时速600km高速磁浮列车明线非定常气动性能数值模拟研究

Numerical Simulation of Unsteady Aerodynamic Performance of 600km·h^(-1) High-Speed Maglev Train Running on Open Line

基于改进延迟分离涡模拟(IDDES)方法和k-ωSST湍流模型,建立时速600 km等级高速磁浮列车明线单车稳定运行时的三维可压缩非定常数值计算模型,并通过风洞试验验证;分析列车表面压力、列车周围速度流线和旋涡等流场结构,以及列车气动力的时域特性和频域特性。结果表明:高速磁浮列车明线稳定运行时气动力在时均值上下准周期性波动,升力波动幅度较大,尾车升力最大波动幅度为12.48%;各节车气动升力的功率谱密度频率主要集中在0~20 Hz范围内,最大峰值频率均为9.3 Hz;定常模拟和非定常(瞬态)模拟的流场结构在尾流区有明显差异,2种模拟下的气动阻力最大相差2.60%,升力最大相差7.65%;整车摩擦阻力占总气动阻力的78.50%,居主导地位;磁浮列车以400~600 km·h^(-1)速度等级明线稳定运行时,列车气动力与车速平方成正比;气动外形优化时应对设备舱导流区域、风挡和滑撬进行优化。

Based on the Improved Delayed-detached Eddy Simulation(IDDES)method and k-ωSST turbulence model,a three-dimensional compressible unsteady numerical calculation model of 600 km·hhighspeed maglev train is established for the stable operation of single train on open line,which has been validated by wind tunnel experiments.The flow field structures,such as train surface pressure,velocity streamline and vortex around the train,and the characteristics of time and frequency domains of train aerodynamic forces,are analyzed.The results indicate that during stable operation of high-speed maglev train on open line,aerodynamic forces fluctuate around the time-average value quasi-periodically.The fluctuation range of lift force is relatively large,and the maximum fluctuation amplitude of the tail car′s lift force is 12.48%.The frequencies of power spectral density of aerodynamic lift forces for individual trains are mainly concentrated within 0-20 Hz and the maximum peak frequencies are 9.3 Hz.The flow field structures of steady and unsteady(transient)simulations have significant differences in the wake region.The maximum difference between the aerodynamic drag of the two simulations is 2.60%,and the maximum difference between the lift forces is 7.65%.The friction drag accounts for 78.5%of the total aerodynamic drag and plays a dominate role.When the maglev train running at a steady speed within 400-600 km·h^(-1)on open line,the aerodynamic force is approximately proportional to the square of the train velocity.Diversion area,windshield and sled should be optimized during the train aerodynamic shape optimization.