Flow patterns observed in near-horizontal oil-water two-phase flows are quite different from those in gas-liquid flows. Experience with gas-liquid flows suggests that the mechanisms governing the flow behavior are flow-pattern dependent. However, little attention has been given to modeling flow patterns observed only in liquid-liquid systems. Such flow patterns include an oil-in-water dispersion flowing on top of a water layer and the simultaneous flow of dispersions of water-in-oil and oil-in-water as separate layers.
A new mechanistic model is developed for one such flow pattern in horizontal and near-horizontal pipelines. The model combined the two-fluid model used for stratified flows with the homogeneous model used for dispersed flows. This paper presents that model, and shows that the new model can predict the pressure gradient as well as the holdup. The model results are compared with those from two other models, the stratified flow model and the homogeneous model. The new model predictions are also compared with available experimental data.