Laser non-conduction limited heating and prediction of surface recession velocity in relation to drilling

Lasers find application in modifying the characteristics of metallic surfaces in industry. In the present study, a laser non-conduction heating situation is investigated and the recession velocity of the surface is computed after considering: (a) constant temperature evaporation at the surface and (b) the steady evaporation condition. It is found that, in the initial phase of evaporation, the velocity of the liquid-vapour interface (recession velocity) predicted from constant temperature evaporation at the surface condition is more realistic than that corresponding to the steady evaporation situation. Moreover, as evaporation progresses, the magnitude of the surface temperature increases because of recoil pressure developed at the vapour-liquid interface. Consequently, the surface temperature rises and the recession velocity is determined from a steady heating situation in place of that predicted from constant temperature evaporation at the surface condition.