Shock wave behavior and aerodynamic load in maglev-equipped evacuated tubes: Effects of blockage ratio

Abstract

Evacuated tube transportation (ETT) offers a promising high-speed transport solution, but trains operating at supersonic speeds within a sealed tube can induce complex aerodynamic phenomena that impact safety and reliability. This study utilized the Reynolds-averaged Navier-Stokes (RANS) shear stress transport k-ω (SST k-ω) turbulence model for steady-state simulations and the improved delayed detached eddy simulation (IDDES) SST k-ω model for unsteady-state simulations, both coupled with the advection upstream splitting method (AUSM). Four tunnel cross-sectional areas (49 m², 64 m², 81 m², and 100 m²) with corresponding blockage ratios (β) (0.253, 0.192, 0.150, 0.121) were analyzed to explore shock wave formation and its dependence on blockage ratios, along with surface pressure distribution and aerodynamic loading. Results show that higher blockage ratios increase shock wave intensity, while larger tunnel areas reduce this intensity, improving flow structure and wake effects. Moreover, as the blockage ratio decreases, the total drag coefficient of the entire train decreases linearly. When the blockage ratio decreases from 0.253 to 0.121, the total drag coefficient of the entire train decreases by 46.2%, with the head carriage and tail carriage drag coefficients decreasing by 23.3% and 32.7%, respectively, while the drag coefficient of the middle carriage remains nearly unchanged. The percentage of the total drag coefficient contributed by the head carriage decreases from 51.1% to 40.9%, while the percentage for the tail carriage increases from 47.0% to 56.6%. These findings enhance understanding of ETT fluid dynamics and performance.

Keywords

maglev train / evacuated tube transportation (ETT) / blockage ratio / shock wave / aerodynamic load

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