Heat and Mass Transfer in a Gypsum Board Subjected to Fire

B. Weber
Empa
Swiss Federal Laboratories for Materials Science and Technology
Duebendorf, Switzerland

Heat and mass transfer through a gypsum board exposed to fire is simulated and compared to experimental data. The gypsum board is modeled as a porous medium with moist air in the pores. A dehydration front develops at the fire side and travels through the board, consuming energy and releasing water vapor. The vapor migrates through the porous medium by convection and diffusion, and condenses in colder regions away from the fire.

The model involves several physics interfaces: Heat Transfer in Porous Media, Darcy\'s Law, Transport of Concentrated Species, and Weak Form PDE. The main mechanism is heat conduction. Heat convection by vapor transport has little influence, but condensation and evaporation are important for reproducing the experimentally observed temperature plateau.