Spatial Distribution of Oil and Water in Horizontal Pipe Flow

Abstract

In this paper we report a series of experiments to quantify the spatial distribution and identify the flow pattern of liquid-liquid flow in a horizontal 25.4-mm ͑nominal 1-in.͒ tube. Experimental results are presented for kerosene ͑EXXOL D80͒ and tap water at room temperature. Two different measurement techniques ͑a high frequency impedance probe and a gamma densitometer system͒ were applied for measuring the volume fraction distribution across the tube and to obtain tomographic results for phase distribution. The use of the gamma densitometer system to obtain the tomographic results in liquid-liquid cocurrent flow is believed to be the first in this field. These methods are more precise than other techniques such as visualization and help to distinguish certain differences in flow patterns for different superficial velocities and liquid fractions. The two sets of measurements were compared and it was concluded that the gamma densitometer system was a more reliable method by which to measure the volume fraction. Two important phenomena in liquid-liquid flow were observed: oil encapsulation by water at low mixture velocity and droplets concentrated at the center of the pipe in the dispersed flow regime. Some possible explanations are given regarding these phenomena.

Phase Inversion Correlations Analysis for Oil–Water Flow in Horizontal Pipes

“…Even though the prediction of phase inversion referred most of the times to a single point, some researchers have indicated the existence of an ambivalent region, or a range of phase fractions, over which either phase can be continuous. This is supported by various authors who have indicated that phase inversion may not co-occur across the whole pipe, leading to transitional regions where phase inversion begins and completes. ,− …”

“…The effect of different parameters such as viscosity, pressure gradient, flow velocity, phase distribution, pipe diameter and material, wettability, droplet size, and interfacial tension on phase inversion has been studied for liquid–liquid flow on pipelines . Authors like Martinez et al, Angeli, Nädler and Mewes, and Soleimani et al have found that significant changes in pressure gradient are due to phase inversion; however, changes are still not accurately attributed. An example of this issue is presented in experimental studies by Ioannou et al , they found, using as fluids Exxsol D80 and water, that phase inversion occurs at the peak of the pressure gradient, although as already said, this result has not always been obtained.…”

Development of Next Generation Multiphase Pipe Flow Prediction Tools

“…In most of the reported studies, identification of the flow pattern is based on visual observations, photographic/video techniques, or abrupt changes in the average system pressure drop (Brauner, 2002). Only recent studies have used tools such as conductivity probes or sampling probes (Soleimani et al, 1999); some others include isokinetic probes, impedance probes and gamma densitometers.…”

Two Phase Flow Experimental Detection Method and CFD Models – A Review

“…(Nadler and Mewes, 1997) [24], used visual observation to study stratified flow, stratified with mixture, desperation of water in oil and oil in water, another combination of water and oil used. Also (Soleimani, 1999) [25], investigated by using visual observation, gamma densitometer and high frequency impedance, to predict pressure gradient and phase distribution of different flow patterns (stratified, stratified wavy and stratified with mixture). (Rodriguez and Oliemans (2006) [26], investigated oil/water two-phase flow experiments by using high speed camera for detection of flow pattern and Gamma ray densitometry.…”