The Study On Aerodynamic Shape Optimization Of Inter City Train

The aerodynamic problem caused by the running high-speed train has became one of the main restriction factors of train’s speed up. With appropriate optimized aerodynamic shape, the aerodynamic performance of the train could be effectively improved. The aerodynamic simulation model of an Inter City train was established by CFD software. The aerodynamic design variables including the bottom structure type, head streamline shape, cross section, height and wide of the Inter City train body were optimized by different methods, which contain the comparison method and multi-objective optimization method. There are several aspects of research achievement as follows:1. With the comparison of the influence of different bottom structure types on the aerodynamic performance of Inter City train running under various working conditions, it found that the train with an equipment bay is much more suitable when running in open field and under crosswind, while the train with apron board show better aerodynamic performance both passing each other and entering a tunnel.2. The direct optimization model of train’s aerodynamic shape based on genetic algorithm NSGA-II and indirect optimization model which applied approximate model were established. Various approximate models were analyzed and compared. One proper calculative strategy for train’s aerodynamic shape optimization was found.3. The three-dimensional parametric model of the Inter City train was established by the Hicks-Henne shape function. When Inter City train is under crosswind the total aerodynamic drag force and the capsizing moment of the head car were set as optimization objectives, and the multi-objective optimization design of train’s aerodynamic shape based on combination of genetic algorithm and approximate model was carried out. The aerodynamic performance of optimized train under crosswind was obviously improved. The response relationship among speed of crosswind, velovity of train and the aerodynamic performance of train under crosswind was built.4. A method for aerodynamic shape optimization of a train under multi-conditions was explored. The integrated shape optimization design was carried out. The total aerodynamic drag force in open field and the capsizing moment of the head car under crosswind were set as optimization objectives. The aerodynamic performance of optimized train both in open field and under crosswind was effectively improved.