基于延迟脱体涡算法高速列车通过隧道时的绕流特性

基于延迟脱体涡算法和滑移网格技术,建立CRH380A型列车的含有转向架的三维可压缩瞬态仿真模型,模拟研究高速列车气动力、速度场和表面压力这3大绕流特性的变化规律。结果表明:延迟脱体涡算法能较好地捕捉列车通过隧道时的气动特性;当列车头部刚驶入隧道时,气动阻力迅速升高并在车头完全进入隧道时达到最大值,列车下方2侧的速度纵向分量会急剧增加,位于靠近设备舱位置的速度纵向分量会显著降低;当尾车刚驶入隧道时,隧道内壁与列车侧面之间的流场会出现回流区;当尾车全部刚驶入隧道时,气动升力和侧向力骤然增加;当列车全部驶入隧道后,气动力的波动幅值均明显升高;列车通过隧道过程中,列车侧面压力整体上呈现先增后减、最后维持周期性波动的趋势,处于尾流区的车尾部位具有更强烈的波动特征;列车裙板和车底的表面压力整体上均呈先减后增、最后维持在较高幅值波动的趋势,对列车相关结构的疲劳强度产生不利影响。

Characteristics of Air Flow around Train Passing through Tunnel Based on Delayed-Detached Eddy Simulation Algorithm

Based on the Delayed-Detached Eddy Simulation(DDES) algorithm and sliding mesh method, a 3D compressible transient simulation model of CRH380A train with bogies is established to study the variation laws of 3 major flow characteristics, i. e. the aerodynamic force, velocity field and surface pressure around highspeed train. Results show that DDES algorithm can better capture the aerodynamic characteristics of the train passing through the tunnel. When the train head just enters the tunnel, the aerodynamic drag increases rapidly and reaches the maximum when the train head completely enters the tunnel. The longitudinal component of the speed on both sides under the train will increase sharply, and the longitudinal component of the speed near the equipment cabin will significantly reduce. When the tail car just enters the tunnel, the flow field between the inner wall of the tunnel and the side of the train will have a recirculation zone. When the tail car just enters the tunnel completely, the aerodynamic lift and lateral force suddenly increase. When the train enters the tunnel completely, the fluctuation amplitude of aerodynamic force increases obviously. In the process of the train passing through the tunnel, the lateral pressure of the train increases first, then decreases, and finally maintains the periodic fluctuation trend, while the tail part of the train in the wake area has stronger fluctuation characteristics. The surface pressure of the train skirt and bottom plates shows the trend of decreasing first, then increasing and finally maintaining a higher amplitude fluctuation, which has a negative impact on the fatigue strength of the train related structures.