Coupled heat and mass transport in unsteady sublimation drying

Abstract

AbstractSublimation drying is analyzed by considering coupled heat and mass transport at the ice‐vapor interface. Since, the typical model of sublimation drying assumes a pseudo steady state heat transport limited process, these assumptions are critically analyzed to determine whether they are the cause of some of the limitations of the simplified model. It is shown that although total drying times can be substantially increased if there is heat leakage into the ice core and coupled heat and mass transport, this is not a problem in the conventional sublimation drying of foods. However, the results indicate that consideration of both coupled transport and heat leakage into the core result in time‐varying ice temperatures which could exceed the triple point. In addition, the application of this analysis to the analogous heterogeneous chemical reaction problem is pointed out and appropriate conclusions can be drawn by inference.