Local drag reduction due to injection of polymer solutions into turbulent flow in a pipe. Part I: Dependence on local polymer concentration

McComb, W. D.; Rabie, Lotfy

doi:10.1002/aic.690280405

Cited by 70 publications

(28 citation statements)

References 20 publications

(17 reference statements)

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“…Investigations of Wells and Spangler [29] and McComb and Rabie [22,30] confirmed the hypothesis that the drag reducing macromolecules affect the near-wall region of the pipe flow. The centre-line injection of dilute polymer solutions leads to a drag reducing effect only when the macromolecules have been transported into the near-wall region by turbulent diffusion.…”

Section: Polymer Drag Reduction In Turbulent Pipe Flowsmentioning

confidence: 65%

“…A widely accepted hypothesis of the mechanism responsible for homogeneous drag reduction is that the microscale eddies in the buffer zone of the turbulent boundary layer are suppressed [21,22]. It is known from flow visualization experiments [23] that the macromolecules affect the sublayer instability which produces jet-like vortices, the so-called bursts, which erupt into the boundary layer and lead to the production of turbulent energy (see also [24]).…”

Section: Polymer Drag Reduction In Turbulent Pipe Flowsmentioning

confidence: 97%

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Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Frings

1988

Rheol Acta

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Abstract:The results of an experimental study of the injection of concentrated polymer solutions into the near-wall region of a turbulent pipe flow are reported. The injection experiments described here show drag reduction that was significantly larger than that obtained for homogeneous polymer solutions of the same average concentration. Local drag reduction and friction behavior was obtained by measuring pressure differences over a test section of 13 m in length. Furthermore the flow behaviour of the injected polymer solution was in.vestigated by flow visualization experiments. Velocity profile measurements elucidate in case of near-wall injection that the turbulent structure could be altered in the ~aear-wall and also in the core region of the pipe flow, indicating that the polymer lumps and threads created by the near-wall injection are able to influence a much wider spectrum of turbulent eddies in comparison to centreline injection or, all the more, to homogeneous drag reduction.

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Section: Polymer Drag Reduction In Turbulent Pipe Flowsmentioning

confidence: 65%

Section: Polymer Drag Reduction In Turbulent Pipe Flowsmentioning

confidence: 97%

Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Frings

1988

Rheol Acta

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“…One of the most extensive sets of polymer experimental data, that of McComb and Rabie [13], also offer some confirmation of the thread idea. McComb and Rabie injected solutions of 3000 wppm poly(ethylene oxide) together with a salt tracer, on the centreline of a pipe to give an average 10.8 wppm polymer concentration in the pipe.…”

Section: Introductionmentioning

confidence: 72%

Drag reduction by centrally-injected polymer ?threads?

Hoyt

Sellin

1988

Rheol Acta

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In the extensive literature on polymer drag reduction, it has occasionally been reported that a continuous thread of a high-concentration polymer solution injected into the axis of a pipe produces a drag-reduction effect on the water-flow in the pipe. The "thread" seems to persist through the length of the pipe and little if any diffusion of polymer to the walls of the pipe is apparent.All previous experiments have been at a relatively low Reynolds number, and the purpose of the present work was to evaluate the technique at pipe Reynolds numbers above 10 s. Experiments were carried out in a 53 mm diameter stainless steel pipe 20 m in length, constructed to high tolerances. The polymer, Separan AP-203, was injected as a 0.5% solution from an axially placed nozzle at the bellmouth entrance.The experiments show that the central thread provided drag-reduction almost equivalent to pre-mixed solutions of the same total polymer concentration flowing in the pipe. Overall concentrations of 1, 2, 4, and 20 parts-per-million were used. Moreover, the effects were additive: 2 ppm thread overall concentration plus 2 ppm pre-mixed gave drag reductions equivalent to 4 ppm of either type. Reynolds numbers of up to 300 000 were investigated.Attempts to visualize the polymer thread were inconclusive. The dyed polymer thread was viewed through a window at the downstream end of the pipe. The predominate appearance was that of a dispersion of globules of high-concentration polymer.

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“…Selon une hypothèse différente, de petites quantités de polymères diffuseraient du filament central vers la région de l'écoulement proche de la paroi, ce qui suffirait à provoquer la réduction de frottement ; le mécanisme serait alors similaire au mécanisme de drag reduction classique. McComb et Rabie (1982) proposent cette hypothèse à partir de mesures de profils de concentration, et plus récemment, Smith et Tiederman (1991) l'ont confirmée à partir d'expériences de diffusion de traceur. Hoyt et Sellin (1991) attribuent le phénomène de drag reduction à la diffusion de molécules de polymères depuis le filament central vers la région de l'écoulement proche de la paroi pour des nombres de Reynolds élevés, alors qu'à de faibles nombres de Reynolds, cet effet serait dû à l'interaction du filament central avec la turbulence à grande échelle du coeur de l'écoulement.…”

Section: Drag Reduction Hétérogèneunclassified

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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Local drag reduction due to injection of polymer solutions into turbulent flow in a pipe. Part I: Dependence on local polymer concentration

Cited by 70 publications

References 20 publications

Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Heterogeneous drag reduction in turbulent pipe flows using various injection techniques

Drag reduction by centrally-injected polymer ?threads?

Additifs réducteurs de perte de charge en écoulement

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