Study On The Aerodynamic Characteristics And Safety Of The High-temperature Superconducting Maglev Train Under Crosswinds

The speed has always been the theme of the times,especially in the field of rail transit.As the increasing running speed of rail transits,the speed improvement space of conventional wheel-rail trains is limited by the wheel-track adhesion and the limiting speed of pantographcatenary.Unlike conventional wheel-rail trains,the high-temperature superconducting(HTS)maglev trains can levitate and guide with its unique pinning properties in a non-contact manner,and with the combination of linear motors for drive,it can avoid the problems such as wheelrail adhesion and the limiting speed of pantograph-catenary,and has great potential to apply in the high-speed and ultra-high speed.However,the HTS maglev trains running in open environment will also inevitably be affected by the crosswinds,which will seriously affect the aerodynamic performance,and safety of maglev train.Therefore,it is necessary to study on the aerodynamic characteristics and safety of the HTS maglev train under crosswinds,so as to provide a reference for the engineering of the HTS maglev train.Firstly,based on the three-dimensional,steady and compressible Reynolds average N-S equation and the turbulence model of the SST k-ω two equations,this thesis establishes the simulation of the HTS maglev train in STAR-CCM+ model with the engineering prototype of HTS maglev train as the research object.Through the grid independence research and the wind tunnel test data of the ICE2 scaled-down model,the rationality of the grid division method and numerical method used in this thesis is verified.The results show that: the results obtained by using the medium grid size have good calculation accuracy and are more suitable for simulation calculations.By comparing the pressure coefficients and various aerodynamic coefficients of the ICE2 scaled-down model simulation results with the wind tunnel test data,it is found that the errors of the two results are small,which indirectly shows that the numerical method in this thesis is reasonable.Secondly,the aerodynamic characteristics of the high-temperature superconducting maglev train in a crosswind environment is studied by the fluid simulaition software STARCCM+.Through numerical simulation methods,the effect of the aerodynamic characteristics of the HTS maglev train is explored with different wind direction angles(0°,45°,90°,135°,180°),different operating speeds(400 km/h,450 km/h,500 km/h,550 km/h,600 km/h),and different cross wind speeds(0 m/s,10.7 m/s,13.8 m/s,17.1 m/s,20.7 m/s).The results show that: except for aerodynamic drag,all aerodynamic loads firstly increase and then decrease with the increase of wind direction angle,and increase with the increase of cross wind speed.However,the increase of operating speed will make all aerodynamic loads increase.Finally,the aerodynamic load obtained from the fluid simulation is loaded into the simplified aerodynamic load center of maglev train,and the dynamic model of the hightemperature superconducting maglev train under the crosswinds is established through the dynamic simulation software UM.Through numerical simulation methods,the effect of the safety of the HTS maglev train is explored with different wind direction angles(0°,45°,90°,135°,180°),different operating speeds(400 km/h,450 km/h,500 km/h,550 km/h,600 km/h),and different cross wind speeds(0 m/s,10.7 m/s,13.8 m/s,17.1 m/s,20.7 m/s).The results show that the safety of the maglev train is the worst when the wind direction angle is 90°,and gradually becomes worse with the increase of the cross wind speed and running speed.