Numerical Study of Forced Convection Film Condensation in a Channel with Porous Walls

Abstract

This work presents a numerical study of laminar film condensation of a pure saturated vapor under forced convection inside a vertical plane channel whose walls are covered with a porous material. The mathematical model, based on the conservation equations of mass, momentum, and energy, is solved using a finite difference method. The flow in the porous layer is described by the Darcy-Brinkman-Forchheimer model. A comprehensive parametric analysis was conducted to examine the influence of nine dimensionless numbers on the liquid film thickness (δ*) and the corresponding heat transfer performance, characterized by the Nusselt number (Nu). The results indicate that the film thickness increases with increasing dimensionless thermal conductivity (λ*), Prandtl number (Pr), and dimensionless viscosity (ν*), which in turn reduces the Nusselt number. Conversely, the film thickness decreases, and the Nusselt number increases, with higher Reynolds number (Re), Froude number (Fr), Jakob number (Ja), porosity (ε), and dimensionless channel thickness (H*). The channel aspect ratio (L/A) was identified as the most dominant parameter affecting both film growth and heat transfer. While the model is validated against existing analytical work, providing a robust theoretical framework, direct experimental comparison remains a scope for future investigation. These findings offer critical insights into the coupled hydrodynamics and thermal phenomena, providing practical guidance for the design and optimization of high-performance compact heat exchangers that leverage porous media to enhance condensation.