Air drying of food and biological materials - Modified Biot and Lewis number analysis

In this paper, a modified Biol and Lewis number analysis of air-drying of food and biological objects with small sizes has been carried out. It has been shown that the evaporative action broadens the range of the application of the conventional Biot assessment for uniform temperature approach. For evaluating whether heat or mass transfer is the limiting process for drying, the article has preliminarily demonstrated that the inclusion of the sorption characteristics of the material being dried in the calculation of the effective diffusivity for water vapor predicts larger Lewis numbers (greater than unity). Sample calculations are given in this article based on previous laboratory results.