Modelling of thin metal film heating using the dual-phase lag equation with temperature-dependent parameters

The paper presents a mathematical description and numerical algorithm simulating the thermal processes occurring in the metal microdomain subjected to the ultrashort laser pulse. The model of these processes is based on an equation with two delay times (the dual-phase lag equation - DPLE) supplemented by the appropriate boundary and initial conditions. The energy equation is formulated in the version assum-ing the variability of thermophysical parameters with temperature (volumetric specific heat and thermal conductivity are temperature-dependent). Taking into account the geometric properties of the laser beam, the problem is treated as an axisymmetric task, while the thermal impact of the laser is taken into ac-count by the introducing into DPLE a component related to the internal heat sources in the domain con-sidered. At the stage of numerical modeling the implicit scheme of the finite difference method is used. In the program simulating the heating/cooling processes occurring in the metal microdomain, the pos-sibility of the melting and resolidification effects are also considered. In the final part of the work, the numerous examples of numerical computations and the resulting conclusions are presented. It turned out, among others, that especially at high temperatures, the consideration of parameters variability (gold, nickel) causes that the results of numerical simulations differ visibly from classical solutions for the con-stant values of parameters.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license( http://creativecommons.org/licenses/by-nc-nd/4.0/ )