Laser short-pulse heating: moving heat source and convective boundary considerations

The equilibrium heating ceases in the surface vicinity of the solid as the laser heating pulse length reduces to sub-nanoseconds. In this case, one-equation model overestimates the temperature rise in the surface vicinity. In order to account for the non-equilibrium heating, the present study is carried out. The electron kinetic theory approach is considered when modeling the laser heating process. The convective boundary condition and the moving heat source are taken into account in the analysis. The governing equations of heat transfer are non-dimensionalized with the appropriate parameters. The electron kinetic theory predictions are compared with the two- and one-equation model findings. It is found that the electron kinetic theory predictions agree well with the two-equation model findings and the one-equation model overestimates the temperature rise in the substrate. The Biot (Bi) number and the laser scanning speed have a coupling effect on the heat transfer mechanism. In this case, the maximum temperature at the surface reduces considerably by increasing the scanning speed and Bi.