| High-speed trains are not only affected by train winds,but also by natural winds during operation.Due to the mutation of natural wind,accidents may occur due to the separation between pantograph and catenary or excessive contact force at the moment of wind speed mutation.Therefore,it is of great significance to study the aerodynamic characteristics of pantograph under sudden wind field,improve the stability of pantograph under natural environment sudden wind,and ensure the safety of pantograph and train.Based on summarizing previous studies,the aerodynamic characteristics of pantograph in abrupt wind field are studied.Firstly,the influences of vehicle speed,wind direction Angle,extreme wind speed and hoisting bow height on the aerodynamic characteristics of pantograph components in the abrupt wind field were studied,and the aerodynamic characteristics of pantograph were compared with those of the whole pantograph under the corresponding conditions of steady cross wind.Secondly,the time-domain characteristics of pantograph aerodynamic parameters at different vehicle speeds,different wind angles,different extreme wind speeds and different bow heights under abrupt wind field are discussed,as well as the outflow field characteristics and time-domain analysis curves of pantograph under separate vortex model.The aerodynamic characteristics of pantograph under open operation and closed operation are compared.Finally,the resistance ratio of the pantograph in the abrupt wind environment was analyzed,and the structure of the bow head with the greatest resistance was improved,and the aerodynamic characteristics of the bow head before and after improvement were compared to put forward feasible suggestions for the structure of the pantograph.The results indicate that the lateral force difference of pantograph under abrupt wind and cross wind is proportional to the vehicle speed,and the maximum gap is reached when the vehicle speed is 400km/h.In addition,the lateral force of pantograph under abrupt wind is 231 N larger than that under cross wind.The difference between the resistance values of pantographs under sudden wind and cross wind is inversely proportional to the wind direction Angle.When the wind direction Angle is 15°,the difference between the resistance values of pantographs is the largest,reaching 238 N.Meanwhile,the resistance of bow head,upper frame and lower arm is also the largest.The influence of lift height on the upper frame is significant,and the range of aerodynamic characteristics is the widest among the three components.Under the change of vehicle speed,wind direction Angle and extreme wind speed,the sudden wind has greater influence on the aerodynamic characteristics of pantograph than the cross wind.In the open condition,the aerodynamic performance fluctuates greatly,and the lift fluctuation even reaches2312.6%.The stability is not as good as that in the closed condition.In order to reduce the influence of pantograph on train running,the closed running direction should be selected as far as possible.The resistance of pantograph mainly concentrates on the bow head,which accounts for about 62% of the total resistance of the three components.Compared with the prototype,the resistance of the improved bow head is reduced by 41.5% on average.The streamlined and wavy groove design of the improved bow head greatly reduces the resistance of the bow head and improves the flow receiving quality of the pantograph. |
