FINITE-ELEMENT MODELING OF HEAT AND MASS-TRANSFER IN FOOD MATERIALS DURING MICROWAVE-HEATING - MODEL DEVELOPMENT AND VALIDATION

A three-dimensional finite element model (FEM) was developed to predic t temperature and moisture distributions in food materials during micr owave heating. The FEM was tested with analytical solutions and commer cial software (TWODEPEP, ANSYS) calculated values. The FEM predictions compared favorably with analytical solutions (within 0.066% of maximu m temperature) and values calculated from commercial softwares (within 0.14% of maximum temperature). The three-dimensional FEM was also ver ified using experimental data from microwave oven heated cylinder- and slab-shaped potato specimens. A fluoroptic temperature measurement sy stem and the near infrared (NIR) technique were used to measure temper ature and moisture distributions, respectively. The FEM predicted temp erature in potato samples agreed with measured results. The absolute m aximum difference for slab geometry after 60 s of heating was 8.1-degr ees-C (or relative difference of 15.5% from the measured value), where as, for the cylindrical geometry, it was 8.7-degrees-C (or relative di fference of 11.4%). The absolute moisture differences after 60 s of he ating between FEM predictions and measured values for potato slab and cylinder were within 1.97% wet basis (or relative difference of 2.4%) and 1.85% wet basis (or relative difference of 2.1%), respectively.