不同对流换热系数下轮轨滑动摩擦热的分析

Analysis of the Sliding Friction Heat of Wheel/Rail under Different Coefficients of Convective Heat Transfer

轮轨之间的相对滑动所产生的摩擦热是引起轮轨摩擦损伤的主要因素.对流换热作为轮轨滑动接触中客观存在的自然现象,对流换热系数的大小决定了轮轨与空气间的热量传递,大部分科研工作者在轮轨滑动接触分析中将对流换热系数取为20 W·(m2·K)-1,有的根据实验取为100 W·(m2·K)-1;借助ANSYS有限元软件,对轮轨滑动状态进行三维热弹塑性分析,针对不同的对流换热系数,在指定滑动速度下,分析轮轨接触区的温度场变化.结果表明:对流换热系数的成倍增加,没有引起轮轨接触区温度场的巨大变化,对流换热系数数值的大小变化对轮轨滑动摩擦的接触影响很小,证明对流换热耗散的热量相对于轮轨摩擦产生的热量非常小,对数值模拟的结果影响不大,在轮轨的数值模拟计算中可以将对流换热系数取一个定值.

Sliding frictional heat generated between wheel and rail is a major factor causing the fric-tion injury of wheel/rail.The convective heat transfer is objective existence of natural phenomena in the process of wheel/rail sliding.The number of heat transfer between the wheel/rail and air is determined by the size of the coefficient of convective heat transfer.And the convective heat transfer coefficient is taken to be 20 W/（m^2 ·K）in the analysis of the wheel/rail sliding contact by most researchers.Some researchers take it as 100 W/（m2 · K）based on experiments.The a-nalysis of three dimension thermal elastic-plastic of wheel/rail sliding state is implemented by the finite element software of ANSYS.The temperature field change of wheel-rail contact area in dif-ferent coefficients of convective heat transfer under specified sliding speed is analyzed.The re-sults show that the convective heat transfer coefficient multiplied doesn＆#39;t cause the huge change of temperature field of wheel/rail contact region,and the effect of numerical change of the coefficient of convective heat transfer on wheel/rail sliding friction contact is very small.Research proves that convective heat dissipation of heat is very small relative to the wheel/rail friction heat and has little influence on the result of numerical simulation,so the coefficient of convective heat transfer can be taken as a constant value in the numerical simulation of wheel/rail.