Wet Surface
This node should be used to model evaporation from and condensation to a solid surface completely covered with liquid water. It adds the evaporation flux to the boundary conditions of Equation 7-4 of Moist Air (MT Interface) node, and computes the corresponding latent heat source to be added in the heat transfer equation.
It can be applied on the exterior boundaries of a domain where the Moist Air (MT Interface) node is active.
The evaporation flux gevap (SI unit: kg/(m2⋅s)) is defined as:
where Mv is the molar mass of water vapor (SI unit: kg/mol), K is the evaporation rate factor (SI unit: m/s), csat is the saturation concentration of vapor (SI unit: mol/m3), and cv is the vapor concentration (SI unit: mol/m3).
The latent heat source qevap (SI unit: W/m2) is obtained by multiplying the evaporation flux by the latent heat of evaporation Lv (SI unit: J/kg):
Wet Surface Settings
Enter a value or expression for the Evaporation rate factor K.
See Moist Surface node for the computation of the amount of liquid water accumulated on a solid surface partially covered with liquid water, due to evaporation and condensation.
When a Heat and Moisture multiphysics coupling node is active, the resulting latent heat source is automatically added as a boundary heat source into the heat transfer equation.
Location in User Interface
Context menus
 Moisture Transport in Air>Wet Surface
Moisture Transport in Building Materials>Wet Surface
Ribbon
Physics Tab with interface as Moisture Transport in Air or Moisture Transport in Building Materials selected:
Boundaries>Wet Surface