Constitutive equations for simultaneous heat and mass transfer in porous material are derived from the integrated mass, momentum and energy balance equations using the averaging divergence theorem. The temperature and moisture content are used as independent variables. In the energy balance equation the conduction, convection and accumulation of heat and heat source due to phase changes are considered. In the moisture balance equation the accumulation of moisture, the diffusion flow of water vapour, the capillary flow of liquid water and the viscous flow of humid air and water are considered. The boundary layer and interracial balance equations are derived. For transient analysis of the moisture physical behaviour of multilayer constructions a numerical algorithm and a computer program based on the Crank - Nicholson method and quasi linearization is formulated. Some example calculations are presented to illustrate the computer program. The accuracy of the numerical algorithm compared with the analytical solution for a semi-infinite body is presented.
|Place of Publication||Espoo|
|Publisher||VTT Technical Research Centre of Finland|
|Number of pages||78|
|Publication status||Published - 1983|
|MoE publication type||D4 Published development or research report or study|
|Series||Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports|
Kohonen, R., & Määttä, J. (1983). Transient analysis of the thermal and moisture physical behaviour of building constructions. VTT Technical Research Centre of Finland. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, No. 168