New equations for heat and mass transfer in the turbulent flow in pipes and channels

An equation was derived for the calculation of heat and mass transfer coefficients in the case of pipe and channel flow, taking into account the experimental data for high Reynolds and Prandtl numbers. The equation is valid for the transition region and for the range of fully developed turbulent flows. It is pointed out that it is not possible to obtain a generally valid heat transfer equation in the form proposed by Nusselt (1909). An equation of general validity can, however, be derived by making use of the fundamental form developed by Prandtl (1944) on the basis of momentum theory.