Application of a Multifield Model to Reflooding of a Hot Vertical Tube: Part II—Analysis of Experimental Results

The two-fluid model equations developed for reflood calculations and discussed in Part I (Kawaji and Banerjee, 1987) are solved numerically with appropriately formulated constitutive relations to analyze the Inconel tube reflood experiments involving inverted annular and dispersed flow regimes downstream of the quench front. Constitutive relations are formulated separately for individual transfer mechanisms that are considered to be phenomenologically significant. For inverted annular flow, phasic pressure difference is incorporated into the momentum equations to predict the interfacial waves which enhance film boiling heat transfer. For dispersed flow, a size distribution of drops is considered and both single and multifield equations of motion are solved to calculate the droplet transport. Most of the important heat transfer and hydrodynamic aspects of the experimental results are predicted reasonably well, indicating the adequateness of the mechanisms considered. In particular, a wall–drop interaction heat transfer mechanism is determined to be essential in explaining the experimentally observed strong dependence of heat transfer rate on liquid volume fraction in the dispersed flow region. A sensitivity study is made to identify the weaknesses in the constitutive relations, but no single relation could be accounted for areas in need of further improvement. In comparison with the predictions of the single-field model, those of the multifield model showed improvement for some but not all experiments.