电火花加工放电通道的多物理场耦合仿真研究

Multi-physics Coupling Simulation Study of Arc Plasma in EDM

利用多物理场耦合建立了稳态时的放电通道模型,分析稳态时的放电通道温度场、流场及电场分布,并对放电电流和放电间隙对放电通道的影响进行了数值仿真及分析。结果发现:最高温度位于通道中心轴的极间中点,温度自该点向周围迅速减小;放电通道中心轴的压力最大,且压力沿放电通道径向随着半径的增加而减小,沿轴向变化不大;放电通道中心区域的极间介质在两极表面附近沿径向向通道中心轴流动、在间隙中心附近背向通道中心轴流动,从而形成两个以极间中心平面为对称平面的漩涡;极间介质电势在放电通道中心区域呈现出在两极表面附近下降较快、在间隙中心附近下降较慢的不均匀变化趋势,在其他区域均匀变化。

In this paper,the steady-state arc plasma model is established by multi-physics coupling method,and the temperature field,flow field and potential distribution of arc plasma are calculated,and the effects of discharge current and discharge gap on arc plasma are simulated and analyzed numerically.Results show that the highest temperature is at the midpoint of the central axis of the arc plasma between the electrodes and the temperature decreases rapidly from the midpoint to the periphery.The pressure reaches the maximum at the central axis of the arc plasma,and gradually decreases along the radial direction of the arc plasma as the radius increases,but does not change obviously along the axial direction.In the central region of the arc plasma,the dielectric near the surfaces of the electrodes flows radially toward the central axis of the arc plasma and the dielectric near the center of the gap flows away from the central axis of the arc plasma,thereby forming two vortices which are symmetric with the central plane between the electrodes.What′s more,the dielectric potential decreases rapidly near the surfaces of the electrodes and slowly near the center of the gap,while changing evenly in other area.