400 km/h高速铁路隧道初始压缩波产生机理研究

Study on Initial Compression Wave Generation Mechanism in 400 km/h High-Speed Railway Tunnel

摘要: 本文基于三维仿真软件，采用CR450动车组头型及隧道的气动模型，对列车进入无缓冲结构隧道和京沪线某隧道缓冲结构的湍流流场进行数值模拟。列车以时速400公里驶入隧道，车前大部分空气受到挤压沿列车行进方向传播进入隧道，部分空气通过环状空间或缓冲结构开孔处逸出隧道。当列车鼻尖抵达隧道入口，初始压缩波开始形成，随着列车头部曲线段进入隧道，压缩波压力急剧增大。当列车曲线段完全进入隧道时，车前压力增加变得平缓，此时初始压缩波完全形成。在列车前方15 m的范围内，压缩波受到列车近场压力的影响，呈现明显的三维特征。当压缩波传播至列车前方15 m的范围外，列车近场压力的作用几乎消失，压缩波呈现明显的一维特性，此时已从三维波演化为一维波。初始压缩波的压力梯度存在先增大后减小，呈现明显的单峰性。缓冲结构可以降低初始压缩波在形成过程中的压力增长速度，但对压力幅值的降低效果还与头型等其他因素有关。

Abstract: This paper is based on three-dimensional simulation software, using the aerodynamic model of CR450 locomotive head and tunnel to numerically simulate the turbulent flow field of a train entering a tunnel without hood and a tunnel buffer structure on the Beijing-Shanghai line. The train enters the tunnel at a speed of 400 km/h. Most of the air in front of the train is squeezed and propagates into the tunnel along the train’s travelling direction, and part of the air escapes out of the tunnel through the annular space or the opening of the hood. When the nose of the train arrives at the entrance of the tunnel, the initial compression wave starts to form, and as the curved section of the train’s head enters the tunnel, the pressure of the compression wave increases dramatically. When the curved section of the train completely enters the tunnel, the pressure increase in front of the train becomes flat, at which time the initial compression wave is completely formed. In the range of 15 m in front of the train, the compression wave is affected by the near-field pressure of the train, showing obvious three-dimensional characteristics. When the compression wave propagates beyond the range of 15 m in front of the train, the effect of the train near-field pressure almost disappears, and the compression wave shows obvious one-dimensional characteristics, at this time, it has evolved from a three-dimensional wave to a one-dimensional wave. The pressure gradient of the initial compression wave increases first and then decreases, showing obvious single-peak characteristics. The hood can reduce the pressure growth rate of the initial compression wave in the formation process, but the reduction effect on the pressure amplitude is also related to other factors such as the head shape.