Solution of heat transfer inverse problem in thin film irradiated by laser

Abstract

The presented article deals with inverse problems in nanoscale heat transfer identification problems [1]. Heat flow in solids can be modelled using various models. When dealing with objects of small dimensions, of the order of nanometres, and with fast heating processes, comparable to relaxation times, then it is reasonable to use molecular dynamics or the Boltzmann transport equation (BTE) [2]. The presented coupled system of Boltzmann transport equations has the advantage over molecular dynamics that it has a less complicated mathematical apparatus and calculations proceed faster. A thin film irradiated by ultrashort laser pulse is modeled using BTE. Heat transfer parameters of the model are identified using evolutionary algorithm – an optimization algorithm inspired on biological evolution of species. Multicriterial identification is characterized as an optimization problem where the difference between obtained and expected results is minimized.