Study On Aerodynamic Effect And Comfort Of High Speed Railway Underground Platform

In recent years,the construction and development of high-speed railways at home and abroad have developed rapidly.It has become a trend to build railways and stations underground in large cities.Compared with the trains running on the open line,the personnel in the underground space will be more significantly affected by the train wind.When the train passes through the underground station,the aerodynamic effect on the platform will change dramatically,which makes the passengers feel uncomfortable.Therefore,it is necessary to study the aerodynamic effects on the underground platform and the impact on the comfort of personnel when the train passes through the station,which will provide a reference for the optimal design of the underground railway station.Based on the underground high-speed railway station of Beijing Daxing Airport,this thesis used the numerical simulation method to establish the aerodynamic coupling model of the tunnel-underground station-train in front of the station through the sliding grid technology.The aerodynamic effects and comfort of the platform of high-speed trains at different speeds were studied.Finally,according to the wind comfort criteria,the comfort of personnel on the underground platform was evaluated.The main research contents and results are as follows:(1)The underground high-speed railway platform was simulated,and 25 measuring points were arranged on the platform to monitor the change of aerodynamic effect on the platform.When there was no platform screen door on the platform,the train passed through the underground station at four speeds 200 km / h,250 km / h,300 km / h,and350 km / h.The two cases of single-car passing and double-car crossing were discussed.Different groups of measuring points were divided in two directions on the platform,and the wind field fluctuation changes at different positions were compared and analyzed.(2)When the platform was equipped with a screen door,the train generated a violent aerodynamic effect,which was compared with the typhoon field of the station without the screen door.The research shows that the screen door can significantly weaken the station aerodynamic effect caused by train wind.The wind field fluctuation on the platform increases with the increase in train speed.The aerodynamic effect on the platform is more complex when two vehicles meet than when one vehicle passes.When the bicycle passes through the station,the wind field fluctuation at the entrance and exit of the platform is more severe than that at other locations.When the two cars meet,the wind field in the middle of the platform fluctuates more violently;the aerodynamic effect on the platform decreases with the increase of the distance from the platform edge.(3)When there was a passenger transfer in the underground station,the aerodynamic comfort of the platform was studied by the train wind generated by a single-running train.From the three angles of train speed,platform position,and distance to the edge of the platform,the changes in different wind environments on the platform were studied.According to the mechanical effect of train wind and the wind comfort criterion,the comfort of platform personnel was evaluated.It is found that when the train passes,the peak wind speed of the platform decreases exponentially with the distance to the edge of the platform.In the case of no screen door,the uncomfortable interval has appeared when the speed of the intersection train reaches 250 km / h;in the case of screen doors,the wind speed of the platform is basically within the comfortable range,and the less comfortable wind speed fluctuation range is small.