Flows in Vertical Channels With Asymmetric Wall Temperatures and Including Situations Where Reverse Flows Occur

Numerical investigations are conducted into steady laminar combined convection flows in vertical parallel plate ducts with asymmetric constant wall temperature boundary conditions. The streamwise diffusion terms in the governing equations are neglected and the resulting parabolic equations are expressed in an implicit finite difference scheme and solved using a marching technique. In certain situations the combination of the size of the ratio |Gr/Re| and the difference in temperature between the walls of the duct is such that the fully developed flow profile, as the streamwise coordinate tends toward infinity, includes reverse flow in the vicinity of the cold wall. Techniques first used in a previous study are employed in finding a solution through the whole domain of the fluid for those situations involving reverse flow in the fully developed region. Comparisons with existing data near the duct entrance and far along the duct show very good agreement.