A FILM MODEL FOR HEAT AND MASS-TRANSFER WITH FOG FORMATION

An analysis is presented of a binary film with fog formation and a negligible induced velocity (traditionally referred to as "Stefan-Nusselt flow"). The governing equations of energy and diffusion, coupled with the saturation condition, are solved and analytical correction factors are derived. Subsequently, the "negligible induced velocity" (NIV) fog film model is applied to channel flow, yielding analytical expressions for the variation of bulk vapour mass fraction, bulk temperature, and the possible creation of bulk fog. Multiplying the NIV correction factor for fog only by the classical film model correction factors for induced velocity, reveals that the product corresponds to the film model correction factors for the combined effects of fog and induced velocity. Furthermore, a thorough comparison with theoretical and experimental results of foregoing two-dimensional studies, concerning fog formation in the presence of free and forced convection, confirms the accuracy of the present fog film model.