2-FLUID MODELING OF INVERTED ANNULAR FILM BOILING

A two-fluid model was developed to predict the wall temperature of a t ube during inverted-annular film-boiling (IAFB). This model correctly accounts for the effects of how variables such as mass flux, inlet sub cooling, heat flux and pressure. The relations for shear stress and he at transfer rates are the major components in this model. A unique met hodology is utilized to derive these relations. Comparisons between th e two-fluid model predictions and experimental data from four fluids ( water, Freon-12, Freon-22, and Freon-134a) show good agreement over a wide range of flow conditions. The comparisons resulted in overall roo t-mean-square (RMS) errors of 14.90, 5.67, 6.58 and 6.19% with the dat a of water, Freon-12, Freon-22 and Freon-134a, respectively. The model shows better performance than other IAFB prediction methods that were assessed during the course of this study. (C) 1997 Elsevier Science L td.