The heat transfer of a single solid cylindrical poly(ether imide) (PEI) pellet in polyethylene (PE) melt under simple shear flow was studied using experiments and numerical simulations. This included two approximate 2-D representations of the geometry, and a rigorous 3-D geometry matching the experimental conditions. A generalized power-law viscosity model for PE melt, and temperature-dependent conductivity and specific heat were used for PEI in the models. Viscous dissipation was included in the simulations. From the experimental temperature history, the mean heat-transfer coefficient h̄ was determined to be 370 W/m2 · K, with the assumption of a uniform convective environment. From the simulation, h̄ was determined to be 1,160 W/m2 · K and 420 W/m2 · K in the 2-D simulations with circular and rectangular pellet, respectively, and 250 W/m2 · K for the 3-D simulation. Results from the 3-D simulation proved that the uniform convection assumption used to calculate h̄ for the experiment was not acceptable.