Numerical study of 3-D microscale heat transfer of a thin diamond slab under fix and moving laser heating

Abstract

Laser heating is one of the most practical operations in the field of solid circuit production and thin condensed film treatment. The correct prediction of the heat propagation and flux into the micro/nanothin slab under laser heating has high practical importance. Many theoretical and numerical investigations have been performed for analysis of micro/nanoheat conduction based on one or 2-D approximations. For moving laser heating of thin films, with asymmetric paths, the one or 2-D analysis cannot be applied. The most appropriate equation for micro/ nanoheat transfer is the Boltzmann transport equation which predicts the phonon transport, precisely. In the present work, the 3-D microscale heat conduction of a diamond thin slab under fix or moving laser heating at very small time scales has been studied. Hence, the transient 3-D integro-differential equation of phonon radiative transfer has been derived from the Boltzmann equation transport and solved numerically to find the heat flux and temperature of thin slab. Regarding the boundary and interface scattering and the finite relaxation time in the equation of phonon radiative transfer, leads to more precise prediction than conventional Fourier law, especially for moving laser heating.