Heat transfer in porous media - Phase Change

This article, devoted to heat transfer with phase change in porous media, follows on from the article "Heat transfer in porous media. Conduction, convection, radiation" [BE 8 250] , which deals with transport phenomena in porous media.

Phase change phenomena in porous media play an important role in many fields. These include

• exploitation of hydrocarbon deposits. Various thermal methods are used (steam injection, in situ combustion, etc.) which lead to phase change mechanisms;

• thermal insulation, which can be seriously affected by vapour transfer and condensation;

• geothermal energy, transfers between soil and atmosphere ;

• multiphase heat exchangers, fuel cells ;

• chemical engineering ;

• nuclear safety, etc.

Like all multiphase processes, phase change phenomena in porous media are highly complex and, in many respects, our knowledge of them is still only partial. This article looks at the physical processes at work at pore scale and the most common macroscopic models used in drying operations or processes involving boiling.