Modeling assumptions for turbulent heat transfer

Current modeling assumptions for turbulent heat transfer are improved through a reconsideration of the Reynolds heat flux transport equation, whose convective and diffusive terms will be neglected to yield approximately valid results for boundary layer-type flows near equilibrium. With respect to the Prandt k-model, the present modeling assumptions lead to a simple algebraic formula for the turbulent Prandt number which is in good agreement with experimental data. On the basis of this expression, the Reynolds heat flux, thermal diffusivity, and temperature profiles are determined for the case of a fully developed turbulent tube flow having a constant heat transfer rate. The Nusselt number is also calculated and compared with measurements.