Objective Based on the actual operating conditions of high-speed train routes, and in view of complex tunnel environments such as tunnel length, line gradient, and altitude, it is necessary to study the in-compartment pressure comfort in order to achieve more accurate simulations and to analyze the effectiveness and applicability of the existing pressure protection logic under complex tunnel line conditions.

Method Based on the generalized Riemann variable characteristic line method of the one-dimensional compressible unsteady non-isotropic flow model, and in combination with the pressure protection valve opening/closing control logic and the vehicle airtightness, the in-compartment pressure characteristics of trains under complex tunnel line environments are simulated. For tunnels with different lengths, gradients, and altitudes, the in-compartment pressure fluctuations and the opening and closing characteristics of the pressure protection valve are analyzed when high-speed trains pass through tunnels, and the characteristics of in-compartment pressure under the influence of multiple factors are summarized. For the case of high-speed trains passing through long-large tunnels, the numbers of pressure protection valve opening/closing under different tunnel gradients are statistically analyzed.

Result & Conclusion  When trains pass through tunnels, tunnel length, gradient, and altitude all affect the number and timing of pressure protection valve opening/closing. The existing pressure protection logic can meet the requirements for the in-compartment composite pressure comfort; however, when the train runs continuously uphill in a long-large tunnel, the pressure protection valve remains in a continuously closed state.