Effect of Pipe Diameter on the Performance of Drag-Reducing Polymers in Annular Gas-Liquid Flows

In a recent paper, Al-Sarkhi and Hanratty examined the influence of a drag-reducing polymer on air-water annular flows in a 9.53 cm pipeline. This paper describes similar studies in a 2.54 cm pipe, for which the annular flow has different characteristics and for which the friction factors assume larger values in air-water systems. Both studies show a maximum drag reduction that is accompanied (in most cases) by a change to a stratified flow for which the concentration of drops in the gas phase is zero or close to zero, and for which the friction factor is about 1.5 times what would be observed for air flowing alone. The amount of drag reduction, therefore, depends on the magnitude of the friction factor for the air-water flow. Drag reductions up to 63% were observed in the 2.54 cm pipe. This is to be compared with the 48% previously achieved in the 9.54 cm pipe. Larger concentrations of polymer are needed to obtain maximum drag reduction in the smaller pipe.

[1]  Thomas J. Hanratty,et al.  Entrainment for horizontal annular gas-liquid flow , 1984 .

[2]  Thomas J. Hanratty,et al.  Generation of waves in the concurrent flow of air and a liquid , 1965 .

[3]  Investigation of Separated Flow Model in Annular Gas-Liquid Two-Phase Flows , 1979 .

[4]  T. J. Hanratty,et al.  Effect of drag-reducing polymers on annular gas–liquid flow in a horizontal pipe , 2001 .

[5]  Thomas J. Hanratty,et al.  Influence of drag-reducing polymers on turbulence: effects of Reynolds number, concentration and mixing , 1999 .

[6]  W. G. Tiederman,et al.  Drag reduction and turbulent structure in two-dimensional channel flows , 1991, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[7]  Thirumalai,et al.  Drag reduction in turbulent flows by polymers. , 1991, Physical review letters.

[8]  G. Hewitt,et al.  DRAG REDUCTION WITH ADDITIVES IN MULTIPHASE FLOW: A LITERATURE SURVEY , 1999 .

[9]  Christopher White,et al.  The onset of drag reduction by dilute polymer additives, and the maximum drag reduction asymptote , 2000, Journal of Fluid Mechanics.

[10]  T. J. Hanratty,et al.  Droplet flux distributions and entrainment in horizontal gas-liquid flows , 1996 .

[11]  B. A. Toms,et al.  Some Observations on the Flow of Linear Polymer Solutions Through Straight Tubes at Large Reynolds Numbers , 1948 .

[12]  J. P. Brill,et al.  Drag reduction in two‐phase annular‐mist flow of air and water , 1976 .

[13]  Thomas J. Hanratty,et al.  Interfacial drag and film height for vertical annular flow , 1985 .

[14]  W. Willmarth,et al.  Modifying turbulent structure with drag-reducing polymer additives in turbulent channel flows , 1992, Journal of Fluid Mechanics.