| The main principle of this braking method is to shorten the braking distance of the train without friction,so as to ensure the safety of the train.Therefore,wind resistance braking has the characteristics of energy saving,environmental protection,no pollution and no wear.When the train encounters an accident,the wind resistance braking can also be started in time,which has obvious advantages compared with other braking methods.Therefore,this paper uses the numerical simulation method to analyze and study the aerodynamic characteristics and braking performance of high-speed train wind resistance brake plate,hoping to provide technical reference for the in-depth research of China’s high-speed railway in the field of train braking in the future.In this paper,the simulation model of high-speed train with brake plate on the roof under the open line running flow field was established,and the three-dimensional,steady-state and realizable equation turbulence model in fluent simulation software was used to analyze the aerodynamic characteristics and braking performance of wind resistance brake plate in the process of emergency braking of high-speed train.The main research contents are as follows:(1)The numerical simulation of a single set of brake plates installed on the train roof was carried out,the braking force and pressure characteristics of the brake plates arranged at different positions were compared,and their influence on the aerodynamic characteristics of the flow field of the front and rear vehicles was analyzed,so as to obtain the influence of the brake plates on the aerodynamic performance of the train;(2)By changing the number of brake plates and the distance between brake plates,comparing the braking force,explore the optimal installation position of each row of brake plates,and formulate the optimal layout scheme of brake plates;(3)Conduct numerical simulation for four different speeds of300km/h,350km/h,400km/h and 500km/h,and observe the applicability of brake plate under different speeds;(4)Calculate the braking force when the brake plate was installed at the optimal position at different speeds,calculate the shortened braking distance,and evaluate the braking effect of the brake plate.The results show that when the brake plate is installed near the streamlined tail end of the head vehicle and the tail vehicle,the braking force is large,and the maximum braking force is0 m away from the streamlined tail end of the head vehicle,and the braking force reaches2954N;After the brake plate is installed on the train,the total resistance becomes larger,and the braking force of the brake plate plays a leading role in the change of the resistance of the whole train;The optimal layout scheme of brake plates is: install 5 wind resistance brake plates on the roof of each section of the train,a total of 15,and the distance between each brake plate is 2m;At different initial speeds,the braking effect produced by the wind resistance braking device is very significant.When the initial speed is 500km/h,the shortened braking distance can reach 4326.453 m,which is 19.56% less than that without brake plate. |
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