node of the bearing are determined as shown in Table 2 below:

[0109] Table 2: Thermal Resistance Types of Aviation Test Bearings

[0110]

[0111] According to the first law of thermodynamics, the sum of the heat fluxes flowing through each node is equal to 0, so it can be considered that: , where H g is the heat source, Q d is the heat flux through heat conduction, Q v is the heat flux through heat convection.

[0112] To facilitate the establishment of the temperature equation, assume that the heat transfer coefficient S is the reciprocal of the thermal resistance. Thus, for nodes that do not actually have a heat exchange relationship, it is considered that their thermal resistance is infinite, that is, the heat transfer coefficient is 0. Finally, the bearing heat balance equation can be expressed as:

[0113] , where is the temperature of node , is the temperature of node , is the heat transfer coefficient between node and node , and M is the total number of nodes.

[0114] Among them, the temperatures of Node 1, Node 10, and Node 15 can all be measured through experiments and used as the boundary conditions of the heat balance equation. The Gauss elimination method is used to solve the bearing heat balance equation. During iterative calculation, the bearing temperature k obtained in the th step is compared with the bearing temperature k- obtained in the 1st step. If the relative error is less than the convergence accuracy , then the temperatures of each node of the bearing are output and displayed in real time on the monitor. Otherwise, the over-relaxation iteration method is used to iterate the bearing temperature, and the above steps S1~S4 are repeated until convergence.

[0115] To illustrate the effectiveness of the above method of the present invention, a certain type of aviation cylindrical bearing is taken as an example for illustration. The structural parameters of the aviation cylindrical bearing are shown in Table 3 below:

[0116] Table 3: Main parameters of a certain type of aviation cylindrical bearing

[0117]

[0118] First, according to the temperature results of the bearing outer ring measured in the experiment, the initial temperature values of each part of the bearing are given as the temperature of the bearing outer ring, that is , a bearing coordinate system is established, as shown in Figure 3 . The j rolling element is divided into N slices along the length direction. The working clearance of the bearing at the current temperature is calculated in turn according to step S1; the load-displacement relationship between the rolling element load and the inner and outer rings is analyzed according to steps S2 and S3, the average speed and sliding speed between the rolling element and the inner and outer rings are analyzed, the friction force and friction torque between the bearing contact pairs are analyzed, and a force balance equation set for the rolling element, cage and inner ring is established; the bearing frictional heat generation is calculated according to step S4; according to steps S5 and Figure 5 , the temperature rise of each node in the aviation cylindrical bearing is calculated by iterative calculation according to the thermal network node model shown in Figure 6 , that is, referring to the heat transfer coefficient matrix shown in

[0119] Based on the same inventive concept, an aviation bearing temperature rise prediction system based on a high-temperature test device is also provided in the embodiments of the present invention, as described in the following embodiments. Since the principle of solving problems by the aviation bearing temperature rise prediction system is similar to that of the aviation bearing temperature rise prediction method shown in the above embodiments, the implementation of this system can refer to the implementation of the above aviation bearing temperature rise prediction method, and the repeated parts will not be described again.

[0120] Figure 7 FIG. is a structural block diagram of an aviation bearing temperature rise prediction system based on a high-temperature test device disclosed in the embodiments of the present invention. The aviation bearing temperature rise prediction system includes a bearing high-temperature simulation test device 701, a working clearance calculation module 702, a first construction module 703, a viscous resistance calculation module 704, a second construction module 705, a bearing heat generation acquisition module 706 and a temperature rise calculation module 707. The following describes this structure.

[0121] Among them, the bearing high-temperature simulation test device 701 is used to perform a high-temperature simulation test on the test bearing. Specifically, refer to Figure 8As shown in the figure, the bearing high-temperature simulation test device 701 supplies lubricating oil to the test bearing 70 and the oil retaining nut 80 in a way of under-ring oil supply, seals the bearing cavity with a graphite seal 40, heats the test bearing by electric heating, installs 4 temperature measurement probes inside the electric heater 90, leads the probe wires out from the first lead joint 20 and the second lead joint 30, and adjusts the temperature change rules of the heater and the bearing support 10 through the heat insulation cover plate 100 and the control system 110 to keep the temperature of the bearing periphery relatively stable, so as to simulate the high-temperature working environment of the aviation bearing. To prevent oil mist from entering the electric heater 90, an integrated design is carried out for the bearing outer ring compression nut and the oil retaining device, and a high-temperature sealing rubber ring is added between the heat insulation cover plate and the bearing support. The lubricating oil is provided to the rotor assembly 50 through the oil supply nozzle 60, and then the oil supply to the test bearing 70 is realized.

