导流装置对高速磁浮列车气动特性的影响

Effect of deflector devices on the aerodynamic characteristics of high-speed maglev trains

由于车轨悬浮间隙的存在,高速磁浮列车的悬浮架周围流场紊乱且气动力复杂,影响列车的悬浮和导向性能。基于计算流体力学建立了3车编组的高速磁浮列车气动数值仿真模型,研究了列车气动特性及车轨间隙和悬浮架周围的流场结构,分析了3种不同形式的导流装置(板式、短楔形、长楔形)对列车气动特性的影响规律。研究结果表明:在500 km/h的运行速度下,气流通过头车鼻尖底部悬浮间隙直接冲击在头车一位端悬浮架迎风侧,形成的压差阻力使头车气动阻力大幅增大;受悬浮架扰流影响,气流在车体底部形成了大面积的正压区,直接导致头车气动升力和气动力矩大幅提高且远高于中间车及尾车气动升力。根据研究结果,改变头车鼻尖底面结构,控制进入车轨磁浮间隙的气流流量和方向,改善了列车表面压力分布情况,协同降低了列车气动阻力、气动升力和点头力矩。与原型磁浮列车相比,3种导流装置均能实现减阻降升,其中气动特性优化效果最好的长楔形导流装置可实现减小整车气动阻力3.6%、头车气动升力40.6%和头车点头力矩80.3%,综合气动性能最好。

Due to the existence of suspension gap,the flow field around the suspension frame of high-speed maglev trains is turbulent and aerodynamically complex,which in turn affects the suspension and guidance performance of the trains.Based on Computational Fluid Dynamics(CFD),a numerical simulation model of the three-car marshalling high-speed maglev train is established to study the aerodynamic characteristics and the flow field structure.The results show that the airflow through the suspension gap impacts directly on the windward side of the suspension frame of the head car at a speed of 500 km/h.This creates a differential pressure drag which increases the aerodynamic drag of the head car significantly.A large area of the positive pressure area is formed at the bottom of the car body due to the airflow turbulence of the suspension frame,leading to a large increase in the aerodynamic lift force of the head car that is much higher than that of the middle car and the tail car.According to the results,three different types of deflector devices are proposed to control the airflow through the gap by changing the structure of the nose of the head car,which can significantly improve the pressure distribution on the train surface.The aerodynamic drag,aerodynamic lift and pitch moment of the train are effectively and synergistically reduced.Compared with the original maglev train,all three types of deflector devices(plate,short wedge,long wedge)can achieve both aerodynamic drag and lift forces reduction,among which the best long wedge deflector device can reduce the overall aerodynamic drag force by 3.6%,the head car aerodynamic lift by 40.6%and the head car pitch moment by 80.3%,with the best comprehensive aerodynamic characteristics.