A method for predicting temperature field of thrust ball bearing based on oil-gas two-phase flow heat exchange

Abstract

This invention discloses a method for predicting the temperature field of a thrust ball bearing based on two-phase oil-gas flow heat transfer. This method addresses the problems of existing bearing temperature field prediction methods failing to reflect the characteristics of the two-phase oil-gas flow within the thrust ball bearing, failing to consider differences between different bearing components, and failing to account for the influence of different oil supply conditions, resulting in low accuracy of the obtained bearing thermal analysis results. This invention calculates the heat generation and proportion of each component in the thrust ball bearing. Motion parameters of each component are selected, and then, combined with a three-dimensional flow domain model of the thrust ball bearing and the rotational speed of the inner ring, the motion of each component is simulated using FLUENT fluid analysis software to obtain the oil-gas ratio of the thrust ball bearing. The proportion of heat generation of each component is corrected based on the oil-gas ratio, and then the heat generation of each component is applied to each component to obtain the convective heat transfer coefficient of each component. The heat generation and convective heat transfer coefficient of each component are then applied to each component, and the temperature field of the thrust ball bearing is predicted using a steady-state thermal analysis method.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more specifically to a method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas. Background Technology

[0002] Thrust ball bearings are the main supporting components of aero-engine rotor systems, bearing axial and radial loads. With the development of aero-engines, thrust ball bearings need to have characteristics such as high temperature resistance and high reliability. Lubrication and cooling of thrust ball bearings are the core means to achieve temperature control performance. Therefore, the ability to accurately and precisely assess the temperature of thrust ball bearings is crucial to their design.

[0003] Regarding heat transfer between bearings and lubricating oil, current calculations of bearing convective heat transfer coefficients mainly rely on empirical formulas from scholars such as Gupta and Crecelius, simplifying bearings into physical models like cylinders and flat plates in heat transfer. While this method has been widely used for bearing temperature field prediction, it fails to reflect the characteristics of two-phase flow of oil and gas within aero-engine thrust ball bearings. It lacks theoretical basis and cannot account for differences between different bearing components, such as the inner and outer rings, cage, and rolling elements, nor can it consider the influence of different oil supply conditions. This leads to significant deviations in bearing thermal analysis results. Therefore, to accurately obtain the convective heat transfer coefficient within a bearing, it is necessary to combine this method with two-phase flow heat transfer analysis of oil and gas within the bearing. Summary of the Invention

[0004] To address the problems of existing bearing temperature field prediction methods failing to reflect the characteristics of two-phase oil-gas flow inside thrust ball bearings, failing to consider differences between different bearing components, and failing to account for the influence of different oil supply conditions, resulting in low accuracy of the obtained bearing thermal analysis results, this invention proposes a thrust ball bearing temperature field prediction method based on two-phase oil-gas flow heat transfer.

[0005] The technical solution adopted in this invention is:

[0006] It includes the following steps:

[0007] S1. Based on the six degrees of freedom of each part of the thrust ball bearing and the rotational speed of the inner ring or the outer ring, calculate the motion parameters of the thrust ball bearing under working conditions using the complete dynamic analysis method. Generate a motion law dataset, geometric parameter dataset, and lubrication parameter dataset containing all parts based on the motion parameters and each part of the thrust ball bearing.

[0008] The components include an inner ring, an outer ring, a cage, and rolling elements. The motion law includes the rotational speed of each component. The geometric parameters include the dimensions of each component. The lubrication parameters include the type of lubricating oil, the flow rate, the density, and the viscosity of the lubricating oil for each component.

[0009] S2. Based on the motion law dataset and lubrication parameter dataset, calculate the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage, the viscous friction loss of the lubricating oil, and the total heat generation, and obtain the proportional distribution of the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage, and the viscous friction loss of the lubricating oil in the total heat generation.

