A two-fluid model for stratified flows with curved interfaces

This study is motivated by the need to develop a practical tool for predicting the interface shape in stratified flow of a general two-fluid system. A configuration of a curved interface is considered. A two-fluid model is used to solve the momentum equations for a variable interface curvature. Energy considerations provide a closure relation for the interface curvature. The analysis identifies all the input dimensionless parameters which determine the solution for the stratified flow pattern. When these are given; a complete solution of the problem is obtained, including the interface shape, in situ hold-up and pressure drop. The validity-of the two-fluid model is evaluated by comparing its prediction with-available experimental data and;with the results of exact analytical solutions for laminar flows with curved interfaces. Thus, the conventional two-fluid model has been extended to tackle stratified flow with curved interfaces and various flow regimes, in which case analytical solutions are complicated and restricted to laminar flows. (C) 1998 Elsevier Science Ltd. All rights reserved.