Coupled heat and mass transfer with one sublimation moving interface and freezing zone

Abstract

The present work discusses coupled heat and mass transfer during freeze-drying of a wet substance where sublimation and freezing occur concurrently. The formulation is based upon the Luikov system and the fact that in the wetted region, heat and mass transfer is due to temperature and concentration gradients; in the frozen region, heat transfer is due to temperature gradients; and in the dried region, vapor flow results from both moisture and pressure gradients. An exact solution of the problem is obtained and effects of several parameters on freezing and sublimation have been observed and discussed in detail. The whole analysis is presented in dimensionless form. Numerical examples of particular interest have been studied and discussed in detail. © 2015 by Begell House, Inc.