Numerical simulation of microwave thawing of solid foods

L.A. CAMPAÑONE; ZARITZKY N

Brasil

Conferencia; CIGR - International Conference of Agricultural Engineering 2008; 2008

The use of microwaves in the food industry is based on the shorter times required to increase foodstuffs temperature when compared to conventional thawing methods. However, there are some problems associated to temperature distribution within the products, owing to preferential absorption of electromagnetic energy by liquid water, caused by differences between its dielectric properties and those for ice ("runaway"). To analyze the behavior of food microwave thawing, a mathematical method was developed by solving the unsteady state heat and mass transfer differential equations. The model was applied to large food pieces for which Lambert´s law is valid because it leads to similar results as Maxwell equations. Thermal, transport (diffusional) and electromagnetic properties varying with temperature were used. The numerical solution was developed using an implicit finite difference method in one dimensional system and an alternating direction method in two and three-dimensions. The model was validated with data obtained in our laboratory as well as with experimental data from literature.