高速列车进入有缓冲结构隧道的压力变化研究

采用高速列车空气动力学模型实验对高速列车在进入带缓冲结构隧道过程中瞬变压力传播机理进行研究。实验结果表明,缓冲结构能够减缓隧道内瞬变压力。其原因在于:缓冲结构横断面积逐渐由大变小,阻塞比逐渐由小变大,延长了压力上升时间,降低了压力梯度;另一方面,由于压缩波在缓冲结构和列车、隧道之间多次反射,降低了压力峰值。在M.S.Howe提出无缓冲结构下最大压力波变化理论基础上提出有缓冲结构时隧道内最大压力和最大压力梯度变化规律计算公式。所得结论可为隧道空气动力学研究提供参考。

Study on Changes of Pressure Waves Induced by a High-speed Train Entering into a Tunnel with Hood

The propagation mechanism of the pressure waves induced by a high-speed train entering into a tunnel with hood was studied by using the high-speed train aerodynamics model research system.The results show that the hoods can alleviate the magnitude of the instantaneously changing pressure wave inside the tunnel.On the one side,the cross section area of the hood changes from large to small gradually,so the block ratio of the tunnel changes from small to large gradually,thus prolonging the pressure raising time and reducing the pressure gradient;on the other side,the maximum pressure is decreased because multi-reflection of compression pressure waves occur among the hoods,the train and the tunnel.The formula of the changing law of the maximum pressure and the maximum pressure gradient inside a tunnel with hood was presented on the basis of the formula of the changing law of the maximum pressure in a tunnel without hood by M.S.Howe(1999).The result is helpful for future research on the aerodynamics of tunnels.