BEM numerical simulation of coupled heat, air and moisture flow through a multilayered porous solid

The problem of unsteady coupled moisture, air and heat energy transport through a porous solid is studied numerically using singular boundary integral representation of the governing equations. The governing transport equations are written and solved for the continuous driving potentials, i.e. relative humidity, temperature and air pressure. The boundary and interface conditions are discussed.The integral equations are discretized using mixed-boundary elements and a multidomain method also known as the macro-elements technique. The numerical model uses quadratic approximation over space and linear approximation over time for all field functions, which provides highly accurate numerical results. Three test benchmark examples (moisture uptake in a semi-infinite region, air transfer through a lightweight wall, and moisture redistribution inside a multilayered wall with capillary-active interior insulation), were analyzed to show the applicability and accuracy of the simulation model developed.