Research On Performance Of Aerodynamics Brake Panel On High-Speed Train Based On SPH Method

While the high-speed railway has become a developing trend,the higher train speed explicitly requires more for braking.The traditional adhesive braking systems are restricted by the sticky limits between wheel and rail,but the restriction does not exist in non-adhesive braking systems.As the supplement to adhesive braking systems,non-adhesive braking methods such as aerodynamics braking enhances the braking ability of high-speed trains,which is significant to the operation safety of high-speed trains.Using the Smoothed Particle Hydrodynamics(SPH)method,a two-dimensional fluid-solid coupling model of the aerodynamic brake panel was established,based on a high-speed train model,the system realized the dynamic numerical simulation of the whole braking process in different max opening angle conditions which increases by 5? from 0?to 90?.To verify the consistency of aerodynamic characteristics of a braking panel at different speeds,comparing and analyzing the laws of aerodynamic resistance and lift during the braking process in different max opening angle conditions at the speed of 300km/h,325km/h,and 350km/h.To ensure the rationality of the selection of the max opening angle,comparing and analyzing the laws of aerodynamic resistance and lift relevant to the opening angle under three-speed conditions,and suggestions for the selection of max opening angle of the aerodynamic braking device.Besides,a two-dimensional dynamic numerical simulation of the braking panel with the max opening angle 80? was conducted for 0.26 seconds at the speed of 300km/h.And the braking performance of the braking panel was verified by the movement law,the force distribution,the laws of braking force,and lift.The aerodynamic characteristics of a braking panel under different speeds are almost the same,only the difference in numerical values and the rate of change.The force on the braking panel increases steadily in the rotating process,but the braking panel will suffer strongly impact at the sudden stop moment,and it can provide stable and considerable braking force after opening.In addition to generating horizontal braking force,the braking panel can also provide the lift,which is conducive to improving the contact between wheel and rail.The maximum braking force of braking panel under three speeds all appeared between 75? and 85?,not when vertically opened.Lift is an approximate sinusoidal distribution with the symmetry axis of ?(28)65?.Therefore,on the premise of obtaining the maximum braking force,it is recommended to select 80? as the maximum opening angle,which could improving the contact between wheel and rail at the same time.The whole rotating process of a braking panel takes about 0.03 seconds,which meets the requirement of rapid response in an emergency.At the first moment,the force on a braking panel is distributed in a gradient from top to bottom,resulting in bending deformation easily.Due to the blocking effect caused by the right angle edge of a rectangular braking panel,a stress concentration phenomenon happens in the right angle edge,so the force is always more significant than that of other parts,that is why the rectangular braking panel has a better resistance effect.The force distribution of other components is equivalent,and the force level is lower.