111-7 |
|
D. KOCER and M. V. Karwe. Dept. of Food Science, Rutgers, The State Univ. of New Jersey, 65 Dudley Rd., New Brunswick, NJ 08901-8520 Jet impingement oven is a unique type of convection oven in which high velocity jets of hot air impinge on a food product. It has the advantages of faster and more uniform surface heat transfer as well as higher rate of surface moisture removal, which results in quick crust development and color formation, while keeping the interior regions of the product moist and succulent. To optimize the design of the oven and understand the baking process, we need to study the flow and temperature field in these ovens. The objective of this research was to simulate the flow field and heat transfer in a multiple jet impingement oven. Using mathematical model for turbulent flow of hot air and wall-to-wall and wall-to-product radiation heat transfer, numerical simulations were carried out in a jet impingement oven (Fujimak SuperJet, Enersyst). Natural convection effects were neglected. The oven has 31 jets (1 cm diameter) that impinge on the product from top and 33 jets (1 cm diameter) from the bottom. The oven cavity dimensions are 28.5 cm wide by 28 cm deep and 15.5 cm height. 3 D flow and temperature fields, particle traces for flow of hot jets were obtained using a commercial CFD software (Fluent, NH). Numerical simulations clearly showed developing flow and temperature fields that were not symmetric because of the inherent design of the oven. As expected, it took longer for the temperature field to reach steady state conditions. From the predicted flow and temperature fields, distribution of local heat transfer coefficient on a product located in the oven cavity were calculated and compared with the experimental data. This study has shown that numerical simulation can be effectively used to simulate flow field and heat transfer during hot air jet impingement processing.
Session 111, Food Engineering: Modeling heat transfer and microbial inactivation
|