17H-22 |
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S. S. R. GEEDIPALLI and A. K. Datta. Dept. of Biological & Environmental Engineering, Cornell Univ., 175 Riley-Robb Hall, Ithaca, NY 14853-5701 Combination microwave and hot air (or infrared) heating can be a successful means to combine the benefits of each mode of heating and provide customized heating profiles needed to obtain the desired quality of a prepared food in the shortest possible time. Several complex phenomena, related properties and their interplay are involved in such a combination heating process. Design of such novel processes requires careful study of the effect of the coupling of the modes on heating rates and uniformity. The objective of this work is to use an engineering fundamentals-based approach to obtain the optimum combination of heating modes that can deliver certain uniformity and speed of heating. Electromagnetic field inside the food in a microwave cavity was solved to obtain the power generated inside the food, which is then coupled in a thermal simulation model to obtain temperatures. For combining with infrared, a detailed radiative heat transfer model was used to obtain surface heat flux. To validate the simulation results, experiments were done in combination microwave-jet impingement and microwave-infrared ovens. Temperatures were measured using fiber optic probes. Surface heat transfer coefficient in jet impingement heating and surface heat flux in Infrared heating were measured using heat flux sensors. The results from the model match favorably with the measured values for temperatures below 550C. The results show very definitely that combination heating leads to more uniform heating, without compromising the speed or convenience. Food heated in a Combination Jet Impingement / Microwave Oven is 30 to 45% more uniform than that heated only in a Microwave Oven. This uniformity was obtained in spite of cooking food at about double the microwave cooking rate. It is the first comprehensive engineering study of such combination heating processes that should help the food industry and the consumer benefit from this novel technology.
Session 17H, Food Engineering: Thermal processes
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