Three-dimensional TLM models for water diffusion in white rice

Abstract

Two, three-dimensional TLM models for water diffusion in white rice were developed. The first model consists of a three-dimensional orthogonal TLM grid with constant mesh size, the second of a two-dimensional orthogonal TLM grid with constant mesh size, using axisymmetric elements. The average mass diffusivities at 30, 40 and 50°C were estimated to be 0·875, 1·000 and 1·181 × 10 −10m 2 s −1 with the first model and 0·958, 1·139 and 1·319 × 10 −10m 2 s −1 with the second model. On the basis of an Arrhenius-type equation, the activation energy for water diffusion in white rice was calculated as 12·19 kJ mol −1 and 13·03 kJ mol −1 respectively for the first and the second model.