Heat transfer characteristics during melting of a metal spherical particle in its own liquid

There are manufacturing applications like surface modification and repair technologies where metal particles go into the superheated melt pool heated by an intense heat source and as the workpiece moves away from the energy source this pool solidifies to form a continuous built-up layer. In the present study two-dimensional axisymmetric Navier-Stokes and energy equations are solved using finite volume method to predict the time required for a metal sphere to melt in a melt pool of the same material. The effect of forced convection, characterised by Reynolds number, and superheat of the melt pool, characterised by Stefan number, has been studied in detail for material of different Prandtl numbers. Effect of buoyancy is neglected for the present investigation. It is found that the effect of convection on melting time is more pronounced if RePr/Ste2/3 is high. The rate of melting of the metal sphere with time under different conditions is also presented. Finally, the heat transfer characteristic is represented by the correlation of Nusselt number with Reynolds number, Stefan number and Prandtl number.