Thermal analysis of electrode heating and melting due to a spark

A thermal analysis has been carried out to estimate the temperature distribution in an electrode and the shape and size of molten metal pool due to heat from a single spark. Analytical solutions for heat conduction in a semi-infinite solid subjected to various boundary heat sources (point source, disk source, and Gaussian source-all instantaneous and semicontinuous) have been compiled and listed. In all cases, but one, the latent heat of melting has been assumed to be zero. The analysis shows that the instantaneous point source results in the largest radius and depth of the molten metal pool, and the highest efficiency of melting (about 61%). The maximum error in the calculated volume of the pool, assuming zero latent heat of melting, is estimated to be less than 15%. A comparison of the calculated radius of the molten metal pool with the crater dimensions of eroded surfaces shows that the point heat source does not satisfactorily account for the crater dimensions.< >