Numerical and experimental turbulent heat transfer results for a one-sided heated rectangular duct

Complementary numerical and experimental studies were made of the heat transfer characteristics of a hydrodynamicaUy developed turbulent flow passing through a flat rectangular duct. One, of the principal walls of the duct was maintained at a uniform temperature different from the fluid inlet temperature, while the other walls of the duct were adiabanc. Results were obtained for the local, quasi-local, and average Nusselt numbers in the thermal entrance region and for the fully developed Nusselt number. Both heal and mass transfer versions of the problem were investigated. Excellent agreement prevailed between the experimentally and numerically determined quasi-local Sherwood numbers at a succession of axial stations in the mass transfer entrance region, thereby establishing the analytical model and the numerical solution method. Heat transfer results for airflow were obtained from the numerical solutions for Reynolds numbers between 10, 000 and 100, 000. It was found that away from the immediate neighborhood of the onset of heating the Reynolds number dependence of the local Nusselt number was virtually the same at all axial stations. The one-sided heating condition gave rise to relatively long thermal entrance lengths.