Adsorption measurements in dilute solutions of a drag-reducing polymer

Arunachalam, Vr.; Fulford, George D.

doi:10.1016/0009-2509(71)80020-9

Cited by 15 publications

(3 citation statements)

References 19 publications

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“…Some workers (12,15,57) have postulated that an adsorbed layer of polymer molecules at the interface of flowing liquid and wall continues to function in a drag-reduction sense when the bulk of the polymer solution has been displaced by the base solvent. The suggestion that adsorbed polymer layers play an important role in the drag reduction mechanism is at first glance a thoroughly intriguing one and interest in it still persists (3,10).…”

Section: Possible Factors Involved In Drag Reductionmentioning

confidence: 99%

The Drag Reduction Phenomenon. Observed Characteristics, Improved Agents, and Proposed Mechanisms

Little¹,

Hansen²,

Hunston³

et al. 1975

Ind. Eng. Chem. Fund.

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An overview is presented of experimental and theoretical work conducted at the Naval Research Laboratory on the reduction of hydrodynamic drag. The work establishes the effectiveness of certain chemical additives in reducing drag and defines the character of laminar, transitional, and turbulent flows when such additives are present. A variety of new additives for reducing drag have been developed during the program, and their unique properties are also summarized. Finally, the theoretical work is used as a basis for assessing the relative merits of proposed explanations for the drag reduction phenomenon.

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Section: Possible Factors Involved In Drag Reductionmentioning

confidence: 99%

The Drag Reduction Phenomenon. Observed Characteristics, Improved Agents, and Proposed Mechanisms

Little¹,

Hansen²,

Hunston³

et al. 1975

Ind. Eng. Chem. Fund.

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“…Specific wall interactions, and their relevance to drag reduction phenomena, are put forth by El'perin et al (1963) who suggested the Occurrence of adsorption of the polymer at the pipe wall. Arunachalam and Fulford (1971) have done experiments to measure the kinetics of adsorption and have found higher polymer concentrations near the wall in a pipe flow. Hand and Williams (1973) have proposed that an absorbed and entangled polymer layer must be involved in order to provide the dimensions necessary to reach into the outer wall region where most turbulence is produced and dissipated.…”

Section: ''Fine Structure" Disappears In a Drag-reducing Fluid;mentioning

confidence: 99%

Turbulent dispersion in drag‐reducing fluids

Taylor

Middleman

1974

AIChE Journal

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Turbulent pipe flow was examined by measuring the radial dispersion of dyed fluid introduced at an axial point source within the flow. From the classical theoretical results of G. I. Taylor it was possible thereby to calculate various parameters that characterize the structure of the turbulent flow field. A comparison was made between water, and aqueous solutions of polyethylene oxide (Polyox) at concentrations up to 50 ppm (by weight). Results indicate that Polyox affects the turbulence in the following ways:(1) intensity is reduced, (2) the energy spectrum is shifted toward low frequency, (3) dispersion occurs largely through large scale motion, and intermittency is increased. Indication is also seen that a simple exponential form for the Lagrangian correlation coefficient is superior to other often recommended models. A. RICHARD SCOPEWhile drag reduction phenomena in pipe flows are well documented, the mechanism whereby dilute polymeric additives affect turbulence is not completely understood. In Particular, Some Previous suggests that One must solvent in the neighborhood of the pipe wall to explain observations. The goal of this work was to examine removed from wall influences.suring the radial dispersion of dyed fluid introduced at an axial point source within the pipe. From the classical work of G. 1. ~~~l~~ on dispersion by continuous movements it was possible to calculate the various parameters A comparison was made between water, and aqueous tions up to 50 ppm (by weight). Polyox is a well-known drag reducing additive.invoke 'Pecific interactions between the Polymer and that characterize the structure of a turbulent flow field.turbulent phenomena in the of a pipe flow, solutions of polyethylene oxide (Polyox) at concentra-A classical dye-tracer study was carried out by mea- CONCLUSIONS AND SIGNIFICANCEThrough the experiments described it was possible to obtain reliable measurements of turbulent parameters. The results indicate the following conclusions can be drawn: models.and intermittency is increased. 4. A simple exponential form for the Lagrangian correlation coefficient Seems to be superior to other suggested 1. Turbulence in a drag-reducing fluid has a smaller intensity than in the solvent alone, under otherwise identical conditions.2. The energy spectrum is shifted, by the polymer additive, toward low frequency, large-scale, fluctuations. dispersion occurs principally through large-scale motion, Of particular significance is the demonstration that the of drag-reducing fluids is not localized at the pipe wall but extends into the turbulent core. Thus, proposed mechanisms of drag reduction which rely entirely on alleged wall adsorption or orientation of the polymer molecules are incomplete.3. ''Fine structure" disappears in a drag-reducing fluid;It is well established that certain types of transport processes in fluids can be drastically altered by the addition of extremely small quantities of soluble polymeric substances to the fluids. The most common example of this phenomenon arises in the turbu...

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“…(1) In a dashpot apparatus where the fluid was forced to escape through the annular gap between piston and cylinder wall under laminar flow conditions (2) Under turbulent pipe flow in a 1 mm bore tube, Reynolds number 15,000, in which the wall shear stress was of the same order as that calculated for (1) above.…”

Section: Summary Of Drag-reduction Research In Laboratoriesmentioning

confidence: 99%

Progress in Frictional Drag Reduction Summer 1971 to Summer 1972

Granville¹

1973

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Adsorption measurements in dilute solutions of a drag-reducing polymer

Cited by 15 publications

References 19 publications

The Drag Reduction Phenomenon. Observed Characteristics, Improved Agents, and Proposed Mechanisms

The Drag Reduction Phenomenon. Observed Characteristics, Improved Agents, and Proposed Mechanisms

Turbulent dispersion in drag‐reducing fluids

Progress in Frictional Drag Reduction Summer 1971 to Summer 1972

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