Computer simulation of combined microwave and water heating processes for packaged foods using finite difference time domain method

A microwave sterilization system was developed at Washington State University (WSU) that allows development of High-Temperature-Short-Time (HTST) processes for packaged foods. This system combines microwave and hot water heating. A major challenge of this novel technique is possible non-uniform heating created from the non-even electromagnetic distribution. The objective of this research is to develop an efficient and reliable numeric model to simulate the microwave sterilization process and provide the prediction of temperature profiles and distributions. Various conditions such as different dielectric properties, different physical configurations and different operation parameters were investigated to study their influences on heating uniformity in packaged foods. The simulation results were applied to predict system performance and obtain parameters for process optimization.;Before the numeric model can be applied to analyze and optimize the system, it has to be validated. In this study, the simulation model was validated by comparing the numeric results with experimental measurements under both stationary and moving conditions. The heating patterns were measured by using a computer vision method developed by the microwave sterilization group at WSU. This method uses a chemical marker M-2 as an indicator of heat intensity inside the food packages, the marker intensity is converted to colour image for visualization purpose.;The numeric model was then used to investigate the heating patterns under various conditions to improve the heating uniformity and reduce heating time. A sophisticate algorithm was developed to provide the set of operational parameters or physical configurations so that optimal performance can be achieved. Finally, future researches were suggested.