Simulation of Intermittent Flow Development in a Horizontal Pipe

Abstract

In this study, detailed three-dimensional (3D) numerical simulations of intermittent multiphase flows were carried out to investigate the slug initiation process and various features of intermittent flows inside a horizontal pipe. Air and water are used as working fluids. The domain used for simulations is a 14.4 m long pipe with 54 mm inner diameter. The volume of fluid (VOF) model was used to capture the air/water interface and its temporal evolution. Using the developed computational fluid dynamics (CFD) model, the slug formation and propagation along horizontal circular pipe were successfully predicted and studied comprehensively. Slug length and the frequency of slug formation, as two main features of intermittent flow, were used to validate the model against experimental results and available correlations in the literature. Three-dimensional numerical simulation of intermittent flow proved to be a powerful tool in tackling limitations of experiments and providing detailed data about various features of the intermittent flow. The effect of gas and liquid superficial velocities on the liquid slug and elongated bubble length was explored. Moreover, the study revealed new findings related to the elongated bubble shape and velocity field in the slug unit.

The effect of air velocity on slugs in a confined channel

“…The results obtained using the VOF model agree well with the experimental data, especially for low gas velocities. Other research [34]- [36], [41] examined the ability of numerical models to predict the development and characteristics of intermittent flows (slug flow and plug flow). Nasrfard et al [34] simulated two-phase flow in a 14.4 m long pipe with an inside diameter of 54 mm.…”

“…Other research [34]- [36], [41] examined the ability of numerical models to predict the development and characteristics of intermittent flows (slug flow and plug flow). Nasrfard et al [34] simulated two-phase flow in a 14.4 m long pipe with an inside diameter of 54 mm. They concluded that using the VOF model, the formation and propagation of the slug flow regime along horizontal circular pipes is successfully described and validated against the experimental results.…”