[0010] S3. Construct a three-dimensional fluid domain model of the thrust ball bearing based on the geometric parameter dataset and the lubrication parameter dataset, and select motion parameters from the motion law dataset. Based on the three-dimensional fluid domain model of the thrust ball bearing, the selected motion parameters and the rotational speed of the inner ring, use FLUENT fluid analysis software to simulate the motion of the inner ring, outer ring, cage and rolling elements of the thrust ball bearing, and obtain the oil-air ratio in the inner cavity of the thrust ball bearing. The oil-air ratio includes the volume fraction of lubricating oil and air on the surface of the rolling elements and the volume fraction of lubricating oil and air in the guide clearance of the cage.

[0011] S4. Based on the oil-air ratio, correct the viscous friction loss of the lubricating oil, the total heat generation, and the heat generation of the inner ring, outer ring, and cage, as well as the proportion of the corrected viscous friction loss of the lubricating oil in the total heat generation.

[0012] S5. Based on S4, FLUENT fluid analysis software is used to apply the heat generated by the inner ring to the inner ring raceway surface and obtain the convective heat transfer coefficient of the inner ring raceway surface, apply the heat generated by the outer ring to the outer ring raceway surface and obtain the convective heat transfer coefficient of the outer ring raceway surface, apply the heat generated by the cage to the cage guide surface and obtain the convective heat transfer coefficient of the cage guide surface, and apply the viscous friction loss of the lubricating oil to the rolling element surface and obtain the convective heat transfer coefficient of the rolling element surface.

[0013] S6. Establish a solid domain model of the thrust ball bearing using the finite element method;

[0014] Based on the solid domain model, the heat generated by the inner ring and the convective heat transfer coefficient of the inner ring raceway surface are applied to the inner ring raceway surface; the heat generated by the outer ring and the convective heat transfer coefficient of the outer ring raceway surface are applied to the outer ring raceway surface; the heat generated by the cage and the convective heat transfer coefficient of the cage guide surface are applied to the cage guide surface; and the viscous friction loss of the lubricating oil and the convective heat transfer coefficient of the rolling element surface are applied to the rolling element surface. The resulting thrust ball bearing is then analyzed using steady-state thermal analysis to obtain the predicted temperature field of the thrust ball bearing.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention calculates the heat generation of each component of a thrust ball bearing, the viscous friction loss of the lubricating oil, the changes in the lubricating oil flow domain and the oil-air ratio within the bearing cavity, and uses the oil-air ratio to correct for the viscous friction loss of the lubricating oil. Based on the heat generation of each component, the convective heat transfer coefficient of each component is calculated, and based on the viscous friction loss of the lubricating oil, the convective heat transfer coefficient of the rolling element surface is calculated. The heat generation and convective heat transfer coefficients are then applied sequentially to corresponding positions on the thrust ball bearing, and the temperature field of the thrust ball bearing is obtained using steady-state thermal analysis. This invention utilizes the two-phase flow characteristics of oil and gas inside the thrust ball bearing, combined with the differences in the positions of the components and the distribution characteristics of the lubricating oil, to calculate the temperature field of the thrust ball bearing. This not only considers the flow law of the lubricating oil but also more accurately obtains the bearing heat transfer boundary, thus yielding a more accurate temperature field for the thrust ball bearing and providing a reference for design. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the oil-air ratio in the inner ring of a thrust ball bearing;

[0018] Figure 2 This is a schematic diagram of the convective heat transfer coefficient of the inner ring of a thrust ball bearing.

[0019] Figure 3 This is a graph showing the variation of the outward heat transfer coefficient of each working surface of the thrust ball bearing at different rotational speeds.

