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Dynamic characteristics of car body sealing gaps and its influence on pressure fluctuation in high-speed train

To explore the influence of dynamic characteristics of sealing gaps on the pressure fluctuation in train during passing through a tunnel, static air tightness test is conducted to calculate the equivalent leakage area of gaps and to investigate the dynamic characteristic with the variation of pressure difference. The dynamic leakage process of gaps when passing through a tunnel is simulated numerically and the impact of gaps on leakage flow and internal pressure is analyzed. It is found that 1) the equivalent leakage area of gaps has nonlinear characteristics with different pressure difference, 2) when a train under operation condition with positive pressure, the air is more likely to flow out through the holes under positive pressure, 3) the external section of the hole is obviously impacted by the incoming flow, and the stress condition is worse than other parts, 4) the maximum leakage flow of dynamic equivalent leakage hole, the one second change rate, the three second change rate and the amplitude of the pressure inside vehicle under the model are equal to 43.33%, 55.73%, 45.62% and 48.60% of the fixed equivalent leakage hole, respectively. This study can provide a reference for the determination of equivalent leakage area of high-speed train and the optimization of sealing technology.