基于CFD的高速列车空气动力制动风翼板型研究

CFD-based study on aerodynamic brake wind-panel forms for high-speed trfferain

采用流体仿真分析软件FLUENT研究了6种制动风翼板型的流场结构和气动力特性,对比分析了各种制动风翼板型迎风面风压分布、制动阻力以及对列车运行稳定性影响较大的侧向力和升力.采用三维雷诺平均N-S方程(RANS),结合k-ε湍流模型,用有限体积法将控制方程离散求解,用SIMPLE法耦合压力-速度场进行数值求解.结果表明:在各种板型迎风面投影面积相同的情况下,凸板和车顶随形板型迎风面压力分布要比凹板好,凹板在尖角处出现压力突变和应力集中现象,因而凸板和车顶随形板型受力性能更好;凹板制动阻力大小稍大于平板,平板可提供的制动阻力稍大于凸板和车顶随形板,但整体上各种板型制动阻力变化幅值均较小;车顶随形板型侧向力大小相比其他板型很小,所以对列车运行稳定性影响最小;各种板型在z轴方向产生的升力相差不大,数值大小分布在600~800N之间.最后得出车顶随形板型的综合制动性能相对更好.

Based on the fluid simulation software,FLUENTTM,the flow field structures and aerodynamic properties are first investigated into six forms of brake wind-panels.Then,the windward pressure distribution,brake resistance,and side and lifting forces,which significantly impact the train operational safety,are compared and analyzed.By integrating the 3D Reynolds average N-S equation(RANS)with k-εturbulence model,the discrete solution on control equation is obtained via finite volume method,while the numerical solution on coupled pressure-velocity filed via SIMPLE method.Finally,it is found from results that,under the condition of the same windward projection area,the windward pressure distribution and loading performance of convex panel and related roof panel form are better than those of concave panel with pressure mutation and stress concentration at the sharp corners.In addition,the brake resistance of concave panel is slightly larger than flat panel,which is slightly larger than that of convex panel.Generally,the resistance variation of different forms is relatively small,whilst the side force of related roof panel form is relatively small with minimal impact on train operational stability.Moreover,the lifting force difference among different panel forms is small spanning from600 N to 800 N.Therefore,the comprehensive brake performance of related roof panel form is relatively better.