[0020] Figure 4 This is a diagram showing the heat distribution ratio among the various components of a thrust ball bearing;

[0021] Figure 5 This is a schematic diagram of the temperature field of a thrust ball bearing; Detailed Implementation

[0022] Specific implementation method one: Combining Figures 1-5 This embodiment describes a method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas. The method includes the following steps:

[0023] S1. Based on the six degrees of freedom of each component of the thrust ball bearing in the engine and the rotational speed of either the inner or outer ring, calculate the motion parameters of the thrust ball bearing under combined axial and radial load conditions using a complete dynamic analysis method. Generate a dataset containing motion law data, geometric parameter data, and lubrication parameter data for all components based on the motion parameters and the components of the thrust ball bearing. The components include the inner ring, outer ring, cage, and rolling elements. The motion parameters include the rotational speed of the cage, the revolution speed and rotational speed of the rolling elements, the rotational attitude angle of the rolling elements, and the contact angle between the rolling elements and the raceway. The motion law includes the rotational speed of each component. The geometric parameters include the dimensions of each component. The lubrication parameters include the lubricant type, flow rate, density, and viscosity of each component.

[0024] S2. Based on the motion law dataset and lubrication parameter dataset, calculate the heat generation of the inner ring, the heat generation of the outer ring and the heat generation of the cage according to equation (1), calculate the viscous friction loss of the lubricating oil according to equation (2), take the sum of the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage and the viscous friction loss of the lubricating oil as the total heat generation, and calculate the proportion distribution of the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage and the viscous friction loss of the lubricating oil in the total heat generation.

[0025] (1)

[0026] when To generate heat in the inner circle hour, This refers to the frictional torque between the inner ring and the rolling elements. The rotational speed of the inner ring; when Generate heat for the outer ring hour, This refers to the frictional torque between the outer ring and the rolling elements. For the outer ring's rotational speed; when To maintain the heat generated by the rack hour, To maintain the frictional torque between the cage and the rolling elements, To maintain the rotational speed of the cage.

[0027] (2)

[0028] (3)

[0029] (4)

[0030] (5)

[0031] (6)

[0032] in, This is due to the viscous friction loss of the lubricating oil. For the loss due to drag of rolling elements, For rolling element eddy current loss, To maintain the frame vortex loss, The drag resistance coefficient of the rolling element is... The density of the lubricating oil, Let the linear velocity of the rolling element be the orbital velocity. It represents the area of ​​contact between the lubricating oil and the rolling elements in the direction of oil flow. The eddy drag coefficient of the rolling element is... The angular velocity of the rolling element's rotation. Where is the radius of the rolling element. To maintain the coefficient of friction of the cage, To maintain the vortex drag coefficient, The average velocity of the fluid. To maintain the area of ​​the pocket opening, To maintain the rotation radius of the cage, To maintain the orbital speed, This refers to the total heat generated. Viscous friction loss of lubricating oil refers to the heat generated during bearing operation due to the internal friction of the lubricating oil and the sliding between the rolling elements and the raceway.

[0033] S3. Construct a three-dimensional flow domain model of the thrust ball bearing based on the geometric parameter dataset and lubrication parameter dataset. Then, select some motion parameters from the motion law dataset using the oil-gas two-phase flow analysis method. Next, based on the three-dimensional flow domain model of the thrust ball bearing, the selected motion parameters, and the rotational speed of the inner ring, use FLUENT fluid analysis software to simulate the motion of the inner ring, outer ring, cage, and rolling elements of the thrust ball bearing. This yields the oil-air ratio within the thrust ball bearing cavity. The oil-air ratio includes the volume fraction of lubricating oil and air on the surface of the rolling elements, as well as the volume fraction of lubricating oil and air within the cage guide clearance. Figure 1 As shown. The specific process is as follows:

[0034] S31. Based on the geometric parameter dataset and lubrication parameter dataset, construct a three-dimensional flow domain model of the thrust ball bearing using SolidWorks or NX software.

[0035] S32. Obtain the rotational speed of the inner ring, and select the rotational speed of the cage, the revolution speed of the rolling element, and the rotational attitude angle of the rolling element from the motion law dataset according to the oil-gas two-phase flow analysis method. Take the rotational speed of the cage as the absolute rotational speed of the inner cavity of the thrust ball bearing, and take the rotational speed of the inner ring as the absolute rotational speed of the wall surface, where the wall surface is the interface between the lubricating oil and the inner ring.

