Theory for Moisture Transport
Theory for moisture transport in building materials
The Moisture Transport in Building Materials Interface solves for the following equation derived from Ref. 15:
(4-99)
This equation models the moisture transfer as the sum of the capillary moisture flux:
and the vapor diffusion flux:
with the following material properties, fields, and source:
ξ (SI unit: kg/m3) is the moisture storage capacity.
δp (SI unit: s) is the vapor permeability.
(dimensionless) is the relative humidity.
psat (SI unit: Pa) is the vapor saturation pressure.
T (SI unit: K) is the temperature.
Dw (SI unit: m2/s) is the moisture diffusivity.
G (SI unit: kg/m3·s) is the moisture source.