Aerodynamic Shape’s Theoretical Study And Partial Heighten Optimization Of The Earth Type Wind Break-wall Of Lanzhou-Xinjiang Railway Line

Lanzhou-Xinjiang Railway Line is located in the areas with severe wind disasters, and strong cross-wind has a serious impact to the safe operation of trains. For this reason,the Ministry of Railways construct lots of earth type wind break-wall along the Lanzhou-Xinjiang Railway. On the one hand,because of the large aeolian along the railway, Parts of the symmetrical earth type wind break-wall’s windward side integrable sand, leading to "non-symmetrical" shape result in the wind break function decreased.On the other hand, with the increase of train speed, the protective effect of existing earth type wind break-wall urgently need to improve.This paper, based on scientific subject,includes aerodynamic shape’s theoretical study and transformation of the earth type wind break-wall of Lanzhou-Xinjiang Railway Line.This paper, with box car for representing vehicle type, use three-dimensional numerical simulation method to analyze the form factor of the earth type wind break-wall,and get the influence law of wind-proof performances about the shape factor of the earth type wind break-wall.Then according to these factors,we discusse the theoretical optimized project and obtain the most suitable transformation method to the present earth type wind break-wall.At last,we use a local heightening method to optimize the different forms of existing earth type wind break-wall,and obtain the best heighten height through analyzing the vehicle overturning moment and flow field. The conclusions of the study are as follows:(1) The reasonable increasing height at the top of the existing earth type wind break-wall in Lanzhou-Xinjiang Railway Line is able to improve the wind-proof performances effectively;(2) The2.0m and2.4m high symmetrical earth type wind break-wall’s optimal heightening height is separate0.4m and0.28m;the overturning moment of the vehicle in the first-line decreased by98.2%,99.3%respectively than the original earth type wind break-wall’s.(3) The optimal heightening height is separate0.9m、0.64m and0.54m for the asymmetrical earth type wind break-wall whose windward side is separate0m、1m and2m high;the overturning moment of the vehicle in the first-line decreased by97.9%、91.1%、93.2%respectively than the original earth type wind break-wall’s.The results have important guiding meaning for transformating the existing earth type wind break-wall. And it also has a certain reference value for building the new wind break-wall and further study of the aerodynamic performance of the wind break-wall.