Drag reduction in turbulent flow due to additives: a report on Euromech 52

Bark, Fritz H.; Hinch, E. J.; Landahl, M. T.

doi:10.1017/s0022112075000729

Cited by 18 publications

(7 citation statements)

References 26 publications

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“…A reduction in turbulent flow is also observed when the polymer polyisobutylene (PIB) is dispersed in benzene or cyclohexane, and when PEO or PAM are dispersed in turbulent water [63]. When the concentration of polymer additives is gradually increased, drag reduction (DR) increases upto a saturation value, before eventually decreasing [64]. This phenomenon is widely utilized in irrigation networks, sewerage systems, oil pipelines and for extending the range of fire-fighting equipment.…”

Section: Turbulent Drag Reductionmentioning

confidence: 99%

Novel experimentally observed phenomena in soft matter

Bandyopadhyay

2013

Pramana - J Phys

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Abstract. Soft materials such as colloidal suspensions, polymer solutions and liquid crystals are constituted by mesoscopic entities held together by weak forces. Their mechanical moduli are several orders of magnitude lower than those of atomic solids. The application of small to moderate stresses to these materials results in the disruption of their microstructures. The resulting flow is non-Newtonian and is characterised by features such as shear rate-dependent viscosities and nonzero normal stresses. This article begins with an introduction to some unusual flow properties displayed by soft matter. Experiments that report a spectrum of novel phenomena exhibited by these materials, such as turbulent drag reduction, elastic turbulence, the formation of shear bands and the existence of rheological chaos, flow-induced birefringence and the unusual rheology of soft glassy materials, are reviewed. The focus then shifts to observations of the liquid-like response of granular media that have been subjected to external forces. The article concludes with examples of the patterns that emerge when certain soft materials are vibrated, or when they are displaced with Newtonian fluids of lower viscosities.

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Section: Turbulent Drag Reductionmentioning

confidence: 99%

Novel experimentally observed phenomena in soft matter

Bandyopadhyay

2013

Pramana - J Phys

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“…This hose has a valve (2) that serves to control the pressure inside the device's chamber (5). The pressure is also monitored by a pressure gauge (3) placed at the outlet of the valve (2). Once the working pressure is established inside the chamber (5), another valve (7) is opened permitting the fluid to flow through the capillary (9) and escape the system through the expander (10).…”

Section: Pressure Drop Testmentioning

confidence: 99%

“…The drag reduction can be manifested as a lower coefficient of friction, a decrease in pressure drop per unit of pipe length or a reduction in the energy required to pump a fluid or propel an object through a fluid. [1][2][3][4] The British chemist B. A. Toms [1] (1949) was the first to publish data on drag reduction (the phenomenon is also known as the Toms Effect), reporting lower friction factors than expected for diluted solutions of poly(methyl metacrylate) in monochlorobenzene under turbulent flow through pipelines.…”

Section: Introductionmentioning

confidence: 99%

“…The large number of recent publications in this area attests to the fact that drag reduction continues to be an important research topic. [14][15][16][17][18][19][20][21][22][23][24] There are reports in the literature of various solvent/additive systems that have drag reduction properties, including diluted solutions of natural or synthetic polymers with high molar mass, [1][2][3][4][5][6][7][8][9][10][11][12] surfactants and micellar systems, [21,25] suspensions of insoluble particles such as fine grains or fibers [26,27] and polymer solutions mixed with soaps or fibers. [28][29][30][31][32] In general, any soluble polymer that has a sufficiently high molar mass (greater than 1 Â 10 5 ), or that is able to form large aggregates, can be effective in reducing friction in a turbulent regime.…”

Section: Introductionmentioning

confidence: 99%

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Development of a Method to Evaluate the Performance of Aqueous Polymer Solutions as Drag Reduction Agents in Bench Scale

Figueiredo

Almeida

Costa

et al. 2006

Macromolecular Symposia

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Summary: This work describes a method to evaluate, in reduced scale, the performance of polymer samples as drag reduction agents in aqueous solutions. To measure the pressure drop in a turbulent regime, a specially adapted capillary viscosimeter was used, with reduced dimensions adapted to produce the desired regime and adequate pressure measurement points. To verify the technique's reliability, samples of polyacrylamide were synthesized with different molar masses, by varying the quantity of the polymerization initiator. The molar masses obtained were determined by size exclusion chromatography (SEC). The efficiency of the polymer as a drag reducer, as expected, increased as the molar mass increased, which validates the use of this method to study the drag reduction properties of polymer materials in aqueous solutions.

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“…The phenomenon of the use of additives for drag reduction in turbulent flow has been the subject of intensive research since decades ago. The study attracted the attention of researchers because of the use of additives in small quantities as only part per million can reduce drag by almost 50% (Bark et al, 1975). Although this effect has been known for almost half a century, the physical mechanism that causes this drag reduction has still not been clearly identified.…”

Section: Introductionmentioning

confidence: 99%

Improving the flow in pipelines by Cocos nucifera fiber waste

Marmy¹

2012

Int. J. Phys. Sci.

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In this study, fiber performance as drag reducing agent in aqueous media flow in pipeline was investigated. Use of fiber from the Cocos nucifera (coconut) to reduce friction in pipe flow is a new invention in the fluid transport technology. The use of coconut fiber in liquid pipelines can reduce operating costs which can have a significant impact on the revenue and profit of the pipeline company. An experiment facility with three different pipe diameters (0.0127, 0.0254 and 0.0381 m, respectively) was built in order to investigate the performance of these fiber suspensions as drag reducing agent (DRA). The dependence of drag reduction on various factors including fiber concentration, pipe length, pipe diameter and solution flow rate is investigated. Rheological test were investigated and conducted using programmable rheometer. It was observed that a small amount of fiber in suspension causes drag reduction in pipeline. The percent drag reduction (%DR) is calculated using the obtained experimental data in presence of the DRA. The results showed that percentage drag reduction increases by increasing the coconut fiber concentration and increasing flow rate. Adding the coconut fiber to the water, percentage drag reduction in pipeline can reach up to 56%.

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Drag reduction in turbulent flow due to additives: a report on Euromech 52

Cited by 18 publications

References 26 publications

Novel experimentally observed phenomena in soft matter

Novel experimentally observed phenomena in soft matter

Development of a Method to Evaluate the Performance of Aqueous Polymer Solutions as Drag Reduction Agents in Bench Scale

Improving the flow in pipelines by Cocos nucifera fiber waste

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