Modeling And Simulation Research Of Pantograph Catenary Arc Characteristics And Its Interaction With Pantograph Catenary Materials

Pantograph-catenary(PC)arc occurs frequently and ignites severely due to the increasing speed and heavy load of the train.PC arc will ablate the pantograph strip and the contact wire seriously to threaten train's stable running.PC arc has become the key factor to limit train for further speed-up and development.Therefore,the research on the physical characteristics of PC arc is of great significance to understand the PC materials damage caused by PC arc and to find out the solution to control the PC arc as well as reduce the PC materials ablation.Up to date,there remains some problems in the researches on the PC arc.The PC arc theoretical model is incomplete.Researches on the effect of the natural environment on the PC arc characteristics as well as the PC arc on the PC material ablation are insufficient.Therefore,the PC arc model is improved.The influence of the natural crosswind on the PC arc dynamics is studied in detail.And the contact wire ablation caused by the lowering pantograph arc during the pantograph lowering process is investigated.A more perfect PC arc model is built based on the magnetohydrodynamics(MHD)with the electrodes taken into consideration.The simulation model in this paper is validated via the comparison between the arc characteristics in this model and the data in the related literatures.The impact of the PC arc current and the impact of the PC gap distance on the PC arc characteristics are studied based on the improved PC arc model.It is found that the arc column radius has a significant effect on the arc resistance.The influence of the natural crosswind on the PC arc dynamic characteristics is modeled with the natural crosswind taken into account.The effects of the PC arc current and the crosswind velocity on the PC arc temperature and the PC arc voltage are studied.The periodic oscillation caused by the Karman vortex street is found in PC arc shape,arc temperature curve and arc voltage curve when the crosswind is higher than 15 m/s.The oscillation amplitude of the PC arc voltage is mainly determined by the PC gap distance,while the oscillation period of the PC arc voltage is mainly determined by the contact wire radius.The moving mesh method is utilized to simulate the lowering pantograph process and the surface deformation of the contact wire,by which the lowering pantograph arc model and the contact wire ablation model are established.The arc heat flux density and the arc pressure during the pantograph lowering process are obtained based on the lowering pantograph arc model.And the effect of the PC arc current on the heat flux density and the arc pressure is investigated.The influence of the arc current and the Marangoni effect on the contact wire ablation is studied based on the contact wire ablation model.It is found that the Marangoni effect has a significant effect on the flow characteristics of the molten pool and the surface deformation of the contact wire.The positive Marangoni surface tension coefficient drives the molten pool to flow to the central region,while the negative Marangoni surface tension coefficient drives the molten pool to flow in the opposite direction.In the latter case a smoother surface was observed,which is benefit for the current collection system.