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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

ON THE DRYOUT OF THIN LIQUID FILM NEAR A FLOW OBSTACLE IN BOILING VERTICAL UPWARD FLOW

Get access (open in a dialog) DOI: 10.1615/IHTC13.p28.300
10 pages

Resumo

If a flow obstacle such as a spacer is placed in a boiling two-phase flow within a channel, the temperature on the surface of the heating tube is severely affected by the existence of the spacer. Under certain conditions, a spacer has a cooling effect, and under other conditions, the spacer causes dryout of the cooling water film on the heating surface. The burnout mechanism, which always occurs upstream of a spacer, however, remains unclear.
In a previous paper (Fukano et al. (2002)), we reported that the disturbance wave has a significant effect on dryout and burnout occurrence and that a spacer greatly affects the behavior of the liquid film downstream of the spacer. In the present paper, we will discuss in detail the influence of a spacer on the heat transfer and film thickness characteristics downstream of a spacer. Moreover, at the end of this paper, we will propose a new burnout occurrence model in consideration of the unsteady nature of two-phase flow.