ABSTRACT
Direct contact condensation is usually considered to be a mode of condensation observed when a vapor makes direct contact with a low-temperature liquid and condenses on its surface. However, a vapor condenses onto the liquid surface even in the cases of film and dropwise condensation, neither one of which falling under the category of direct contact condensation. Hasson et al. derived asymptotic Nusselt numbers for direct contact condensation of a vapor onto a cylindrical jet, a sheet jet, and a fan jet. The transport of heat from the vapor to a low-temperature liquid drop is governed by the thermal resistance for condensation at the surface of the drop and the thermal resistance inside the drop. In most cases, however, the former is negligibly small when compared with the latter. When a vapor is injected as discrete bubbles into a pool of subcooled liquid, direct contact condensation occurs while the bubbles are rising toward the free surface.
