Study On Security Of 200km/h High Speed EMU Severing In Crosswind

As the development of China Railway, the aerodynamics of the high speed EMU, especially the security of it in crosswind is worth emphasizing. This paper makes a target to a type of high speed EMU in China and it studies the security in crosswind when the high speed EMU runs on the Qinshen line of China and high interference line of Germany. At last, the limit speed of the power cars is presented.Firstly, it studies the theory of train aerodynamics and derives the basic control equation of the three-dimensional flow field around the power car. Some reasonable hypothesizes are made as precondition before the aerodynamic mathematical and physical model are set up. Then it studies and analysis the train aerodynamics with one of the CFD (computational fluid dynamics) softwares, FLUENT. At last, the results of aerodynamic forces and moments are given. Through comparing, the trend of the pressure coefficient curve in the paper is consistent with some of the experimental study in correlation literatures. The results have a reference value. Results show that aerodynamic forces and moments of the power car have the same tendency in both the constant crosswind and gust conditions. Except in some speed, resistance and lift of the head car are smaller than middle car and tail car, all of the aerodynamic forces and moments of head car are larger than middle car and tail car and show a tendency of linear increase.Secondly, multi-body dynamic model of the power car is built and its critical velocity is computed with the German multi-body dynamic software, SIMPACK. The result shows that the linear critical velocity is 540km/h and non-linear critical velocity is 410 km/h. Both of them are higher than the design speed which is 200km/h.Then it studies the effect of loading time on the security index of the power car when the aerodynamic results are loaded to the multi-body dynamic model. According to the paper, 2 second is used as the loading time of the wind load.Lastly, the limit speed is obtained when the high speed EMU runs on the Qinshen line of China and high interference line of Germany in line constant crosswind condition, gust condition and curve constant crosswind condition. The results show that the dynamic security index is more conservative when the power car runs on the Qinshen line of China than it runs on high interference line of Germany.