The onset of gas pull-through during dual discharge from a stratified two-phase region: Theoretical analysis

Abstract

A theoretical analysis for the onset of gas pull-through (entrainment) during discharge from a stratified two-phase region through two vertically aligned side branches has been developed in this paper. Initially, a simplified point-sink model was developed, which was then followed by the acquisition of a more accurate finite-branch model. The prediction of the critical height at the onset of gas entrainment was found to be a function of the corresponding Froude number of each branch (Fr1 and Fr2), as well as the vertical distance between the centerlines of the two branches (L/d). The predicted values of the critical height were found to be consistent with the corresponding experimental data for different values of Fr1, Fr2 and L/d. From the basis of the present models, it was found that by increasing the flow through the lower branch, the critical height increases for all values of Fr1 and L/d. Furthermore, by increasing the vertical distance between the two branches, the effect of the lower branch on the determination of the critical height was decreased.