Experimental Determination of Some Micro-Structural and Hydrous Properties of a Terra Cotta and Modelisation of Hygrothermal Transfers

This experimental study present some micro-structural and thermo-hydrous properties of terra cotta. A tube, built from this porous material, bathes in a tank filled with water. The internal surface of the wall carries a water film which evaporates by forced convection of hot and dry air, allowing the storage of negative kilocalories. The form of the tube used is a factor that allows neglecting the variations of the thermo-physical properties of the air between the entry and the exit of the tube. A computer code (based on the equation of Darcy for fluid crossing saturated porous material, the equation of Laplace on pressures and the equation of heat in polar co-ordinates) was established to describe the thermo-hydrous behavior of the material. The code makes it possible to determine the zones of intrinsic permeability favorable to a continuous evaporation without draining off the water film and it also allows the calculation of the average temperature of bath.