Boundary layer analysis of buoyancy-driven two-phase flow in capillary porous media

The boundary layer analysis of buoyancy-driven two-phase flow in capillary porous media reveals that the boiling boundary layer is wider than the condensing boundary layer. A two-phase crossflow pattern represents both the boiling and the condensing flow. The unsaturated flow theory is invalid for the condensing flow, and a two-phase model predicts the capillary effect on film condensation heat transfer.