[0036] S33. Based on the three-dimensional model of the thrust ball bearing, the rotational speed of the cage, the revolution speed of the rolling elements, the rotational attitude angle of the rolling elements, and the rotational speed of the inner ring, the motion of the inner ring, cage, rolling elements, and outer ring of the thrust ball bearing is simulated using FLUENT fluid analysis software (using a combination of sliding mesh and rotating coordinate system). The changes in the lubricating oil flow domain in the inner cavity of the thrust ball bearing are obtained, and the oil-air ratio is calculated based on the changes in the lubricating oil flow domain, the properties of the lubricating oil, and the rotational speed of the bearing.

[0037] S4. Based on the oil-air ratio, correct the viscous friction loss of the lubricating oil, the total heat generation, and the heat generation of the inner ring, outer ring, and cage, as well as the proportion of the corrected viscous friction loss of the lubricating oil in the total heat generation. The specific process is as follows:

[0038] Calculate the effective density of the lubricating oil on the surface of the rolling element based on the volume fraction of lubricating oil and the volume fraction of air on the rolling element surface:

[0039] (7)

[0040] in, The effective density of the lubricating oil, For the density of lubricating oil, This refers to the volume fraction of the lubricating oil. air density, The air volume fraction is used. Based on the effective density of the lubricating oil on the rolling element surface, the rolling element drag loss is calculated using formula (3). The rolling element whirl loss is calculated using formula (4). .

[0041] Based on the volume fraction of lubricating oil and the volume fraction of air in the cage guide gap, the effective density of the lubricating oil in the cage guide gap is calculated using formula (7). Based on the effective density of the lubricating oil in the cage guide gap, the cage whirl loss is calculated using formula (5). .

[0042] Based on the above calculation of rolling element drag loss vortex loss of rolling elements and cage vortex loss Formula (2) is used to correct the viscous friction loss of lubricating oil. Based on the corrected viscous friction loss of the lubricating oil, the total heat generation is corrected using formula (6), and the proportions of the inner ring heat generation, outer ring heat generation, cage heat generation, and the corrected viscous friction loss of the lubricating oil in the total heat generation are also corrected. Figure 4 As shown.

[0043] S5, such as Figure 1 and Figure 2 As shown. Based on S4, the following processing was performed using FLUENT fluid analysis software (with VOF applied and energy equations enabled):

[0044] The heat generated in the inner ring of a thrust ball bearing is applied to the inner ring raceway surface, thus obtaining the convective heat transfer coefficient of the inner ring raceway surface, such as... Figure 2 As shown. The heat generated by the outer ring is applied to the outer ring raceway surface to obtain the convective heat transfer coefficient of the outer ring raceway surface; the heat generated by the cage is applied to the cage guide surface to obtain the convective heat transfer coefficient of the cage guide surface; the viscous friction loss of the lubricating oil is applied to the rolling element surface to obtain the convective heat transfer coefficient of the rolling element surface. For example... Figure 3 As shown.

[0045] S6. A solid domain model of the thrust ball bearing is established using the finite element method, and the chamfer features of the ineffective working surfaces of the thrust ball bearing are simplified. Based on the solid domain model, the heat generation of the inner ring and the convective heat transfer coefficient of the inner ring raceway are applied to the inner ring raceway surface; the heat generation of the outer ring and the convective heat transfer coefficient of the outer ring raceway surface are applied to the outer ring raceway surface; the heat generation of the cage and the convective heat transfer coefficient of the cage guide surface are applied to the cage guide surface; and the viscous friction loss of the lubricating oil and the convective heat transfer coefficient of the rolling element surface are applied to the rolling element surface. The resulting thrust ball bearing is then analyzed using steady-state thermal analysis to obtain the predicted temperature field of the thrust ball bearing. Figure 5 As shown.

