升力翼对列车气动特性及运行安全性的影响研究

Influence of lift wings on aerodynamic characteristics and operation safety of trains

为探究升力翼高速列车的可行性,结合列车空气动力学和车辆多体系统动力学理论,建立了有/无升力翼高速列车空气动力学模型和车辆系统动力学模型,对有/无升力翼高速列车在明线无风及横风运行环境下的气动特性及运行安全性进行了仿真研究。研究结果表明:安装升力翼可提升高速列车的气动升力及升阻比,但气动阻力也大幅度增大;有/无翼高速列车周围流场特性差异较大,安装升力翼后列车表面压力分布及流线流向改变,列车滑流速度峰值增大,两侧及尾流区域速度分布改变。横风下列车表面压力分布及背风测涡脱结构改变,头车受到的气动阻力、升力、侧力及点头力矩相比于无翼时有明显的增大,升力与侧滚力矩差异明显,侧滚力矩方向改变且数值增大,摇头力矩变化很小。明线无风下,安装升力翼能够减小6%~13%的轮轨垂向力,其中尾车由于气动升力最大,轮轨垂向力减幅最显著;运行速度在450 km/h及以下时升力翼高速列车能够安全平稳运行,运行速度在500 km/h时升力翼高速列车轮轨垂向力和轮重减载率超限;影响安全性的主要原因是升力翼扩大了各节车之间气动载荷的差异,升力翼的气动布局有待进一步改善,建议减小头车和尾车的升力;横风环境下,升力翼高速列车头车受到升力、侧力及侧滚力矩数值明显增大,运行安全性恶化,横风安全域缩小。

Based on the theory of train aerodynamics and vehicle multi-body system dynamics,aerodynamic and vehicle system dynamics models of a high-speed train with or without lift wings were established to explore the feasibility of a lift-wing high-speed train.The aerodynamic characteristics and running safety of a high-speed train with or without lift wings were simulated and studied in calm and crosswind environments.The results showed that the aerodynamic lift and lift-to-drag ratio of high-speed trains can be improved by installing lift wings;however,the aerodynamic drag also increases significantly.Furthermore,the differences in the flow-field characteristics of high-speed trains with or without wings were significant.After installing the lift wings,the surface pressure distribution and the streamline flow direction of the train changed.The peak value of the slipstream velocity of the train increased,and the velocity distribution in the areas on both sides and in the wake of the train changed.Under crosswinds,the surface pressure distribution and backflow-vortex structure of the train changed.The aerodynamic drag,lift,lateral force,and pitching moment on the head train increased significantly compared to when wings were not present.The difference in the lift and rolling moments was evidentwith a change in direction and an increase in the numerical value of the rolling moment.The change in yaw moment was minimal.When no wind exists on the open line,the installation of lift wings can reduce the wheel-rail vertical force by 6%~13%,with the largest reduction occurring in the tail car owing to the maximum aerodynamic lift.The lift-wing high-speed train could operate safely and stably at speeds up to 450 km/h,and the wheel-rail vertical force and wheel load reduction rate exceeded the limit at a speed of 500 km/h.The main reason for the impact on safety is that the lift wings increase the difference in the aerodynamic loads between each car.The aerodynamic layout of the lift wings requires further improvement,and the reduction of the lift on the head and tail cars is suggested.Under crosswind conditions,the head car suffers from a significant increase in the lift,lateral force,and rolling moment,thereby deteriorating its operational safety and reducing the crosswind safety domain.