Non-Fourier heat conduction in a thin gold film heated by an ultra-fast-laser

Abstract

Based on the dual-phase-lagging (DPL) heat conduction model, the Cattaneo-Vernotte (CV) model and the improved CV model we investigate the one-dimensional heat conduction in gold films with nano-scale thickness exposed to an ultra-fast laser heating. The influence of system parameters on the temperature field is explored. We find that for all the non-Fourier heat conduction models considered in this work, a larger Knudsen number normally leads to a higher temperature. For the DPL model, the large ratio of the phase lag of temperature gradient to the phase lag of heat flux reduces the maximum temperature and shortens the time for the system to reach its steady state. The CV model and the improved CV model lead to the similar thermal wave behavior of the temperature field, but the thermal wave speeds for these two models are different, especially for large Knudsen numbers. When the phase lag of temperature gradient is smaller, the difference between the DPL model and the improved CV model is not significant, but for the large phase lag of temperature gradient the difference becomes quite significant, especially for the large Knudsen number. In addition, the effect of the surface accommodation coefficient, which is a parameter in the slip boundary condition, on the temperature field of the gold film heated by ultra-fast laser pulses is investigated based on the DPL model.