Abstract
Co-current two-phase simulations of gas-liquid flow with mixture velocities from 1.2 to 4.2 m/s were run in a partially eccentric annulus and compared with entirely eccentric and concentric experimental data collected at the Institute for Energy Technology in Norway. The gas-phase was sulphur hexafluoride (SF6) for all cases, while the liquid-phase was Exxsol D60 for the horizontal cases and a mixture of Exxsol D60 and Marcol 82 for the inclined case. The outer diameter of the annulus was 0.1 m for all cases, while the inner diameter was 0.05 m in the horizontal configuration and 0.04 m for the inclined configuration. The purpose of this paper is to explore the effect of the holdup fraction, mixture velocity, and interior pipe’s position on the pressure gradient and flow regime, in effect a study of the pressure gradient and holdup fraction transients. The comparisons between simulations and experiments indicate that moving the pipe from an entirely eccentric to the partially eccentric configuration has a drastic impact on the pressure gradient. In all 4 cases where the inner pipe was changed from a completely eccentric geometry in the experiments to a less eccentric configuration in the simulations, we notice an increase of 48–303% of the mean pressure gradient. Comparatively, the 4 cases where the pipe was moved from a concentric experimental configuration to a more eccentric configuration in the simulations result in less drastic pressure gradient changes. Two cases were within 22% of the experimental results for mean, maximum, and minimum pressure gradient, while the last two cases exceeded the minimum and mean pressure gradients by 25–250%, respectively. The flow regime is rarely significantly affected by a change in eccentricity; 2 out of the 8 horizontal cases indicate either a transition from wavy flow to slug flow or significantly larger waves. The most prominent and frequent discrepancies identified were altered slug and wave frequencies. The last case, a 4o inclined, partially eccentric simulation was compared to an entirely eccentric experiment and results in a 0.2 Hz increase in wave frequency, up from the experimental 0.56 Hz and a 49% increase in the mean pressure gradient.
Highlights
The modern-day study of two-phase and multiphase flow was spurred on by the discovery of oil and gas and the worldwide dependence on fossil fuels to power our cars and planes but countless other applications of everyday life.The topic of this paper, which is two-phase flow within an annulus, has direct applications to oil and gas extraction
The intentional usage of the annulus geometry is prevalent in several industries beyond petroleum
The literature covers topics such as slug frequency (Perez et al, 2007; Hout et al, 2003; Schulkes, 2011), holdup profile (Beggs and Brill, 1973; Bonnecaze et al, 1971), pressure drop (Strazza et al, 2011; Salem, 2008; Ilic, 1986; Ghajar and Bhagwat, 2014), mechanical losses (Liu et al, 2015) and flow regime (ArchibongEso et al, 2016; Oddie et al, 2003). We frequently find these topics in the body of work related to two-phase flow, the subjects are rare when studying the annulus
Summary
The modern-day study of two-phase and multiphase flow was spurred on by the discovery of oil and gas and the worldwide dependence on fossil fuels to power our cars and planes but countless other applications of everyday life. The topic of this paper, which is two-phase flow within an annulus, has direct applications to oil and gas extraction. Sato et al (2013) studied loss of coolant during an accident, which is highly applicable to the oil and gas industry, because of the similarities to a leak or rupture along a petroleum pipeline. The conducted studies go past environmental aspects, and there are several papers on the utilization of annular fuel rods concerning internal and external cooling, for example, Deokule et al (2015) and Blinkov et al (2010). There are more fundamental flow studies, such as the velocity distribution within the annular mixing chamber (Sun et al, 2017)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
