A numerical methodology for simulations of multi-mode heat transfer during a selenization process for CIGS (Copper Indium Gallium Selenide) solar cell films has been developed. Turbulent fluid dynamics and convective heat transfer are simulated using a finite-volume large-eddy simulation (LES) technique while thermal conduction and radiation are predicted using finite-element methods. The computational methodology is validated for three heat transfer modes. Using the technique, a numerical study of heat transfer during the selenization process for deposition of a CIGS layer is performed to analyze the thermo-fluid phenomena occurring during the process. The present method is found to well predict temperature distribution on substrates as a function of both space and time. It is also analyzed that how turbulent fluid motions alter temperature distributions on the substrate during the selenization process. (C) 2018 Elsevier Ltd. All rights reserved.