[0046] The thrust ball bearing of this invention is a component of an aero-engine. Based on the motion parameters of the thrust ball bearing under different operating conditions of the aero-engine, the temperature field of the thrust ball bearing is predicted by performing the calculation processes S1 to S6 described above. This invention predicts the temperature field of the thrust ball bearing by considering the heat generation, oil-gas ratio, and convective heat transfer coefficient of each component. It takes into account the two-phase flow characteristics of oil and gas inside the thrust ball bearing and the differences between different positions of the bearing components, thus obtaining the bearing heat transfer boundary and convective heat transfer coefficient more accurately, thereby accurately predicting the temperature field of the thrust ball bearing.

[0047] The above examples of the present invention are merely illustrative of the computational model and process of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas, characterized in that: It includes the following steps: S1. Based on the six degrees of freedom of each part of the thrust ball bearing and the rotational speed of the inner ring or the outer ring, calculate the motion parameters of the thrust ball bearing under working conditions using the complete dynamic analysis method. Generate a motion law dataset, geometric parameter dataset, and lubrication parameter dataset containing all parts based on the motion parameters and each part of the thrust ball bearing. The components include an inner ring, an outer ring, a cage, and rolling elements. The motion law includes the rotational speed of each component. The geometric parameters include the dimensions of each component. The lubrication parameters include the type of lubricating oil, the flow rate, the density, and the viscosity of the lubricating oil for each component. S2. Based on the motion law dataset and lubrication parameter dataset, calculate the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage, the viscous friction loss of the lubricating oil, and the total heat generation, and obtain the proportional distribution of the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage, and the viscous friction loss of the lubricating oil in the total heat generation. S3. Construct a three-dimensional fluid domain model of the thrust ball bearing based on the geometric parameter dataset and the lubrication parameter dataset, and select motion parameters from the motion law dataset. Based on the three-dimensional fluid domain model of the thrust ball bearing, the selected motion parameters and the rotational speed of the inner ring, use FLUENT fluid analysis software to simulate the motion of the inner ring, outer ring, cage and rolling elements of the thrust ball bearing, and obtain the oil-air ratio in the inner cavity of the thrust ball bearing. The oil-air ratio includes the volume fraction of lubricating oil and air on the surface of the rolling elements and the volume fraction of lubricating oil and air in the guide clearance of the cage. S4. Based on the oil-air ratio, correct the viscous friction loss of the lubricating oil, the total heat generation, and the heat generation of the inner ring, outer ring, and cage, as well as the proportion of the corrected viscous friction loss of the lubricating oil in the total heat generation. S5. Based on S4, FLUENT fluid analysis software is used to apply the heat generated by the inner ring to the inner ring raceway surface and obtain the convective heat transfer coefficient of the inner ring raceway surface, apply the heat generated by the outer ring to the outer ring raceway surface and obtain the convective heat transfer coefficient of the outer ring raceway surface, apply the heat generated by the cage to the cage guide surface and obtain the convective heat transfer coefficient of the cage guide surface, and apply the viscous friction loss of the lubricating oil to the rolling element surface and obtain the convective heat transfer coefficient of the rolling element surface. S6. Establish a solid domain model of the thrust ball bearing using the finite element method; Based on the solid domain model, the heat generated by the inner ring and the convective heat transfer coefficient of the inner ring raceway surface are applied to the inner ring raceway surface; the heat generated by the outer ring and the convective heat transfer coefficient of the outer ring raceway surface are applied to the outer ring raceway surface; the heat generated by the cage and the convective heat transfer coefficient of the cage guide surface are applied to the cage guide surface; and the viscous friction loss of the lubricating oil and the convective heat transfer coefficient of the rolling element surface are applied to the rolling element surface. The resulting thrust ball bearing is then analyzed using steady-state thermal analysis to obtain the predicted temperature field of the thrust ball bearing.

2. The method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas as described in claim 1, characterized in that: The motion parameters in S1 include the rotational speed of the cage, the revolution speed and rotational speed of the rolling elements, the rotational attitude angle of the rolling elements, and the contact angle between the rolling elements and the raceway.