[0122] The working clearance calculation module 702 is used to obtain the working clearance of the test bearing according to the temperature of the bearing outer ring through thermodynamic theory. Specifically, the working clearance calculation module 702 calculates the working clearance of the test bearing through the above steps S11 to S13.

[0123] The first construction module 703 is used to construct the contact load-deformation relationship and the contact load-driving force relationship. The viscous resistance calculation module 704 is used to calculate the viscous resistance borne by the rolling elements according to the angular velocity of the rolling element common rotation and the density of the oil-gas mixture; the second construction module 705 is used to construct the bearing pseudo-dynamic load force balance equation of thermal-fluid-solid coupling. Specifically, the first construction module 703, the viscous resistance calculation module 704 and the second construction module 705 are used to implement the methods of the above steps S22 to S24 and steps S31 to S34.

[0124] The bearing heat generation acquisition module 706 is used to iteratively solve the bearing pseudo-dynamic load force balance equation and calculate the bearing heat generation according to the iterative solution result. Specifically, the bearing heat generation acquisition module 706 is used to calculate the bearing heat generation through steps S41 and S42.

[0125] The temperature rise calculation module 707 is used to construct the bearing thermal boundary conditions according to the bearing high-temperature simulation test results, distribute the bearing heat generation through the heat generation mechanism, calculate the contact position thermal resistance of the test bearing under the lubricating oil condition, establish the bearing heat balance equation through the bearing heat generation distribution result and the contact position thermal resistance, and iteratively solve the bearing heat balance equation to obtain the temperature rise of each part of the bearing. Specifically, the temperature rise calculation module 707 is used to calculate the temperature rise of each part of the test bearing, that is, the temperature rise of each node, through step S5.

[0126] The method of the present invention simulates the high-temperature working state of an aviation bearing, considers the influence of thermal conditions during the bearing operation on the bearing clearance, load distribution, speed distribution, and lubrication characteristics, and proposes a bearing temperature rise prediction method based on the thermal-fluid-solid coupling effect according to the heat distribution law and heat exchange law inside the bearing. Based on this method, rapid iterative optimization of the aviation bearing structure can be achieved, and a more accurate theoretical basis can be provided for the selection of the fit between the bearing and the shaft and the bearing housing, realizing the temperature rise test assessment of the aviation bearing under high-temperature environments. This method has the following advantages:

[0127] 1) The test simulation device can simulate the high-temperature working environment of an aviation bearing that is close to the actual situation. It uses the electric heating method to directly heat the temperature of the bearing periphery, with a fast heating speed and high temperature control accuracy, which is convenient for the test to be realized. The test results are as Figure 2 shown, providing an accurate thermal boundary for the temperature field analysis of the aviation bearing under high-temperature conditions;

[0128] 2) This method considers the influence of thermal-mechanical conditions on the bearing load-carrying characteristics and the influence of the lubrication state of each contact pair on the bearing motion characteristics. Combining the heat distribution law and heat exchange law inside the aviation bearing, more accurate bearing heat generation and temperature rise under thermal-fluid-solid coupling conditions are obtained. The bearing temperature distribution can be quickly and accurately obtained during the bearing structure optimization design, providing a more accurate and reasonable basis for the selection of bearing fit parameters and external oil supply parameters;

[0129] 2) This method is easy to be realized in a process flow and is compiled into a modular calculation program. Combining with the results of the bearing high-temperature simulation test, the real-time temperature rise prediction of the aviation bearing under high-temperature environments can be achieved, providing support for the temperature rise test assessment of the bearing under high-temperature environments outside the engine whole-machine test and reducing the test cost.

[0130] In this embodiment, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned arbitrary aviation bearing temperature rise prediction method based on a high-temperature test device is realized. Specifically, this computer device can be a computer terminal, a server, or a similar computing device.

[0131] In this embodiment, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program for executing any of the above-mentioned aviation bearing temperature rise prediction methods based on a high-temperature test device. Specifically, the computer-readable storage medium includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassette tapes, magnetic disk storage, or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media do not include transitory computer-readable media, such as modulated data signals and carrier waves.

