ARTICLE:

• TWO-PHASE FLOW INSTABILITIES IN HORIZONTAL AND VERTICAL IN - TUBE FLOW BOILING SYSTEMS  download article

Sadik Kakac
Department of Mechanical Engineering, University of Miami, P.O. Box 248294 - Coral Gables, Florida - 33124-0624 - USA

Claudia O. Gavrilescu
Department of Mechanical Engineering, University of Miami Coral Gables, FL 33124, USA

ABSTRACT

In this work, two-phase flow instabilities in boiling vertical and horizontal systems are presented. in the first phase of this study, the experimental results of density-wave type oscillations in a single channel, forced convection boiling upflow system using water are given. The limiting heat flux and quality of the onset of density-wave type oscillations were determined; their dependence on system pressure, mass flux, inlet subcooling and exit restriction was found and presented graphically. Also a correlation is formulated for the prediction of the limiting heat flux and quality of density-wave type oscillations. The second phase of this study involves the prediction of the low frequency oscillations in a horizontal system using R-11. The steady-state system pressure-drop characteristics are determined by a numerical solution of the governing equations as derived from the Drift-Flux model. The transient characteristics of the two-phase flow are obtained for various parameters. The numerical solutions are determined using an explicit finite difference scheme. A satisfactory agreement between the theory and experiments is obtained.

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