Study Of Arc Erosion In Bow Networks Based On Magneto-hydrodynamics

The arch network system consisting of pantograph and contact network is an important link in the transmission of electrical energy,and the arc discharge phenomenon between the arch network is becoming more and more frequent due to factors such as body vibration and hard points of the contact line,causing serious erosion to the contact line and carbon skids.In this paper,based on the multi-physics action of magneto-hydrodynamics,we consider the influence of air flow on the arc and establish a two-dimensional symmetric model of the arc of the bow network to study the arc discharge characteristics of the bow network.The arc temperature at a given operating condition is tested by spectroscopic method and compared with the simulation results to verify the reliability of the model.Finally,based on the erosion characteristics,a further phase change model of the melt pool of the bow-net material is established to study the erosion effect of the bow-net arc on the material,and its main research work is as follows:Firstly.Based on the principle of magnetohydrodynamics,the partial differential equations such as fluid electric field,magnetic field and temperature field are constructed,and the convective heat transfer term is added to modify the heat balance equation.The temperature distribution of pantograph-catenary arc is simulated by COMSOL multi-physical field.Finally,the electric field distribution and temperature field distribution in the arc column are simulated At the same time,a simple pantograph-catenary experimental platform is built,and the arc temperature measured by spectral method is compared with the simulation results,and the temperature difference between the two is within 2%,which verifies the reliability of the magnetohydrodynamic model.Secondly.Based on the data results of pantograph-catenary arc simulation model,its electric field distribution and temperature field distribution On the one hand,it is found that there are high Joule heat concentration and strong Lorentz force in the anode region of arc column and the equipotential lines in the region are dense by comparing the parameters such as current density,electric field intensity and electric field potential On the other hand,the surface temperature of carbon slider is 6.83 times of that of wire,which causes the temperature difference.The main reason is that the thermal conductivity of carbon slider is too small,which leads to the temperature accumulation on the surface of carbon slider.Thirdly.By varying the thermal conductivity of the carbon sliding plate,the radius of the contact line,the distance between the nets and the air flow rate,the temperature distribution between the arc column,the carbon sliding plate and the contact line of the nets was obtained under different parameters.The temperature distribution shows that increasing the thermal conductivity of the carbon slip sheet,increasing the radius of the contact wire and the gap between the wire and the web,and increasing the air flow can effectively suppress the arc heat transfer.Fourthly.Based on the MHD model,the phase transition model of arc molten pool is established The longitudinal erosion velocity of the molten pool is faster than the transverse velocity of the surface,but there will be an incomplete liquid melting region at the boundary of the molten pool,which slows down the internal erosion of the molten pool The flow velocity distribution shows that the surface velocity of the molten pool is8.56 times of that at the boundary,and the evaporation of the molten pool increases with the increase of the flow velocity.