Finite Element Modeling of Coupled Heat and Mass Transfer of a Single Maize Kernel Based on Water Potential Using COMSOL Multiphysics Simulation

A.J. Kovács, E. Lakatos, G. Milics, and M. Neményi
University of West Hungary, Institute of Biosystems Engineering, Mosonmagyarovar, Hungary

Finite element modeling of agricultural materials is very often used for describing physical processes. However, exact physical measurements are needed as input parameters for the models. Knowing the driving forces (potentials) during heat and mass transfers is necessary for an accurate model. Water potential gradients as the driving force are used in contrast with the conventional practice (where moisture gradients were used) for modeling of mass transfer in a single maize kernel. For this the water potential values (curves) of the materials had to be determined, therefore measurements of the different particles (pericarp or skin, endosperm and germ) of a grain were carried out by using pressure plate method. This method was adapted from soil science where measurements of pF values (soil water potential) are well known. COMSOL Multiphysics software is used for the calculation the coupled heat and mass transfer in the inhomogeneous irregular shaped composite biological material namely maize kernel. The results give realistic temperature and moisture migration within the grain that were verified by thermography and magnetic resonance imaging.