Abstract

This study included air drying of a single le kernel of fruits (apple, apricot or grape) which is taken as a sphere. Convective heat and mass transfer takes place between the sample surface and its drying environment; while, unsteady heat conduction and moisture diffusion take place within the drying body without phase change for liquid (evaporation occurs at the surface only). The mass, energy conservation equations was solved by using the finite difference technique. A set of empirical correlations have been employed to determine the product properties which assumed to be changed during drying process like (thermal conductivity, specific heat and coefficient of moisture diffusion) and other properties was assumed to be constant through the process as (the coefficients of heat and mass transfer and the density). The results showed that the product temperature is increased and its moisture content will decrease during the drying process. The numerical results were compared with experimental results and showed good agreement.