3. The method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas as described in claim 2, characterized in that: The specific process of S2 is as follows: （1） when To generate heat in the inner circle hour, This refers to the frictional torque between the inner ring and the rolling elements. The rotational speed of the inner ring; when Generate heat for the outer ring hour, This refers to the frictional torque between the outer ring and the rolling elements. The rotational speed of the outer ring; when To maintain the heat generated by the rack hour, To maintain the frictional torque between the cage and the rolling elements, To maintain the rotational speed of the cage; （2） （3） （4） （5） in, This is due to the viscous friction loss of the lubricating oil. For the loss due to drag of rolling elements, For rolling element eddy current loss, To maintain the frame vortex loss, The drag resistance coefficient of the rolling element is... The density of the lubricating oil, Let the linear velocity of the rolling element be the orbital velocity. It represents the area of ​​contact between the lubricating oil and the rolling elements in the direction of oil flow. The eddy drag coefficient of the rolling element is... The angular velocity of the rolling element's rotation. Where is the radius of the rolling element. To maintain the coefficient of friction of the cage, To maintain the vortex drag coefficient, The average velocity of the fluid. To maintain the area of ​​the pocket opening, To maintain the rotation radius of the cage, To maintain the orbital speed; （6） in, Total heat generated; Based on total heat generation Calculate the proportion of heat generated by the inner ring, outer ring, cage, and viscous friction loss of the lubricating oil in the total heat generated.

4. The method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas as described in claim 3, characterized in that: The specific process of S3 is as follows: S31. Construct a three-dimensional flow domain model of the thrust ball bearing based on the geometric parameter dataset and the lubrication parameter dataset; S32. Obtain the rotational speed of the inner ring, and select the rotational speed of the cage, the revolution speed of the rolling elements, and the rotational attitude angle of the rolling elements from the motion law dataset. Use the rotational speed of the cage as the absolute rotational speed of the inner cavity of the thrust ball bearing, and use the rotational speed of the inner ring as the absolute rotational speed of the interface between the lubricating oil and the inner ring. S33. Based on the three-dimensional model of the thrust ball bearing, the rotational speed of the cage, the revolution speed of the rolling elements, the rotational attitude angle of the rolling elements, and the rotational speed of the inner ring, the motion of the inner ring, outer ring, cage, and rolling elements of the thrust ball bearing is simulated using FLUENT fluid analysis software to obtain the changes in the lubricating oil flow domain in the inner cavity of the thrust ball bearing. The oil-air ratio is calculated based on the changes in the lubricating oil flow domain, the properties of the lubricating oil, and the rotational speed of the bearing.

5. The method for predicting the temperature field of a thrust ball bearing based on two-phase flow heat transfer of oil and gas as described in claim 1, characterized in that: The specific process of S4 is as follows: Calculate the effective density of the lubricating oil on the surface of the rolling element based on the volume fraction of lubricating oil and the volume fraction of air on the rolling element surface: （7） in, The effective density of the lubricating oil, For the density of lubricating oil, This refers to the volume fraction of the lubricating oil. air density, It represents the volume fraction of air. Based on the effective density of the lubricating oil on the surface of the rolling element, the drag loss of the rolling element is calculated using formula (3). The rolling element whirl loss is calculated using formula (4). ; Based on the volume fraction of lubricating oil and the volume fraction of air in the cage guide gap, the effective density of the lubricating oil in the cage guide gap is calculated using formula (7). Based on the effective density of the lubricating oil in the cage guide gap, the cage whirl loss is calculated using formula (5). ; Based on the above calculation of rolling element drag loss vortex loss of rolling elements and cage vortex loss Formula (2) is used to correct the viscous friction loss of lubricating oil. Based on the corrected viscous friction loss of the lubricating oil, the total heat generation is corrected using formula (6), and the proportions of the heat generation of the inner ring, the heat generation of the outer ring, the heat generation of the cage, and the corrected viscous friction loss of the lubricating oil in the total heat generation are also corrected.

Images