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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

CONFIGURATION OF MICRO-LAYER IN THIN-GAPS IN BOILING HEAT TRANSFER

Get access (open in a dialog) DOI: 10.1615/IHTC13.p28.100
12 pages

Sinopsis

A compact vapor generator with high density vapor generation and high response is required to feed vapor for a reformer type fuel cell vehicle. A plate type heat exchanging device, in which many units with thin gaps are laminated together, is assumed to be one solution to achieve high performance. To design such a mini-channel vapor generator, it is basically essential to clarify the mechanisms and characteristics of boiling heat transfer.
In this study, experimental measurement of the micro-layer thickness and investigation of its configuration was performed to elucidate the mechanism and characteristics of boiling heat transfer in mini-channels. The laser extinction method was effective for measuring a thin liquid film thickness of micron-order with high response and without contact.
The variations of micro-layer thickness were measured for the channel gap sizes of 0.3 and 0.15 mm. The gap size and the rate of bubble growth mainly affect the micro-layer thickness. The analysis of the results of micro-layer thickness measurement revealed the distributions of the initial micro-layer thickness on the surface for a gap size of 0.3 mm. It was clarified that the thickness of the micro-layer was very thin near the bubble incipient site and increased with increasing distance.