An Assessment of Void Fraction Predicting Methods for Gas–Liquid Two-Phase Flow in an Annulus

Abstract

Gas void fraction plays an important role in the calculation of several multiphase flow parameters. The prediction of a void fraction for gas–liquid two-phase flow in an annulus is needed by many design practices. In the present work, void fraction correlations based on the homogeneous method, slip-ratio method, and drift-flux method are reviewed, and a total of 24 correlations, 8 for each group, are collected. A database covering 1136 experimental data points of void fractions from 0.009 to 0.972 in an annulus is developed, with the range of hydraulic diameters from 0.002 to 0.057 m, and the pipe inclinations from horizontal to vertical. The 24 correlations are tested against the entire database to evaluate their abilities in predicting the void fraction of two-phase flow in annuli. It is found that no correlation studied here provides satisfactory agreement with the whole database, and many correlations show good symmetry but with poor concentration. A void fraction correlation for flow in annuli is proposed based on the drift-flux model with a new equation for the distribution parameter. Comparison of the predicted value with the experimental data shows good agreement.

Multiphase Transportation, Conversion, & Utilization of Energy in Chemical Engineering: A Special Issue for MTCUE-2022

“…Gas void fraction plays an important role in calculations of several multiphase flow parameters. A void fraction correlation for flow in annuli was proposed based on the drift-flux model with a new equation for the distribution parameter . Furthermore, heat and mass transfer from droplets to gas phase by evaporation was modeled, and a self-similar description of the transport equations for concentration of the vapor phase from boundary-layer theory was derived .…”