In this paper, the CFD (Computational Fluid Dynamics) analysis of the pool film boiling heat transfer on a sphere at saturated conditions is presented. The simulation was performed, in first place, in absence of radiation, and subsequently incorporating it, to determine how the radiation affects to convection and the value of the coupling factor between both mechanisms. The VOF (Volume-of-fluid) method was used to model the multiphase flow and the P-1 method for the treatment of the radiation. A User Defined Function (UDF) was added to the CFD code for the treatment of the mass and energy transfer between the liquid and vapor phases. The results for the convective heat transfer were consistent with the experimental data reported in the literature and with two of the most widely used correlations. The coupling factor between radiation and convection obtained from the simulation analysis was similar to that proposed by known models. (C) 2014 Elsevier Ltd. All rights reserved.