ISSN Online: 2377-424X
ISBN CD: 1-56700-226-9
ISBN Online: 1-56700-225-0
International Heat Transfer Conference 13
CONFIGURATION OF MICRO-LAYER IN THIN-GAPS IN BOILING HEAT TRANSFER
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.
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.