Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.
The present work presents a numerical approach using the hybrid differential transform/finite difference method to study heat transfer in a thin film exposed to ultrashort-pulsed lasers. This problem involving high energy flux caused by lasers within a very short duration is formulated based on the hyperbolic two-step model that includes the features of finite speed of thermal wave and the coupling effects of energy flux between the electron-lattice systems. The governing equations are transformed from the time domain into the spectrum domain using the differential transform technique. The numerical solutions are obtained through a recursive process associated with the discretized equations in the space domain using the finite difference method. An axisymmetric case of a gold film subjected to a laser beam is given as a numerical example. Both the electron and lattice temperatures are obtained by the proposed method.