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 AS  Vol.3 No.4 , July 2012
Diffusion models for the description of seedless grape drying using analytical and numerical solutions
Abstract: This article compares diffusion models used to describe seedless grape drying at low temperature. The models were analyzed, assuming the following characteristics of the drying process: boundary conditions of the first and the third kind; constant and variable volume, V; constant and variable effective mass diffusivity, D; constant convective mass transfer coefficient, h. Solutions of the diffusion equation (analytical and numerical) were used to determine D and h for experimental data of seedless grape drying. Comparison of simulations of drying kinetics indicates that the best model should consider: 1) shrinkage; 2) convective boundary condition; 3) variable effective mass diffusivity. For the analyzed experimental dataset, the best function to represent the effective mass diffusivity is a hyperbolic cosine. In this case, the statistical indicators of the simulation can be considered excellent (the determination coefficient is R2 = 0.9999 and the chi-square is χ2 = 3.241 × 10–4).
Cite this paper: Silva, W. , Silva e Silva, C. , Precker, J. , Gomes, J. , Nascimento, P. and Silva, L. (2012) Diffusion models for the description of seedless grape drying using analytical and numerical solutions. Agricultural Sciences, 3, 545-556. doi: 10.4236/as.2012.34065.
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