Analysis And Numerical Simulation Of Bearing Temperature Field Of High-Speed Train

Bearing is the significant part to make sure the safe running of high-speed train.And the complex and harsh internal environment severely affect the performance of bearing,will lead to corrosion,spalling and cracks,bringing great danger to the train.At present,the train applies sensors to monitor temperature inside the bearing,and when the temperature reach threshold set before,the alarms sound.This method is hard to measure temperature and this pre-alarm method cannot use the complete performance of bearings.Therefore,it is of great scientific significance and engineering application value to analyze the thermal process of bearing and obtain its internal temperature field distribution by a relatively accurate and concise method.The research methods of bearing temperature field distribution characteristics generally include:finite element analysis method depending on model boundary conditions and mesh number,analytical methods of mathematical formula based on heat transfer or thermal network method based on thermal resistance principle.Compared with the numerical method,the analytical method is better under certain mathematical model because of its directness,accuracy and programmability.In the analytical solution of the bearing model,some research schemes use the analytical method of integral transformation,while the Green’s function method is hardly used.This article is mainly absorbed in the analytical solution for solving the temperature of bearing of high-speed train and compare the deep groove ball bearings to verify the reliability of the Green’s function.The related researches are as follows:Propose an optimized heat source distribution model.In the existing heat source distribution results,it is impossible to comprehensively consider the distribution of relatively moving heat sources and static heat sources,resulting in the static heat source distribution models cannot be used in mobile heat sources.In this paper,an adjustable factor is added to realize the distribution of heat sources under different working situations,which ensures the accuracy and reduces the operation cost,especially is good for the heat distribution in bearing.Study the optimal load form under steady-state thermal analysis by load different heat forms.Propose the mathematical model based on the Green’s function to study the temperature field of bearing.The advantage of Green’s function method lies in the superposition of the point heat source solution.Compared with the methods of variable separation and integral transformation,it is more flexible and suitable for any heat source with any position,time and intensity.According to the Green’s function equation proposed,this article uses MATLAB programming to obtain the result of the mathematical equation.And the accuracy of Green’s function relies on the number of Bessel function and eigenvalues under the non-uniform heat source.The comparative study of the finite element simulation based on ANSYS and COMSOL and the analytical results based on Green function is carried out.Ansys Workbench is used to simulate the temperature field characteristics of double row cylindrical roller bearing,and COMSOL is used to simulate the temperature field characteristics of deep groove ball bearing.The comparison between the two numerical simulation methods and Green function method shows that the accuracy of Green function analytical solution is higher and the compute speed is faster.And the high temperature occurs at the contact of roller and raceway and the highest is on the roller.The bearing with rib has the lower overall maximum temperature,and the highest temperature occurs beside the rib.This is consistent with the results of the two numerical simulations,which further verifies the feasibility of the Green’s function.The characteristics of friction heat production and temperature variation under different loads,rotational speeds and viscosities are studied respectively in this paper,and two key nodes that affect the results are obtained,which are rotational speed of 1000 rad/min and load of 170 kN.When the speed and load are greater than the nodes,the temperature change rate of the roller and the inner and outer raceways decrease,the temperature changes linearly before and after the node;The higher the viscosity or the higher the speed,the higher the bearing temperature,Therefore,when the bearing speed is high,use low-viscosity lubricant to control the temperature is better and temperature is sensitive to the speed;According to the result of Green’s function method,the highest temperature of other part in bearing can be directly obtained under certain condition.