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International Heat Transfer Conference 13

ISBN Imprimir: 1-56700-226-9 (CD)
ISBN En Línea: 1-56700-225-0

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

DOI: 10.1615/IHTC13.p28.100
page 12

Yoshio Utaka
Yokohama National University, Department of Mechanical Engineering, Tokyo Institute of Technology 2-12-1 0-okayama, Meguro-ku Tokyo 152 JAPAN; School of Mechanical Engineering, Tianjin University, 135 Ya Guan Rd. Tianjin Haihe Education Park, Jinnan District, Tianjin300350, China; Key Laboratory of Efficient Utilization of Low and Medium Grade Energy (Tianjin University), Ministry of Education, China

S. Okuda
Honda Engineering Co. Ltd., Haga-gun, Tochigi, Japan

Yutaka Tasaki
Technology Research Laboratory No. 2, Nissan Research Center, Nissan Motor Co., Ltd., 1, Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523, Japan

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.

IHTC-13 Digital Library

Measurement of fluid temperature with an arrangement of three thermocouples FLOW BOILING OF A HIGHLY VISCOUS POLYMER SOLUTION