Interfacial friction in upward annular gas–liquid two-phase flow in pipes

Abstract

Accurate prediction of interfacial friction between the gas and liquid in annular two-phase flow in pipes is essential for the proper modelling of pressure drop and heat transfer coefficient in pipeline systems. Many empirical relationships have been obtained over the last half century. However, they are restricted to limited superficial liquid and gas velocity ranges, essentially apply to atmospheric pressures, and the relationships are only relevant for pipes with inner diameters between 10 and 50 mm. In this study, we carried out experiments in a large diameter flow loop of 101.6 mm internal diameter with the superficial gas and liquid ranges of 11-29 m/s and 0.1-1.0 m/s respectively. An examination of published interfacial friction factor correlations was carried out using a diverse database which was collected from the open literature for vertical annular flow. The database includes measurements in pipes of 16-127 mm inner diameter for the liquid film thickness, interfacial shear stress, and pressure gradient for air-water, air-water/glycerol, and argon-water flows. Eleven studies are represented with experimental pressures of up to 6 bar. Significant discrepancies were found between many of the published correlations and the large pipe data, primarily in the thick film region at low interfacial shear stress. A correlation for the interfacial friction factor was hence derived using the extensive database. The correlation includes dimensionless numbers for the effect of the diameter across pipe scales to be better represented and better fit the wide range of experimental conditions, fluid properties, and operating pressures.

Sand minimum transport conditions in gas–solid–liquid three-phase stratified flow in a horizontal pipe at low particle concentrations

“…The sand mixture friction factors were consistently above those for smooth pipes which is consistent with observations by other authors (e.g. (Aliyu et al, 2017cBelt et al, 2009)) who reported in increase in friction factor with increased interfacial friction. This is also related to increased pressure drop within the pipe, as given by the relationship in Equation 4.…”

“…It consists of a horizontal pipe with an inner diameter of 0.0504 m. The 2-inch test rig constitutes a loop length of 25 m; 10.5 m of that is PVC pipe that serves as the water supply inlet and the remainder is of a Perspex pipe material. Two flush-mounted conductivitybased sand monitoring sensors (uncertainty of ±3.3% and identical to those employed by(Aliyu et al, 2017bAliyu et al, 2017;Almabrok et al, 2016) in measuring liquid film thickness), given inFigure 1 (b)and (c) were installed about 6 m after the air and sand injection point along the horizontal pipe but 0.21 m apart from each other. The second sand sensor was placed within the conductivity ring sensors (Fajemidupe, 2016).…”

Multi-layer flows of immiscible fractional second grade fluids in a rectangular channel

“…It has been seen that the fluid velocity decreases with the increase in the values of the fluids fractional parameters. Other interesting results relating to sigle layer fluid flow [18][19][20][21] and simultaneous flow two or more fluids can be seen in [7,15,[22][23][24][25][26]. To the best of authors knowledge, the study of simultaneous flow of multi-layer immiscible second grade not exist in literature.…”

Investigating the impact of dissolved natural gas on the flow characteristics of multicomponent fluid in pipelines

“…However, it is quite complex process and difficult to develop a reliable model for predicting the occurrences correctly [19,30]. That is reason, experimental determinations and empirical correlations are applied to improve the reliability of the thermodynamic and hydrodynamic aspects of the mathematical models [3,9,23].…”