Research On Aerodynamic Characteristics Of High Speed Train Pantograph Based On Non-smooth Structure

The aerodynamic noise caused by pantograph is one of the main noise sources of high-speed train.To explore the effect of drag and noise reduction of the pantographs based on non-smooth structures,this paper aims to change the surface structure of pantograph and then suppress the vortex zone around the pantograph,so as to achieve the purpose of reducing aerodynamic noise and drag.The aerodynamic characteristics of the non-smooth structural pantographs were studied by using the three-dimensional fluid numerical simulation method,based on the theories of fluid dynamics and aero-acoustics,and the main contents in this paper were as follows.Firstly,a section of smooth rob with same size of pantograph was selected as the study object,and the modification design of this section of smooth robs was carried out.The main idea of design was to synthesize different types of member structures according to the owls and shells’ appearance.Therefore,six different bionic type robs of pantograph were designed.Using the three-dimensional steady-state CFD calculations,the aerodynamic characteristics of non-smooth surface members and the smooth members were compared and analyzed,in order to explore the non-smooth surface structural types of robs which achieve drag and noise reduction effect.The results show that the groove and the zigzag structural robs based on bionics can indeed affect the distribution of flow field,achieving the effect of reducing drag and noises.What’s more,the contact strips of DSA380 type pantograph were also selected as research object,and the explored zigzag surface structure with drag and noise reduction effect,where coupled to the smooth surface contact strips again.Considering that the non-smooth surface structure couldn’t affect conveying electricity between the conveying electricity lines and the contact strip,so the zigzag surface type was applied to the bottom of the contact strip.By the three-dimension fluid simulation method,the aerodynamic characteristic of the new type contact strips,with different width parameter w of zigzag surface structures,was calculated and analyzed at various speed conditions.The results show that,with the increase of the width w,the whole drag and noise will increase first and then decrease.For drag,the aerodynamic characteristics of new type contact strips shows have the drag-increasing effect in the range of width w of 0～10mm.While the width w exceeds 10 mm,the contact strips with the parameter w have the effect of relative reducing drag,and as the width w becomes larger and larger,the better and better is the drag reducing.On the other hand,in the range of the width w of 0～8mm,the new type contact strips have increasing noise trend at various speeds.While the width w exceeds 8mm,the contact strips with the parameter w have the effect of reducing noise.And the width w becomes larger,the noise reduction effect becomes better.At the same time,the results also found that the flow coupling effect of the double contact strips can also reduce the drag coefficient value.