The Wall Condensation Model has been developed for use in the nuclear containment industry, although it can be used in more general situations. In this model, the condensation of gaseous vapor in a variable composition mixture is driven by the concentration gradient at the wall, and internal boundary mass sources are used to model the removal of condensate from the system. The condensate film thickness, and heat transfer through it, are assumed to be negligible and are not modeled explicitly. This is appropriate for containment scenarios where the condensate does not adhere to the surface but is absorbed by it (for example, on ceramic/concrete walls).
The wall condensation model has two formulations: one for laminar flow and one for turbulent flow. The formulation for laminar flow has been developed for a specific case; it has a hard-coded saturation temperature threshold (623 in solver units of temperature: Kelvin by default) and requires a fine, uniform, and orthogonal, mesh near the wall (such as an inflation layer).
Note: For laminar flow cases, you should avoid using the laminar flow formulation of the wall condensation model by modeling as a turbulent case if possible.
Detailed information about the Wall Condensation Model is available in Wall Condensation Theory in the CFX-Solver Theory Guide.
The following topics are discussed.