风沙环境下高速列车气动特性分析

Analysis of Aerodynamic Characteristics of High-speed Trains in Aeolian Environment

基于SST k-ω湍流模型和Euler-Lagrange离散相模型,建立了风沙环境下高速列车空气动力学计算模型,研究了不同沙粒浓度、不同风速及不同车速条件下的列车空气动力学性能。计算结果表明:风沙环境下,列车头车迎风侧主要受正压力影响,背风侧主要受负压力影响,最大正压力区域由鼻尖逐渐向迎风侧偏移;由于横风的影响,随着沙粒浓度的增强,头车迎风侧沙粒质量浓度增大,背风侧沙粒质量浓度变化较小;对于固定的车速和风速,头车气动力系数随沙粒浓度的增强而增大,且与沙粒浓度近似呈线性关系;沙粒浓度固定时,头车气动力系数随风速的增大而增大,随着车速的提升,头车气动力系数反而下降;风沙环境下,头车侧力系数、头车侧滚力矩系数可近似拟合为沙粒浓度、侧偏角及合成风速的二次多项式;头车升力系数可近似拟合为沙粒浓度、侧偏角及合成风速的三次多项式。

Based on SSTk-ωturbulence model and Euler-Lagrange discrete phase model,the aerodynamic calculation model of high-speed train in aeolian environment is established,and the aerodynamic performance of train under different sand particle concentrations,different wind speeds and different vehicle speeds is studied.The calculation results show that under the aeolian environment,the windward side of the head car is mainly affected by positive pressure,while the leeward side is mainly affected by negative pressure,and the maximum positive pressure area is gradually shifted from the tip of the nose to the wind ward side.Due to the influence of crosswind,the sand mass concentration on the windward side of the head car increases with the enhancement of sand concentration,while the sand mass concentration on the leeward side changes little.For fixed vehicle speed and wind speed,the aerodynamic coefficient of the head vehicle increases with the enhancement of sand concentration,and it is approximately linear with sand concentration.For fixed sand concentration,the head vehicle aerodynamic coefficient increases with the increase of wind speed,and decreases with the increase of vehicle speed instead.Under aeolian environment,the lateral force coefficient of the head car and the lateral rolling moment coefficient of the head car can be fitted approximately as a quadratic polynomial of sand concentration,side slip angle and synthetic wind speed.The lift coefficient of the head car can be approximatelyfitted as a cubic polynomial of sand concentration,side slip angle and synthetic wind speed.