A non-instantaneous kinetic model for freezing in porous media

摘要: Abstract A solution is presented for the moving boundary problem that arises during heat and moisture transfer, when freezing fine-grained porous media under phase transition conditions. It based upon a quasi-heterogeneous scheme. This scheme assumes existence of an infinitely thin front hypothesis concerning finite rate crystallization process. Non-instantaneous kinetics considered consequently there no “jump at front” ice content total moisture. The zone defined as region between frozen point which vanishes. In equations, temperature, (liquid water) distribution are influenced by values these factors its velocity. For determination values, system equations obtained solved iteration method readily converges on solution. time-dependent influence characteristics presented. analysis process loamy soils was carried out variations characteristic parameters—Stefan Lewis numbers. As level increases, decreases, while become larger. With increase number, and, consequently, get case where water migration absent, to corresponds classical with front”. shown decrease time in non-instantaneous kinetic model leads flattening profiles vertical surface, approaches stage conditions occur. theoretical concepts results from analytical agreement experimental investigations. predicts satisfactorily reflects observed phenomena.