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ISSN Online: 2377-424X

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

Nonlinear stability analysis for a natural circulation boiling channel based on drift flux model with consideration of subcooled boiling and flow pattern change

Get access (open in a dialog) DOI: 10.1615/IHTC12.430
6 pages

Abstract

The present study investigates the nonlinear dynamics of a natural circulation boiling channel based on the drift flux two-phase flow model, which may consider subcooled boiling as well as the relative motion between two phases. The effect of two-phase flow pattern on the nonlinear dynamics was taken into account through the void fraction distribution parameter and drift velocity. The set of partial differential governing equations are integrated analytically based on the Galerkin nodal approximation method with MAPLE V r5. Such a nodal approximation method transforms the original set of partial differential balance equations into a set of nonlinear ordinary differential equations that can readily be solved numerically. The model is able to predict the stability boundary as well as instability behavior in the unstable region. It is found that the two-phase flow pattern variations follow closely with the inlet velocity. Moreover,under the conditions of two steady-state solutions, the system may oscillate irregularly between two possible solutions.