Study On MHD Modelandtemperature Distribution Of Pantograph-Catenary ARC

Pantograph-catenary system has been one of the most important equipment of high-speed railway. If its excellent performance cannot be guaranteed, the safety of high-speed railway will be in danger. And pantograph-catenary arc, resulting from the breakdown of gap between pantograph and catenary when they separate suddenly, has been Pantograph-catenary system critical issue and attracted more attention for its damage to contact materials. What aggravates pantograph-catenary arc damage to contact materials is that the traction current has been growing, which makes the energy of pantograph-catenary arc stronger and stronger, with the constant increasing of the high-speed railway operation speed. On one hand, when pantograph-catenary arc occurs, the transient temperatures of electrodes surfaces are very high, and make the electrodes materials to be eroded seriously. For this reason, surfaces of contact materials become rougher, which exacerbates the abrasion with relative sliding between pantograph and catenary. On the other hand, because of the function of high temperature it is possible that plastic deformation occurs on the surface of catenary wires, which weaken wires’ tensile strength and even make them broken. For improving contact material and enhancing its ability to resist arc erosion, works on the temperature distribution of pantograph-catenary arc can’t remain undone.Based on MHD theories, a pantograph-catenary arc mathematical model, which consists of properties of arc plasma and also involves electromagnetic, heat and radiative phenomena, has been established in this paper. A fluid dynamics software FLUENT has been adapted and extended by self-written routines, and a two-dimension static pantograph-catenary arc geometry model considering coupled heat transfer between solid electrode and fluid arc has been built.Then reasonable boundary conditions of flow field and electromagnetic have been set for this two-dimension geometry model. Through the analysis of calculation results, the distribution characteristics of arc shape, current density and electric field in arc column have been explored. And this paper also discussed the temperature distribution of arc column and the interior of arc cathode and arc anode. In addition, some experiments were done to prove the validity of this model. Studies on factors affecting arc temperature distribution, such as arc current, thermal conductivity of contact materials and profile of catenary wire, have been done to seek effectively methods reducing arc erosion in this paper. Thermal conductivity of pantograph materials has important influence on their internal temperature being dropped while increasing thermal conductivity of materials. Increasing the radius of contact surface of arc and catenary will be helpful to enhance its anti-arc erosion performance because that it can reduce the maximum temperature in the catenary when arc occurs.