Core-Annular Oil/Water Flow: The Turbulent-Lubricating-Film Model and Measurements in a 2-in. Pipe Loop

Abstract

Core-flow tests with a 3000 mPa.s fuel oil in a 2-inch test facility have revealed important information on the amplitudes and lengths of waves at the oil/water interface. The wavelengths vary considerably with water fraction and oil velocity. Moreover, the flow in the water annulus is turbulent. A previously developed theoretical model for steady core-annular flow in pipes has been extended by incorporating the effect of turbulence in the water film surrounding the oil core. Core-flow pressure gradients predicted by the adapted model coincide very well with measurements provided that actual wave amplitudes and wavelengths observed during these tests are used as input data.

The influence of abruptly variable cross-section on oil core eccentricity and flow characteristics during viscous oil-water horizontal flow

“…As far as liquid-liquid flows are concerned, a certain number of models dealing with core annular flow in horizontal pipes have been presented in the literature. Among them, the empirical correlations of Arney et al (1993), Oliemans et al (1987) and the mechanistic models of Brauner (1998), Ullmann and Brauner (2004), Colombo et al (2017) for oil-water flow can be cited. The basic theory underlying these models, however, assumed axis-symmetric flow of oil-water mixture and did not consider explicitly the influence of core eccentricity.…”

“…The vast majority of the related published work deals with viscous oilwater mixture within straight horizontal pipelines. During the past years, we can mention the works by Charles et al (1961), Ooms et al (1984), Oliemans et al (1987), Arney et al (1993), Bannwart et al (2004), Grassi et al (2008), Sotgia et al (2008), Colombo et al (2012).…”

Flow patterns and pressure gradient correlation for oil–water core–annular flow in horizontal pipes

“…Totally 110 groups of CAF pressure loss data from literature (Oliemans et al, 1985;Grassi et al, 2008;Sotgia et al, 2008;Al-Wahaibi et al, 2014) and 114 groups of data in our study were used to evaluate the prediction precision of pressure loss models. The experimental data involved the oil viscosity from 12 to 3000 mPa•s, pipe diameter from 14.5 to 50.0 mm, the oil superficial velocity from 0.20 to 2.37 m/s, and the water superficial velocity from 0.03 to 1.68 m/s.…”

“…Moreover, the adaptability of the model to the experiment condition of the steel pipe should also be investigated. 2014and Oliemans et al (1985).…”

Experimental Study on Pressure Loss of Horizontal Core-Annular Flow

“…1) Lubrication Model Ooms et al (10) and Oliemans et al (11) reported equations for estimating pressure gradient based on the hydraulic lubrication theory. Their equations require the wave length and amplitude of the oil core and thickness of the annular region, which are not easily obtainable.…”