Effect of the liquid entrainment on the predicted pressure drop in vertical flow‐boiling

Abstract

Flow boiling in a vertical uniformly heated tube has been modelled employing the drift flux and two‐fluid formulations. The governing equations are solved numerically and the results presented in the form of pressure drop versus mass flux curves are compared to previously obtained experimental results. The effect of the entrained liquid fraction at the transition from churn‐turbulent to annular flow when a switch from the drift flux model to the two‐fluid formulation is made is shown to affect the results and could improve the pressure drop predictions.