[0132] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the embodiments of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Optionally, they can be implemented by program codes executable by the computing device. Thus, they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order than here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. In this way, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0133] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for predicting temperature rise of aviation bearings based on a high temperature test device, characterized in that: include: The test bearing is heated to collect the temperature of the outer ring of the bearing, and the temperature of the outer ring of the bearing is used as the initial working temperature of each part of the bearing. The working clearance of the test bearing is obtained by using the temperature of the outer ring of the bearing, the structural parameters and the material parameters of the test bearing through the theory of thermodynamics; A contact load-deformation relationship between the rolling element and the raceway of the ferrule is established according to the bearing coordinate system, the working clearance and the oil film thickness, a contact load-drag force relationship between the rolling element and the raceway of the ferrule is established under a given bearing inner ring speed condition, and the viscous resistance borne by the rolling element is calculated according to the rolling element's revolution angular velocity and the density of the oil-gas mixture; According to the contact load-deformation relationship, the contact load-drag force relationship, the viscous resistance, the force and moment between the rolling element and the cage pocket, the force and moment between the cage and the guide ring, and the inertia force and moment of the rolling element, a thermal-fluid-solid coupled bearing pseudo-dynamic load force balance equation is constructed; Iteratively solving the pseudo-dynamic load force balance equation of the bearing, and calculating the heat generation of the bearing according to the iterative solution result; The bearing thermal boundary conditions are constructed according to the results of the high-temperature simulation test of the bearing, the heat generated by the bearing is distributed through the heat generation mechanism, the thermal resistance at the contact position of the test bearing is calculated under the condition of lubricating oil lubrication, the bearing thermal balance equation is established through the bearing heat distribution results and the contact position thermal resistance, and the bearing thermal balance equation is iteratively solved to obtain the temperature rise of each part of the bearing.

2. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: The test bearing is heated to collect the bearing outer ring temperature, the bearing outer ring temperature is used as the initial working temperature of each part of the bearing, and the working clearance of the test bearing is obtained by using the bearing outer ring temperature, the structural parameters and material parameters of the test bearing through the thermodynamic theory, including: The test bearing is heated to collect the temperature of the outer ring of the bearing, and the temperature of the outer ring of the bearing is used as the initial working temperature of the rotating shaft, inner ring, rolling element, outer ring and bearing seat in the test bearing; According to thermodynamic theory, the thermal expansion coefficient, the diameter of the parts, the ambient temperature and the initial working temperature are used to calculate the thermal expansion of the inner ring, the rolling element and the outer ring respectively, and the clearance reduction under the temperature condition is calculated according to the thermal expansion; The working clearance of the test bearing is calculated based on the initial bearing clearance, the clearance reduction under the speed condition, the clearance reduction under the matching condition and the clearance reduction under the temperature condition.

3. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: The contact load-deformation relationship between the rolling element and the ring raceway is constructed based on the bearing coordinate system, the working clearance, the load and the oil film thickness, including: Establishing the bearing coordinate system, the bearing coordinate system includes an inertial coordinate system with the center of the outer ring of the test bearing as the origin, an inner ring coordinate system with the center of the inner ring as the origin, and an azimuth coordinate system with the center of each rolling element as the origin; Dividing each rolling element into a plurality of slices along the length direction of the rolling element by a slicing method, and establishing the relationship between the oil film thickness and the deformation between the slice and the raceway of the ring according to the working clearance and the oil film thickness; The average slice speed and the slice sliding speed of the slice and the ring raceway are calculated according to the inertial coordinate system, the inner ring coordinate system and the azimuth coordinate system by using the angular velocity of the ring, the distance between the slice and the ring, the orbital angular velocity of the rolling body and the rotational angular velocity of the rolling body, and the relationship between the oil film thickness and the contact load between the slice and the ring raceway is established according to the average slice speed through the line contact elastohydrodynamic lubrication theory; Through the relationship between the oil film thickness and the deformation and the relationship between the oil film thickness and the contact load, a contact load-deformation relationship between the rolling element and the ring raceway is constructed according to the Hertz contact theory.

4. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 3 is characterized in that: The expression of the relationship between the oil film thickness and deformation is: ,in, For the j Rolling element i On a slice The distance between point φ and point P on the ferrule surface, For the j The deformation between the i-th slice of the rolling element and the ring, is the deformation caused by the rolling element convexity on the i-th slice, is the deviation angle of the bearing inner ring axis relative to the bearing outer ring axis, is the bearing angular position, is the oil film thickness between the ith slice of the jth rolling element and the ring, i is the slice number representing the ith slice, w is the slice thickness, P d It is the working clearance of the bearing; The expression of the relationship between the oil film thickness and the contact load is: ,in, For the j Rolling element i The average speed of the slices and the ring, is the equivalent elastic modulus of the rolling element and the outer ring, is the equivalent radius of curvature of the rolling element and the ring, is the oil viscosity, is the viscosity-pressure coefficient, Q ji For the j Rolling element i The contact load between the slice and the ring, L r is the rolling element length, is the oil film correction factor considering thermal effects.

5. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: The expression of the contact load-drag force relationship is: ,in, is the drag force between the ith slice and the ring in the jth rolling element, Q ji is the contact load of the i-th slice in the j-th rolling element, is the friction coefficient between the rolling element and the raceway of the ferrule.

6. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: The formula for calculating the viscous resistance of the rolling element based on the rolling element's orbital angular velocity and the density of the oil-gas mixture is: , where F dj is the viscous resistance, D m is the bearing pitch diameter, ρ ef is the density of oil-gas mixture, C D is the damping coefficient, D w is the rolling element diameter, is the rolling body revolution angular velocity of the jth rolling body.

7. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: According to the contact load-deformation relationship, the contact load-drag force relationship, the viscous resistance, the force and moment between the rolling element and the cage pocket, the force and moment between the cage and the guide ring, and the inertia force and moment of the rolling element, a thermal-fluid-solid coupled bearing pseudo-dynamic load force balance equation is constructed, including: According to the long sliding bearing model, the force and torque between the rolling element and the cage pocket are obtained; according to the short sliding bearing model, the force and torque between the cage and the guide ring are obtained; and according to theoretical mechanics, the rolling element inertia force and torque when the test bearing rotates are obtained; According to the force and moment between the rolling element and the cage pocket, the inertia force and moment of the rolling element, the contact load-deformation relationship and the viscous resistance, a force balance equation and a moment balance equation of the rolling element under thermal-fluid-solid coupling are established; In steady-state operation, the cage rotation speed is taken as a constant value as a constraint condition, and according to the force and torque between the cage and the guide ring, a force balance equation and a torque balance equation of the cage with thermal-fluid-solid coupling are established; Under given external load conditions, according to the contact load-deformation relationship and the contact load-drag force relationship, the force balance equation and torque balance equation of the inner ring of the thermal-fluid-solid coupling are established to complete the construction of the pseudo-dynamic load force balance equation of the bearing.

8. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 1, characterized in that: According to the results of the high-temperature simulation test of the bearing, the thermal boundary conditions of the bearing are constructed, the heat generated by the bearing is distributed through the heat generation mechanism, the thermal resistance at the contact position of the test bearing is calculated under the lubricating oil lubrication condition, and the thermal balance equation of the bearing is established through the heat distribution results of the bearing and the thermal resistance at the contact position, including: Performing a high temperature simulation test on the test bearing to obtain the bearing high temperature simulation test results including the oil supply temperature, the bearing outer ring temperature and the bearing cavity temperature; The high temperature simulation test results of the bearing are used as thermal boundary conditions, and heat generation distribution is performed according to the heat generation of the bearing, the heat generation position of the bearing, and the heat transfer ratio; Under lubricating oil conditions, the thermal resistance of the contact position through which the lubricating oil flows is obtained by the thermal network method, and the bearing thermal balance equation is established by the heat distribution result and the thermal resistance of the contact position.

9. The method for predicting temperature rise of aviation bearings based on a high temperature test device according to claim 8, characterized in that: The bearing heat balance equation is iteratively solved to obtain the temperature rise of each part of the test bearing, including: The bearing thermal balance equation is iteratively solved by Gaussian elimination method and super relaxation iteration method until the result of this iteration is The result of the previous iteration The convergence accuracy of is less than a threshold value, and the temperature rise of each part of the test bearing is output.

10. An aviation bearing temperature rise prediction system based on a high temperature test device, characterized in that: include: A bearing high temperature simulation test device, wherein the bearing high temperature simulation test device is used to perform a high temperature simulation test on a test bearing; A working clearance calculation module, which is used to obtain the working clearance of the test bearing through thermodynamic theory according to the temperature of the outer ring of the bearing; A first building module, the first building module is used to build a contact load-deformation relationship and a contact load-drag force relationship; A viscous resistance calculation module, which is used to calculate the viscous resistance borne by the rolling body according to the rolling body's revolution angular velocity and the density of the oil-gas mixture; A second building block, the second building block is used to build a thermal-fluid-solid coupled bearing pseudo-dynamic load force balance equation; A bearing heat generation acquisition module, the bearing heat generation acquisition module is used to iteratively solve the bearing pseudo-dynamic load force balance equation and calculate the bearing heat generation according to the iterative solution result; A temperature rise calculation module is used to construct a bearing thermal boundary condition according to the bearing high temperature simulation test results, distribute the bearing heat through the heat generation mechanism, calculate the contact position thermal resistance of the test bearing under oil lubrication conditions, establish a bearing thermal balance equation through the bearing heat distribution results and the contact position thermal resistance, and iteratively solve the bearing thermal balance equation to obtain the temperature rise of each part of the bearing.

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