Analysis of the Flow Reversal in Natural-Circulation Boiler

概要

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Flow reversal phenomena in natural-circulation boilers are studied analytically according to both the homogeneous-flow model and the slip-flow model. In the latter model Thom's pressure drop correlation is used. The pressure drop between the upper steam-water drum and the lower header is assumed not to be affected by inception of reverse flow in an evaporator tube which will be analyzed later.<BR>The mechanism of flow reversal is examined through analysis of the static flow characteristics of the evaporator tube in the non-dimensional form. Some important dimensionless parameters are introduced and their effects on inception of reverse flow are studied.<BR>It was found that the criterion of flow reversal is correlated practically with only three dimensionless parameters. Finally, an approximate method to predict flow reversal is put forward.
日本混相流学会の論文