Effect of localized high temperature on the aerodynamic performance of a high-speed train passing through a tunnel

A moving model (1/20 scale) was used to study the effect of high temperature at the entrance of a tunnel on the aerodynamic performance of a high-speed train passing through it. The air in the tunnel was heated using highly-precise, self-controlling, ultra-thin, silicone rubber heating devices that were firmly attached to the inner surface of the tunnel (covering the first 2 m of the tunnel from the entrance). When the specified temperature was reached, tests were performed using a model train moving at different speeds. The experimental results were used to compare and analyze the pressure fluctuations and propagation of pressure waves under normal and localized high-temperature conditions. The results show that the peak-to-peak value of the transient pressure on the tunnel surface decreases by 5-7% in the presence of a normal ambient and high temperature tunnel mode. In addition, the corresponding difference on the surface of the head of the train is 3-4%. Hoping this experimental study will encourage theoreticians to investigate the mechanism responsible for the generation of transient pressures in localized high temperature railway tunnels. The results can provide guidance and support for researchers seeking to improve passenger safety and comfort in high temperature railways.