Conjugate film condensation and natural convection between two porous media separated by a vertical plate (Q5943958)

The paper deals with numerical study of the conjugate heat transfer problem for film condensation and natural convection between two fluid-saturated porous media separated by a vertical heat-conducting plate. The governing continuity, Darcy and energy equations along with the corresponding boundary conditions for film condensation and natural convection are first cast into a non-dimensional form using a nonsimilar transformation. These equations are then solved numerically by a cubic spline collocation method. The non-dimensional parameters which describe this problem are the film-to-plate thermal resistance ratio \(A\), the natural convection-to-film thermal resistance ratio \(B\), and the Jakob number \(Ja\) of the subcooling degree in the film. The numerical results are presented in tabular and graphical forms as functions of \(A\), \(B\) and \(Ja\). The effects of these parameters on the plate temperature distribution, on the locat heat transfer rate on both sides of the plate, and on the average heat transfer rate from the film condensation side to the natural convection side are discussed in detail. The authors show that the thermal resistance parameter \(A\) has a substantial influence on conjugate heat transfer characteristics of film condensation. Thus, as the parameter \(A\) increases, the plate temperature variations decrease, while the local heat transfer rates increase on the upper part of the plate and decrease on the lower part of the plate, respectively. It is also shown that the effect of parameters \(A\) and \(B\) on the overall heat transfer rate is more pronounced than that of the Jakob number. The obtained results are compared with the results from the literature, and the agreement is good.