动车组车轮流场数值模拟分析

基于Realizable k-epsilon的分离涡湍流模型,研究在固定地面、滑移地面和轮转兼滑移地面3种情况下,动车组车轮气动性能,对比分析这3种边界条件对车轮数值模拟的影响。研究结果表明：与固定地面情况相比,计算得到的列车总阻力在滑移地面兼车轮转条件下增加了约29.3%,滑移地面条件下增加了约2.76%;轮转兼滑移地面情况下得到的气动升力与力矩绝对值均大于其他2种情况下的;滑移地面和固定地面条件下,车轮周围流场结构相似,尾涡主要从车轮两侧分离并向后发展、脱落,2种情况下车轮表面和后部区域压力分布规律相似;轮转边界条件下,车轮旋转带动车轮后部气流上扬,流速加快,该条件下车轮周围涡量主要从顶部分离并向后发展,影响了车轮表面和后部区域压力分布。

Numerical simulation of flow field around wheel of EMU

The aerodynamic performance of wheel of high-speed train was investigated under stationary ground,moving ground and moving ground with rotating wheel conditions by using DES based on Realizable k-epsilon equation. The influence of different ground boundary conditions on the result of numerical simulation was analyzed. The results shows that the total drag force calculated under the moving ground and rotating wheel conditions increases 29. 3%,and under moving ground condition increases 2. 76%,comparing with that under stationary ground condition. And the absolute value of total lift force and moment are bigger than other situations.The flow field structures under stationary condition around the wheel are similar to that in moving wall condition,which leads to the pressure distribution of the wheel and behind the wheel similar. Shed wake vortexes are produced mainly in the two side of the wheel and progress backward. While the flow field structure changes under the rotating wheel condition where airflow behind the wheel rises and flows rapidly with the wheel rotating. The vortexes are mainly separated from the top of wheel and progress backward,which influences the pressure distribution of the wheel and behind the wheel.