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ANALYSIS OF HEAT AND MASS TRANSFER DURING FROST FORMATION ON FIN-AND-TUBE HEAT EXCHANGERS
Kristian Lenić
; Faculty of Engineering, University of Rijeka, Rijeka, Croatia
Abstract
In the dissertation a numerical and experimental heat and mass transfer analysis of frost layer formation on fin-and-tube heat exchangers have been presented. A mathematical model and computer program for transient two-dimensional numerical solving of mentioned physical problem have been developed. As numerical solving results the frost growth rates, temperatures, humidity and velocity distributions in the air sub-domain, as well as temperatures and density distributions in the frost sub-domain have been gained. For the purpose of mathematical model and computer program validation, the experimental line has been set up on which experimental investigations have been performed. An analysis of frost formation impact on heat transfer conditions and impact of increased thermal resistance on heat exchanger performance has been carried out. Practical solutions and algorithm for optimal control of appliances have been given. The developed algorithm enables the determination of optimal cycle duration and adaptive determination of defrost cycle initiation time depending on frosting conditions of the heat exchanger.
Keywords
frost layer formation; fin-and-tube heat exchanger; heat and mass transfer
Hrčak ID:
28412
URI
Publication date:
27.12.2006.
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