兰新铁路挡沙墙位置对低矮路堑中客车气动性能的影响

Effect of sand control wall's position on aerodynamic performance of passenger train in low cutting along Lanzhou—Xinjiang railway

采用计算流体力学方法对兰新(甘肃兰州—新疆乌鲁木齐)铁路挡沙墙对低矮路堑中客车气动性能的影响进行数值模拟。研究结果表明:低矮路堑无挡沙墙时,列车受到较大的横向力、升力和倾覆力矩作用,当在路堑迎风侧设置距离上边缘一定距离的挡沙墙后,列车气动力明显减小;当距离L=5 m时,迎风线整车阻力、横向力、升力和倾覆力矩分别减少25.0%,88.9%,75.4%和83.6%,背风线整车阻力、横向力、升力和倾覆力矩分别减少44.2%,82.2%,74.4%和76.5%;设置挡沙墙后,随着距离越来越近,车体迎风侧正压区域逐渐变为小负压区域,顶部负压减小,整个车体基本处于小负压环境中,车体整体受力情况明显改善。

Using CFD（computational fluid dynamics） method, numerical simulation of effect of sand control wall＇s position on the aerodynamic performance of a passenger train in low cutting along Lanzhou — Xinjiang railway was performed. The results show that in low cutting without sand control wall, aerodynamic forces of the train are larger.When the sand control wall is located some distances from the windward side of the cutting, the aerodynamic forces decrease obviously. When the distance L=5 m, the resistance force, side force, lift force and overturning moment of the whole train on the windward line reduce by 25.0%, 88.9%, 75.4% and 83.6%, respectively, while on the leeward line,they reduce by 44.2%, 82.2%, 74.4% and 76.5%. With the decrease of the distance, the pressure on the windward surface of train changes from positive to negative and the negative pressure on roof of train reduces. The whole train body is basically in a little negative pressure environment so that the stress condition is improved significantly.