Heating of saturated porous media in practice: Several causes of local thermal non-equilibrium

In recent years the industrial applications of porous materials has shown a growing relevance. Most of the technological thermal processes in porous media involve time-dependent thermal conditions. Therefore, the temperature at each point of the material also changes in time. In order to correctly carry out the technological process, it becomes necessary to know the temperature distribution inside the material. This is a problem of heat conduction in a fluid saturated porous media subject to a lack of local thermal equilibrium (LTNE).The purpose of this paper is to elucidate the several causes of LTNE, even in steady or quasi steady heat transfer processes in saturated porous media, and to evaluate the influence of structural characteristic of porous media and the presence of surfactant in the saturating liquid phase.