Aerothermal Characteristics of Maglev Transportation in Evacuated Tube with Different Blocking Ratios

At present,the speeding up of high-speed railways faces challenges such as wheel-rail adhesion, aerodynamic drag,aerodynamic noise and crosswind instability.Combining maglev with the sealed low vacuum tube can greatly break through the speed limit of ground rail transit.However,the maglev train running inside the tube,like piston movement,will make the flow field inside the tube more complex,and aerodynamic heat problems will be more significant.Based on the 3-D,steady and compressible Reynolds-averaged Navier-Stokes equations and SST k-ω two-equation turbulence model as well as the wind tunnel model,the motion of a high-speed maglev train in a tube is simulated.Through numerical calculation,the influence of different blockage ratios on aerodynamic thermal environment,aerodynamic force and flow field structure of maglev train running at 1000 km/h in a tube with an initial pressure of 0.1 atm was investigated.The results show that the total resistance and the temperature rise of the train body surface increase gradually with the increase of blocking ratio.At the stagnation point of the head of the train,the temperature of the head is higher,and the temperature of the head varies greatly.At the tail of the train,the temperature of the surface is lower,and the lowest temperature of the surface of the train appears at the tail.A local supersonic zone appears at the tail of the train,resulting in a large shock wave.The temperature of the air flow in this area will be greatly reduced.When the air flow passes through the shock wave,the temperature will rise sharply again.The analysis results can provide a theoretical basis for selecting different blocking ratios of evacuated tube maglev transportation.