对流换热系数对轮轨滑动接触特性的影响分析
Influence analysis of coefficients of convective heat transfer on the characteristic of wheel/rail sliding contact

建立模拟轮轨滑动接触的热弹塑性有限元三维模型，以2种滑动速度为例研究机械荷载作用下对流换热系数对接触区的温度、接触斑的大小以及最大等效应力等轮轨接触特性的影响。研究结果表明：各研究工况下轮轨滑动摩擦热均能使接触区域达到相变温度；轮轨接触区的温度、接触斑的大小以及等效应力在有、无对流换热系数2种情况下差异显著，故对流换热系数在对轮轨滑动状态进行数值分析时不应忽略；对流换热系数的变化对接触特性的影响与滑动速度有关，建议2 m/s及以上速度的研究中对流换热系数可以取为定值，但在1 m/s及以下速度的研究中，对流换热系数的准确选取需进行深入研究。
A three-dimensional thermal elastic-plastic finite element model was established to simulate the sliding contact of wheal-rail. Taking two kinds of speed for example, the influence of convective heat transfer coefficient on the characteristics of wheel/rail sliding contact under mechanical loads was studied, which include the temperature of the contact area, the size of the contact spot and the maximum equivalent stress. The results show that: slip friction heat of every research condition can achieve the phase transition temperature of wheel/rail materials. The existence of the convective heat transfer coefficient has obvious influence on the temperature of the contact zone, the size of the contact spot and the equivalent stress, therefore, this coefficient should not be ignored in the numerical analysis of wheel/rail sliding state. The influence of change of coefficients of convective heat transfer on the contact characteristics is related to sliding speed. Coefficients of convective heat transfer can be taken as a constant value in the study of more than 2 m/s, while the choice of coefficient should be researched further in the study of less than 1m/s