强风沙对高速列车冲蚀的数值模拟研究

Numerical Simulation Study on Erosion to High-speed Trains by Strong Sand Environment

高速列车在强风沙环境中行驶对行车安全造成了巨大隐患,因此研究强风沙环境中列车的安全性能十分重要。在研究风沙对高速列车冲蚀情况时,粒子对列车的冲蚀程度可以用冲蚀率来衡量。基于流体动力学理论,利用欧拉-拉格朗日方法模拟风沙对列车头车的冲蚀,基于三维、非定常、不可压缩的Navier-Stokes方程和标准k-ε两方程模型,对不同风沙条件下的列车磨损特性进行数值计算与分析。研究发现:当沙粒入射角度不断增大时,头车最大正压区随之增大,且冲蚀面积也随之增加,其主要冲蚀部位在列车最大正压区;当沙粒入射角度为45°时,头车冲蚀率达到最大值;风速和沙粒浓度不变时,列车头车冲蚀率随沙粒粒径的增加呈先增加后减小,最终趋于稳定的趋势,冲蚀过程存在明显的加速期和稳定期;风速和沙粒直径不变时,头车冲蚀率随沙粒浓度增长呈线性增加。

The high-speed trains running in strong wind and sand environment take great hidden dangers to its safety.Therefore,it is very important to study the safety performance of trains in strong wind and sand environment.When studying the erosion of high-speed trains by wind and sand,the erosion degree of the particles on the train can be measured by the erosion rate.Based on the theory of fluid dynamics,Euler-Lagrangian method is used to simulate the erosion of the wind head and sand on the train,based on the three-dimensional,unsteady,incompressible Navier-Stokes equation and the standard k-εtwo-equation model.Numerical calculation and analysis of train wear characteristics under wind and sand conditions are carried out.Findings are when the incident angle of sand increases,the maximum positive pressure zone of the head car increases,and the erosion area increases accordingly.The main erosion site is in the maximum positive pressure zone of the train;When the incident angle of sand is 45°,the head erosion rate reaches the maximum value;When the wind speed and sand concentration are constant,the erosion rate of the head car increases first and then decreases with the increase of the grain size of the sand,and finally tends to be stable.The erosion process has obvious acceleration period and stable period;When the wind speed and sand diameter are constant,the head erosion rate increases linearly with the increase of sand concentration.