An improved void fraction model for two-phase cross-flow in horizontal tube bundles

A physically based model has been developed to predict the void fraction for upward cross-flow through horizontal tube bundles. It agrees well with experimental void fraction measurements in refrigerant 11 and air-water mixtures for a sufficiently wide range of pitch mass flux, quality and P/D ratios. It has also shown improved predictive capability for adiabatic air-water and diabatic R-113 cross-flows than the void fraction models developed by other researchers. The analysis performed also shows plausible applicability of the void fraction model to steam-water data. The present void fraction model will allow researchers and designers to obtain better estimates of void fraction in the shell side flow in applications such as kettle reboilers and the U-bend region of nuclear steam generators than with the customarily used homogeneous equilibrium model. This will result in better estimates of average fluid density and average velocity of two-phase upward cross-flow through horizontal tube bundles. (C) 2000 Elsevier Science Ltd. Ail rights reserved.