부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jfoodeng.2006.03.012 Byline: Ferruh Erdogdu (a), Maria Ferrua (b), Samrendra K. Singh (b), R. Paul Singh (b) Keywords: Air-impingement cooling; Numerical modeling of heat transfer and flow field Abstract: Production of ready-to-eat boiled eggs is a rapidly expanding process. Cooling of the boiled eggs, before peeling, is therefore a significant part of the production. Use of water immersion for cooling purposes is traditional way to accomplish a faster cooling process. However, the utilization of water brings the waste water problem with itself, and there also might be a cross-contamination problem after a longer use. Since the air-impingement processes are to produce higher heat fluxes over the product surface, cooling of boiled eggs by a slot air (24[degrees]C) impingement system (H/D of 3-jet exit to object distance over hydraulic diameter of the jet, Reynolds number of [approximately equal to]7000) was investigated in this study. Continuity, conservation of momentum and conservation of energy equations were solved using Fluent 6.0 (Lebanon, NH). In order to model the turbulent air flow, the [kappa]-I[micro] turbulence model was applied. The model results were validated by comparing them with the experimental flow (the particle image velocimetry-PIV data) and temperature data (obtained at different locations of the egg). Different cooling conditions (0[degrees]C impinged air and 0[degrees]C water-for immersion type of cooling) were also simulated, and the results were compared with each other to show the effectiveness of the air-impingement systems. The results of this study showed the potential of air-impingement systems for an effective use in cooling of boiled eggs. However, it would also be valuable to show the effects of different impingement parameters (e.g., H/D, d/D, different nozzle arrangements and effects of higher Reynolds numbers) to compare the results with different cooling systems (e.g., use of spray water). Author Affiliation: (a) Department of Food Engineering (Gida Muh. Bolumu), University of Mersin, 33343 Ciftlikkoy-Mersin, Turkey (b) Department of Biological and Agricultural Engineering, University of California, Davis, 95616 Davis, CA, USA Article History: Received 30 October 2005; Accepted 9 March 2006