A Theoretical Analysis of Heat Transfer in Turbulent Convection

The two cases of fully developed turbulent flow passing a flat plate at zero incidence and through a tube are considered. The laminar sublayer whose thickness is usually considered as constant at a given Reynolds number is postulated, in effect, to vary with the heat flow. The effect of natural convection is taken into account, despite its minor importance in predicting the heat transfer by forced convection in the turbulent regime. A general formula of Nusselt number is obtained as a function of Prandtl, Reynolds, and Grashof number. The heat transfer by natural convection alone becomes only a particular case and the Nusselt number is readily found by dropping out the term containing the Reynolds number. Calculated results agree excellently with experiments as conducted by previous investigators. (auth