A two-equation turbulence model with new terms for Coriolis and rotational buoyancy has been used for prediction of heat transfer from the leading and trailing sides of a rotating square channel with radially outward flow. Test cases with different Reynolds, Grashof, and rotation numbers are considered. Modeling terms for the Coriolis and buoyancy effects in the k and epsilon transport equations are shown to give predictions that are in better agreement with the experimental data. Flow separation at the leading wall is found to enhance heat transfer. The mechanism of how separation is explained with a non-dimensional parameter that characterizes an adverse buoyancy force.