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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:
(4-106)
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:
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ξ (SI unit: kg/m3) is the moisture storage capacity.
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δp (SI unit: s) is the vapor permeability.
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(dimensionless) is the relative humidity.
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psat (SI unit: Pa) is the vapor saturation pressure.
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T (SI unit: K) is the temperature.
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Dw (SI unit: m2/s) is the moisture diffusivity.
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G (SI unit: kg/m3·s) is the moisture source.