Modeling of droplet entrainment in co-current annular two-phase flow: A new approach

Entrainment fraction is one of the key parameters in many applications including wellbore and flow line design, separator design and wellbore loading and many others. Its prediction is important for the estimation of pressure drop, liquid holdup and dry-out in annular flow. The available and widely used maximum fraction of entrainment models have failed to predict the maximum entrainment fraction at low liquid Reynolds number.In this paper a new methodology of modeling the entrainment fraction, containing only two constants, is proposed. The proposed new methodology and procedure was found to predict the experimental data available in the literature very well. Furthermore, an equation for the maximum fraction of entrainment was developed. The proposed maximum entrainment fraction equation predicted more accurately than the equations found in the literature.

► A new methodology of modeling the entrainment fraction is proposed.
► A new equation for the maximum fraction of entrainment in annular flow was developed.
► The proposed maximum entrainment fraction equation predicted better than others.
► Model of Sawant et al. (2009) for maximum entrainment fraction does not predict very well.
► Model of Pan and Hanratty, 2002a and Pan and Hanratty, 2002b for maximum entrainment fraction does not predict very well.