The interaction phenomena between laminar forced convection and thermal radiation in a participating medium inside a curved pipe was studied numerically. The working fluid inside the curved pipe was assumed to be absorbing, emitting, and isotropically scattering. The fluid entering the inlet of the pipe was assumed to be in uniform condition and the wall of the pipe under constant temperature and emissivity. The P-1 radiation model was applied to the combined convection-radiation simulations. The three-dimensional governing equations for laminar flow and heat transfer were solved with a control volume finite element method (CVFEM), which is of second-order accuracy. The effects of thermal radiation on the convective flow and heat transfer were measured by comparing the numerical results with and without thermal radiation. The comparison shows that although thermal radiation can significantly alter the temperature field, it relatively weakly affects the velocity fields in the curved pipe. When thermal radiation is considered, both the convective heat transfer and the total heat transfer in the curved pipe can be substantially enhanced.
