Effects of bottom deflectors on aerodynamic drag reduction of a high-speed train

底部导流板对高速列车气动减阻的影响

Inspired by the fact that bogies and bottom equipment generally contribute a great deal of aerodynamic drag to high-speed trains,this paper puts forward a simple method of mounting some small deflectors before and/or after the bogie cabins to optimize the underbody flow and reduce the aerodynamic drag of high-speed trains.The flow fields of the high-speed train models with and without bottom deflectors are numerically studied by the IDDES method.The effectiveness and further mechanism of the bottom deflectors on aerodynamic drag reduction are analyzed.It is demonstrated that the bottom deflectors could guide the underbody flow to the ground and prevent it from hitting on the bogies and bottom equipment of the train,resulting in a significant aerodynamic drag reduction effect.Moreover,the effects of different mounting locations of bottom deflectors on drag reduction are discussed as well,and an optimal mounting configuration with a drag reduction effect of up to about 12%is finally obtained.Nevertheless,the mounted deflector is also proved capable of significantly reducing the interference range of the underbody flow and reducing the slipstream of the train,which possesses a higher guarantee for the safety of railway workers and passengers waiting on the platforms.This work provides a new idea for aerodynamic drag reduction of high-speed trains,and is of great significance in energy conservation and consumption reduction.

转向架和车下设备区域是高速列车气动阻力的主要来源之一,基于此,本文提出一种安装于转向架舱前后端的小型导流板装置,以改善列车的底部流动、减小列车的气动阻力.采用IDDES方法对是否安装底部导流板的不同列车模型开展非定常数值仿真,并对导流板的减阻效果和作用机理进行分析.结果表明:底部导流板可以将列车底部高速气流导向地面,减小气流对转向架及车下设备的冲击作用,从而产生显著的气动减阻效果.此外,还讨论了底部导流板不同安装位置对减阻效果的影响,最终得到了实现整车减阻约12%的一种最佳安装方式.同时,导流板还能够减小底部流场在展向上的影响范围,减小列车风,这对铁路沿线工人和平台等候乘客的安全具有更高保障.本研究为高速列车气动减阻提供了新思路、新方法。对节能减耗、可持续发展等具有重要意义.