Effect of Pressure on Two-Phase Stratified Flow Modeling

Abstract

This paper reviews the use of the single-pressure model in two-phase flow modeling in previous literature, and develops and demonstrates the equations for the two-pressure model. Many of the models investigated previously suffer from an inability to achieve convergence and consistent results because they have complex characteristic values. Two different model specifications -single-pressure (ill-posed condition) and two-pressure (well-posed condition) are considered in this paper. Pressure effect was taken into account for both models. The models discussed in this paper were developed for the case of a transient two-phase air-water stratified flow in a horizontal duct. Terms that induce physical viscosity like surface tension, viscous stress, etc., were not included in the models. Both models were applied to the Kelvin-Helmholtz (K-H) instability case and the equations were solved numerically. The results showed that the two-phase two-pressure flow model pioneered by Ransom and Hicks overcomes the ill-posed condition. Convergence and consistence of results, which cannot be obtained by the ill-posed models, are established using the well-posed two-pressure model.

Surface tension effect on stability of two-phase stratified flow

“…11. It should be noted that the numerical method which has been used by Ansari (2004) for the 5E2P model is the same as in the present work (the 5E2P model is explained by Ransom and Hicks (1984)).…”