Effects of shaft and tunnel portal on coupled aerodynamic characteristics of 600 km/h superconducting maglev train

Abstract

To address the severe aerodynamic effects caused by a 600 km/h superconducting maglev train passing through a tunnel at full speed, this study systematically investigates the coupled influence of auxiliary facility parameters including the shaft (location L, cross sectional dimension W, height h), tunnel portal (cross sectional area S), and openings (spacing D, side length F) on the evolution of tunnel aerodynamic effects. By integrating three dimensional unsteady flow field numerical simulations with a dynamic model testing system, the research notably reveals the regulatory mechanisms of these parameters on the evolution characteristics of the initial compression wave pressure gradient and the multi peak structure of micro-pressure waves. The results show that shaft parameters significantly affect the initial compression wave. Both the wave amplitude and gradient exhibit a linear negative correlation with cross sectional dimension W and a linear positive correlation with location L, while demonstrating a nonlinear relationship with height h, the amplitude follows a cubic polynomial trend, and the gradient initially increases before plateauing. Under the configuration W=8 m, L=50 m, and h=20 m, substantial reductions in both compression wave amplitude and gradient were achieved. The portal cross sectional area S shows a “U-shaped” relationship with the compression wave gradient, with the maximum gradient reduction of 53.24% occurring at S=210 m², a result comparable to that achieved with optimized opening parameters (D=15 m, F=3.5 m, 53.96%). Regarding micro-pressure waves, the amplitude measured 20 m from the tunnel exit shows a linear positive correlation with shaft parameters L and W, while the influence of h saturates beyond 50 m. Reductions exceeding 54% were achieved with portal parameters, either at S=210 m² or using the optimized opening configuration. Furthermore, micro-pressure waves near the portal exhibit a consistent dual peak structure: the first peak originates from the train entry compression wave, and the second results from further wave compression after tunnel exit. The opening location governs selective peak regulation openings near the portal entrance primarily suppress the first peak with minimal impact on the second, whereas centrally located openings reduce the first peak but can amplify the second by up to 3%. Based on these insights, an optimized parameter configuration is proposed: a shaft with a cross-sectional dimension ⩾8 m located 50 m from the portal, a portal cross sectional area of 210 m², and openings spaced at 15 m intervals. This configuration can reduce the initial compression wave gradient by over 50%. The results provide a theoretical foundation for controlling aerodynamic effects of superconducting maglev train.

Keywords

superconducting maglev train / shaft / tunnel portal / initial compression wave / pressure gradient / micro-pressure wave

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