Hydrodynamic Study Using CFD Simulations in a Horizontal Two-Phase Flow Through Sudden Contraction

Ibtissem Belgacem

doi:10.11648/j.ajmie.20170201.12

Abstract

Two-phase flows are encountered in a wide range of industrial application. In the present work, two-phase computational fluid dynamics (CFD) calculations, using Eulerian–Eulerian model and commercial CFD package FLUENT 6.3, were employed to calculate pressure drops caused by abrupt flow area contraction in small circular pipes for two-phase flow of air and water mixtures at room temperature and near atmospheric pressure. The pressure drop is determined by extrapolating the computed pressure profiles upstream and downstream of the contraction. Variables studied include: gas and liquid velocities, and pipe contraction ratio. The numerical results were validated against experimental data from the literature and are found to be in good agreement. Our findings could be useful in designing pipeline.

Highlights

Liquid-gas two-phase flows are widely encountered in industrial applications including chemical processes, petroleum engineering and energy manufacturing units systems
On the other hand Abdelall et al [7] pointed out that their recorded pressure drops, caused by abrupt flow area expansion and contraction, were lower than those predicted by the homogeneous flow model, a significant velocity slip ratio existed at the vicinity of the flow area change
Many authors report that the two phase flow has the same characteristics as those in single phase-flow, Assuming incompressible gas and liquid phases, and assuming x and α remained constant across the sudden contraction, following these assumptions, the total pressure drop across a sudden contraction can be estimated from Abdelall et al [7] (Zivi model [24])

Summary

Introduction

Liquid-gas two-phase flows are widely encountered in industrial applications including chemical processes, petroleum engineering and energy manufacturing units systems. To ensure the distribution of the fluids in the industrial hydraulic installations, these systems often exhibit complex geometry comprising singularities such as expansions, contractions, orifices, bends etc Among these singularities, the abrupt contraction is relevant in many applications and has significant effects, on the two-phase flow behavior as well flow pattern, over manifolds the pipe diameter and subsequently the resulting pressure drop. Experimental pressure drops for steam water mixtures flowing through sudden contraction were reported by Geiger [3] for area ratios of 0.398, 0.253 and 0.144, as well as by McGee [4] for area ratios of (0.608 and 0.546) In both cases the homogeneous model gives the best predictions of the data. Additional experimental work was reported by Chalfi et al [8] for Rel

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Conclusion