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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Annular Two-Phase Heat-Transfer in Vertical Upward and Downward Flows

Get access (open in a dialog) DOI: 10.1615/IHTC12.1540
6 pages

Abstract

Two-phase annular flows occur in many industrial applications including boilers, nuclear plants, oil and gas pipelines, and active heat transport systems. In the past, very little research has been done in the vertical downward flow orientation. The results discussed here examine the effects of changing the direction of the gravity vector (+1g upward flow, -1g downward flow) on the rate of heat transfer in two-phase annular flows of a mixture of air and water. The results show a measurable effect as a result of changing the direction of the gravity vector. The downward flow heat transfer values are lower than the corresponding values for upward flow. While the difference between the upward and downward heat transfer values is small, the results confirm the strong effect of gravity in terms of altering the flow regime and hence the heat transfer rates in annular flow.