Aerodynamic Characteristics And Safety Analysis Of High Speed Train

When the train speed is relatively low,the pneumatic safety of it does not appear;but with the increase of train speed,aerodynamic characteristics which endanger the security of the train are obvious,and significant changes have taken place in the aerodynamic performance and dynamic performance.And with more and more complex operating environment of the train,the safe operation of it becomes worse.Therefore,it is necessary to study the aerodynamic performance of high speed train in different environments in order to assess the safety of the train.This paper,taking a A-type high speed EMU as the research object and establishing the aerodynamic model of the train by using the fluid analysis software FLUENT,firstly analyzes the air flow field characteristics and the surface pressure distribution of the train in windless conditions;and based on wind-free environment,the paper compares and the characteristics of air flow field and pressure distribution around the train in windy environments,and then further the study of the trends of six types of aerodynamic loads,including the resistance,with different variables(velocity,wind speed and wind direction angle).On the basis of the strong wind model,a user defined function(UDFs)was used to establish the aerodynamic model in FLUENT,with which the paper analyzes air flow field characteristics and surface pressure distribution;and then a systematic analysis of the study of six types of aerodynamic loads,including the resistance,with the effect of different wind time and wind strength;and then the aerodynamic patterns of trains are drawn from the analysis.Based on the theory of multi-body dynamics,the dynamic model of high-speed EMU trains is established with the application of the multi-body dynamics software SIMPACK.According to the dynamic performance evaluation index of Testing specification of High-speed Electric Multiple Unit,the variation trend of the evaluation index such as derailment coefficient,with the different variable(train speed and wind speed)is obtained,and then the safe operational speed of the train in wind-induced environment is obtained.