ISSN Online: 2377-424X
International Heat Transfer Conference 12
Nonlinear stability analysis for a natural circulation boiling channel based on drift flux model with consideration of subcooled boiling and flow pattern change
Аннотация
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.