Study On Crossing Air Pressure Pulse And Aerodynamic Performance Of High-speed Maglev Trains Meeting In The Open Air

The maglev train is different from the common ground traffic,it does not use the friction force as the driving force,but the use of magnets between attraction and repulsion,and the train suspended in orbit at the same time to gain momentum.The maglev train has many advantages compared with the traditional wheel rail train,which includes low noise,strong line adaptability and low energy consumption.There has been a certain gap between high-speed rail and civil aviation,and Maglev Transport system can perfectly compensate for this gap,which can achieve comfortable travel in medium and long distance.Lateral force will affect the driving stability of maglev train.Aerodynamic lift will affect the size of the gap between the bottom and the track of maglev train,and the adverse effect on the stability and safety of maglev train is more than that of wheel rail train.Therefore,the research on lateral force and lift of maglev train is essential.The rendezvous pressure wave is a huge pressure shock caused by the instantaneous change of the air flow at the gap between the two vehicles when the two vehicle is rendezvous.When the pressure wave generated not only affect the passenger comfort,more likely to make the train head and side windows broken seriously.Therefore,it is necessary to study the aerodynamic performance of the maglev train.There are many factors affecting the pressure wave,such as train speed,slenderness ratio,intersection degree,line spacing of streamlined train.This paper mainly studies the change of pressure wave on the open line with different speeds and different vehicle rendezvous.At the same time,the intersection of pressure waves will also cause the body to change the force of the moment,making the body swaying,seriously affecting the stability of the vehicle.In this paper,a mathematical model and a physical model for solving the three dimensional,viscous,compressible,unsteady and turbulent flow fields of a maglev train are established with the model of high speed maglev train as the research object,and the overlapping grid method is used to realize the relative motion of two trains.First,the pressure wave results of the Shanghai Maglev Test are compared with the calculated results of the pressure wave,and the feasibility of the overlapping grid technology used in this paper is verified and the idea of grid division is reasonable.Secondly,the change characteristics of the pressure wave and the aerodynamic force of the maglev train at different speeds are analyzed by the above numerical method.The amplitude of the pressure,lateral force and lift are all increased with the increase of the intersection speed.Finally,the model with longer curve head is introduced.The numerical simulation method is used to compare the change characteristics of pressure wave and aerodynamic force during the intersection of two different head type maglev trains.It is concluded that the new vehicle has a more gentle response to the pressure waves and is more conducive to driving stability.At the same time,the change amplitude of lift and lateral force of new vehicle intersection is smaller than that of TR08 maglev train.