Influence of Thickness of the Porous Layer on Thin Film Condensation in Forced Convection in a Canal Whose Walls are Covered with a Porous Material: Determination of Lengths of Entry

Abstract

We have examined film condensation in a channel whose walls are covered with porous media numerically. The transfers in the porous medium and the liquid film are respectively described by the Darcy-Brinkman-Forchheimer model and the equations of the hydrodynamic and thermal boundary layers and are solved by the decentered implicit finite difference method and the iterative Gauss-Seidel method.
 After validating, the influence of the thickness of the porous layer on the longitudinal velocity and the temperature profiles in both media (pure liquid and porous medium), the thickness of the liquid film, the local Nusselt number and the lengths of entry have been studied.
 We note that an increase in the thickness of the porous layer increases the friction and decreases the contact of the fluid with the cold plate and allows a decrease in the longitudinal velocity and an increase in the temperatures in the porous medium and the pure liquid, a decrease liquid film thickness (disadvantaged condensation) and increases the local Nusselt number and also an increase in the length of entry. The increase in length of entry is quasi-linear. The sensitivity of condensation to a change in thickness of the porous layer is constant.