Modeling and simulation of melt flow during discharge crater formation in EDM

摘要

To improve the accuracy of the discharge crater formation simulation in EDM,in this study a thermo-hydraulic coupling model based on finite element method was built,which comprehensively considered temperature-dependent material properties,buoyancy force,vaporization recoil pressure and Marangoni effect,to investigate the melt flow during the discharge crater formation.According to the simulation results,main conclusions can be drawn as follows.1.On the initial stage of discharge when arc plasma is expanding,vaporization recoil force acts on the melt pool surface is the main factor that drives the molten electrode material flow to the periphery of discharge crater.2.When the vaporization recoil force decreases to a small value due to the expansion of arc plasma,the thermo-capillary force caused by Marangoni effect becomes the main factor that drives the radial flow of the molten electrode material and that promote the formation of bulge.3.After the end of discharge,the crater radius will continue to increase and crater depth will experience fluctuations under the influence of surface tension,and bulge height continue to increase a little under the effect of thermo-capillary force.