一种用于高速列车受电弓区域气动减阻的新型鞘翅目仿生导流罩

A novel bionic Coleoptera pantograph deflector for aerodynamic drag reduction of a high-speed train

受电弓区域是列车气动阻力的重要来源,其贡献率约为10%,是列车气动阻力的关键区域。因此,改善受电弓区压力分布成为减小列车气动阻力的潜在有效方法。基于鞘翅目昆虫的生物形态,提出了一种新型的仿生鞘翅目导流罩,将其安装在8节编组的高速列车受电弓区域,以实现该区域的空气流动平顺。建立了原始模型(模型Ⅰ)、带导流罩的受电弓Ⅰ(模型Ⅱ)、带导流罩的受电弓Ⅱ(模型Ⅲ)、带导流罩的受电弓Ⅰ和受电弓Ⅱ(模型Ⅳ)4个计算模型,探讨列车气动减阻机理,提高列车气动性能。结果表明,安装受电弓导流罩后,受在电弓区域的气动阻力显著减小。受电弓Ⅰ区域最大减阻达84.5%,受电弓Ⅱ区域最大减阻为25.0%。当受电弓Ⅰ区域和受电弓Ⅱ区域同时安装导流罩时,受电弓Ⅰ区和受电弓Ⅱ区总减阻可达49.6%。与没有导流罩的原始模型相比,受电弓区域的空气流动更顺畅,堵塞效应更小。但是,下游流速加快,冲击风挡区域,导致气动阻力增大。在受电弓Ⅰ区域或受电弓Ⅱ区域安装导流罩时,8节列车的总阻力分别降低了4.6%和1.8%,而在受电弓Ⅰ区域和受电弓Ⅱ区域同时安装导流罩时,列车的总阻力降低了6.3%。本文可为新一代高速列车的气动设计提供参考。

As an important source of train aerodynamic drag,the pantograph area is a key region which takes up about 10%contribution of the total.Thus,improving the pressure distribution in the pantograph area becomes a potential and effective method of reducing train aerodynamic drag.Based on the biological pattern of Coleoptera,a novel bionic elytron(i.e.,deflector)installed on the pantograph areas of an eight-car grouping high-speed train was proposed to smooth the flow.Four calculation cases were set up,i.e.,the original model(Model I),pantograph I with a deflector(Model II),pantograph II with a deflector(Model III),and pantograph I and II with deflectors(Model IV),to explore the mechanism of aerodynamic drag reduction for the train and improve its aerodynamic performance.The results show that after installing the pantograph deflector the aerodynamic drag force of the pantograph area is significantly reduced.The maximum drag reduction in pantograph I region is up to 84.5%,and the maximum drag reduction in pantograph II region is 25.0%.When the deflectors are installed in both pantograph I and pantograph II areas,the total drag reduction in pantographs I and II areas can be achieved by 49.6%.The air flows over the pantograph area in a smoother way with less blockage effect as compared to the base case without deflectors.However,the downstream flow velocity speeds up and impacts the corresponding region,e.g.,windshields,leading to an increase of aerodynamic drag.When the deflector is installed in the area of pantograph I or pantograph II alternatively,the total drag of the eight-car group train reduces by up to 4.6%and 1.8%,respectively,while the drag reduction can be up to 6.3%with deflectors installed in both pantograph I and II areas.This paper can provide references for the aerodynamic design of a new generation of highspeed trains.