高速列车不同位置受电弓非定常气动特性研究

Research on Unsteady Aerodynamic Characteristics of Pantographs in Different Positions of High-speed Trains

为研究高速列车不同位置受电弓的非定常气动特性,基于计算流体动力学理论,建立高速列车空气动力学模型。列车模型采用八节编组,包括头车、六节中间车和尾车。受电弓为双弓模型,包括一个升弓和一个降弓,安装于第一节中间车的前端或后端,或者安装于第六节中间车的前端或后端。采用分离涡模拟(Detached eddy simulation,DES)方法对明线无横风环境下运行的高速列车周围流场进行数值模拟,列车运行速度为350 km/h,得到高速列车不同位置受电弓受到非定常气动力的时域特性、频域特性以及受电弓周围非定常流场结构。结果表明:受电弓安装位置沿列车纵向向后,受电弓气动阻力和升力的时域均值都呈减小的趋势;升弓开口运行时,受电弓气动升力时域均值都小于闭口运行时,升弓滑板气动升力和侧力的波动幅值也都小于闭口运行时;升弓滑板的升力和侧力波动呈现典型的宽频分布特性,其主要频率位于0~300 Hz范围内。

To study the unsteady aerodynamic characteristics of pantographs in different positions of high-speed trains, the aerodynamic models of high-speed trains are established based on the theory of computational fluid dynamics. A train with eight coaches is adopted as the train model, which includes a head coach, six middle coaches and a tail coach. The pantograph model has two pantographs, which includes a lifted pantograph and a folded pantograph. The pantographs are fixed on the front end or the rear end of the first middle car, or fixed on the front end or the rear end of the sixth middle car. The flow fields around high-speed trains running in the open air without crosswinds are numerically simulated by the detached eddy simulation（DES） method. The train running speed is 350 km/h. The characteristics of the unsteady aerodynamic forces acting on the pantographs fixed in different positions of high-speed trains are presented from the numerical results, which include the characteristics of the time domain, the frequency domain, and the unsteady flow structures around the pantographs. The results show that the time-average values of the aerodynamic drag force and lift force of the pantographs tend to decrease as the fixing position of pantographs moves backward along the longitudinal direction of the high-speed train. When the lifted pantograph is in the knuckle-downstream direction, the time-average values of the aerodynamic lift forces of the pantographs are smaller than those with the lifted pantograph in the knuckle-upstream direction, and the amplitudes in the aerodynamic lift force and side force of the sliding plate of the lifted pantograph are also smaller than those with the lifted pantograph in the knuckle-upstream direction. The fluctuations of the lift force and side force of the sliding plate of the lifted pantograph have broad frequency distributions, and their main frequencies range from 0 Hz to 300 Hz.