Injection of a Drag-Reducing Fluid into Turbulent Pipe Flow of a Newtonian Fluid

Wells, C. S.

doi:10.1063/1.1762383

Cited by 67 publications

(24 citation statements)

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“…The underlying mechanism that causes this drag reduction ͑DR͒ has been intensively studied over the last 50 years, and the original assumptions made by Lumley 1 and Metzner 2 have been verified by the numerical models, especially the direct numerical simulation ͑DNS͒. [3][4][5][6][7][8][9][10] Beginning with the study of Wells and Spangler, 11 it has been found that the polymer must be effective in the nearwall region for DR to occur. Petrie et al 12 confirmed Wells and Spangler's conclusion by carrying out experiments in a flat-plate boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Modeling of viscoelastic turbulent flow in channel and pipe

Yang

Dou

2008

Physics of Fluids

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This paper investigates turbulent flows with or without polymer additives in open channels and pipes. Equations of mean velocity, root mean square of velocity fluctuations, and energy spectrum are derived, in which the shear stress deficit model is used and the non-Newtonian properties are represented by the viscoelasticity ␣ * . The obtained results show that, with ␣ * increment, ͑1͒ the streamwise velocity fluctuations is increased, ͑2͒ the wall-normal velocity fluctuation is attenuated, ͑3͒ the Reynolds stress is reduced, and ͑4͒ there is a redistribution of energy from high frequencies to the low frequencies for the streamwise component, but dimensionless distribution over all frequencies almost remains the same as that in Newtonian fluid flows. Good agreement between the derived equations and experimental data in small drag-reduction regime is achieved, which indicates that the present model is workable for Newtonian/non-Newtonian fluid turbulent flows.

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Section: Introductionmentioning

confidence: 99%

Modeling of viscoelastic turbulent flow in channel and pipe

Yang

Dou

2008

Physics of Fluids

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“…Cela a été démontré par Wells et Spangler (1967) par injection de petites quantités de solution de polymères à différents endroits de la conduite : une injection à la paroi entraîne une réduction de frottement immé-diate, alors qu'avec une injection au centre de la conduite, la réduction de frottement correspondante est retardée, le temps que la solution de polymères diffuse jusqu'à la paroi. Virk (1975) a étudié en détail ce phénomène de drag reduction et a en particulier caractérisé expérimentalement le profil de vitesse dans la région proche de la paroi.…”

Section: Observations Phénoménologiquesunclassified

Additifs réducteurs de perte de charge en écoulement

Herzhaft

2000

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Les additifs dits réducteurs de perte de charge les plus courants sont des solutions diluées de polymères, mais il existe d'autres types d'additifs, comme des particules solides (fibres) ou des tensioactifs (sous forme de micelles cylindriques). Ces additifs en concentration infinitésimale agissent en régime turbulent et peuvent diminuer les pertes de charge en écoulement jusqu'à 80 % par rapport au solvant pur. Leur mécanisme d'action n'est pas clairement établi, mais c'est en interagissant avec la structure de la turbulence que ces additifs vont réduire la dissipation d'énergie et donc les pertes de charge. Entre deux régimes limites -un régime sans drag reducers et le régime asymptotique où la réduction de frottement est maximale -existe un régime intermédiaire où la réduction de frottement va dépendre des caractéristiques de l'écoulement et du type d'additif. Ce régime est caractérisé par l'apparition d'une couche intermédiaire élastique entre la couche visqueuse pariétale et le noyau turbulent de l'écoulement. Des comportements différents peuvent être observés suivant la conformation des additifs macromolécu-laires. L'extension des molécules en pelotes, et/ou l'alignement des polymères étendus (ou des autres additifs anisotropes) dans l'écoulement sont caractéristiques de ce phénomène de réduction de frottement.Mots-clés : réduction de frottement, additifs, perte de charge. Abstract -Drag Reducer Additives -Drag Reducer Additives (DRA) are mostly dilute polymeric solutions, but other kinds of additives exist, as solid particles (fibers) or tensioactive molecules (in cylindrical micelle form). These additives, present in very low concentration, act in turbulent flow

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“…Turbulenzintensitgtsmessungen in Rohren mit quadratischem Querschnitt [14][15][16] zeigen im Vergleich zu solchen am reinen L6sungsmittel ein Anwachsen der mit der Schubspannungsgeschwindigkeit u~= ~ normierten Turbulenzintensit,it in StrSmungsrichtung in der N~ihe der Wand. Dies wird bei Kreisrohren indessen nicht gefunden [17][18][19] [23,24]. Dabei zeigte sich, dab eine Widerstandsverminderung erst dann erhalten wird, wenn die Polymere bis in die N~ihe der Wand diffundiert sind.…”

Section: Widerstandsverminderung Bei Polymerl~sungenunclassified

Heterogene Widerstandsverminderung bei turbulenten Rohrstr�mungen

Bewersdorff

1984

Rheol Acta

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Experiments in which a viscoelastic fluid is injected along the axis of a fully developed pipe flow of a Newtonian fluid are described. For relatively high polymer concentrations the injected polymer solution forms a thread, which remains intact down the entire length of the pipe. Under these conditions remarkable drag reduction is also observed, although the polymer has not diffused noticeably into the layers near the wall.The dependence of the local drag reduction along the pipe on the total polymer concentration in the pipe, the concentration of the injected polymer solution and the Reynolds number was investigated. Furthermore, velocity profiles, turbulence intensities and Reynolds shear stresses were measured and compared with those for the solvent and a premixed homogeneous polymer solution with the same effective concentration.The shape of the velocity profiles and the Reynolds shear stresses demonstrate that the structure of turbulence in the transition or buffer layer between the viscous sublayer and the turbulent core is markedly different in the injection experiments from that in a premixed homogeneous polymer solution. The size of this region is significantly larger than in a Newtonian fluid or a homogeneous polymer solution *) Von der Abteilung Chemietechnik der Universit~it Dortmund genehmigten Dissertation; auszugsweise vorgetragen auf der Jahrestagung der Deutschen Rheologischen Gesellschaft in Berlin vom 11.-13. Mai 1981 und der Ersten Europ~tischen Rheologen-Konferenz in Graz vom 14.-16. April 1982. 979 Bewersdorff, Heterogene Widerstandsverminderung bei turbulenten RohrstrSmungen 523 and the Reynolds shear stresses are drastically reduced. From details of the structure of the turbulence and the rheological properties of the injected polymer solution it may be concluded that the large-scale structures in the pipe are influenced by the polymer thread. It seems that their motion is restricted leading to a reduced transport of energy to the dissipating small eddies and thus to the occurrence of drag reduction.

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Injection of a Drag-Reducing Fluid into Turbulent Pipe Flow of a Newtonian Fluid

Cited by 67 publications

References 5 publications

Modeling of viscoelastic turbulent flow in channel and pipe

Modeling of viscoelastic turbulent flow in channel and pipe

Additifs réducteurs de perte de charge en écoulement

Heterogene Widerstandsverminderung bei turbulenten Rohrstr�mungen

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