Drag reduction and mechanical degradation in polymer solutions in flow

Brostow, Witold

doi:10.1016/0032-3861(83)90119-2

Cited by 81 publications

(51 citation statements)

References 32 publications

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“…Brostow [34] reported that the energy supplied to a polymeric molecule in a turbulent flow leads to two processes, i.e., mechanical degradation and polymer relaxation. They proposed a model of the polymeric chain conformations based on statistical mechanics, and the effects on the DR efficiency and mechanical degradation of the polymer chains in a turbulent flow were established by considering the relationship between the extent of mechanical degradation of the polymer chains and the flow time.…”

Section: Mechanism Of Turbulent Drag Reduction With Polymersmentioning

confidence: 99%

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

2017

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Water-soluble polymers with high molecular weights are known to decrease the frictional drag in turbulent flow very effectively at concentrations of tens or hundreds of ppm. This drag reduction efficiency of water-soluble polymers is well known to be closely associated with the flow conditions and rheological, physical, and/or chemical characteristics of the polymers added. Among the many promising polymers introduced in the past several decades, this review focuses on recent progress in the drag reduction capability of various water-soluble macromolecules in turbulent flow including both synthetic and natural polymers such as poly(ethylene oxide), poly(acrylic acid), polyacrylamide, poly(N-vinyl formamide), gums, and DNA. The polymeric species, experimental parameters, and numerical analysis of these water-soluble polymers in turbulent drag reduction are highlighted, along with several existing and potential applications. The proposed drag reduction mechanisms are also discussed based on recent experimental and numerical researches. This article will be helpful to the readers to understand better the complex behaviors of a turbulent flow with various water-soluble polymeric additives regarding experimental conditions, drag reduction mechanisms, and related applications.

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Section: Mechanism Of Turbulent Drag Reduction With Polymersmentioning

confidence: 99%

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

2017

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“…Given the utility of DR, there is a number of explanations why it takes place, none of them generally accepted. One of us developed a model of the DR mechanism already in 1983 5) , but it remained a conjecture for lack of proof. Below we report direct experimental evidence now obtained which shows the validity of the model, plus point out results of computer simulations and other evidence supporting the model.…”

mentioning

confidence: 97%

“…The low-ppm DR results also support the model proposed in ref. 5) : the very presence of macromolecular chains causes solvation and creates domains powerful enough to produce such significant effects.…”

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confidence: 99%

Drag reduction and solvation in polymer solutions

Brostow¹,

Majumdar

Singh

1999

Macromol. Rapid Commun.

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SUMMARY: A model is described which explains drag reduction (DR) in dilute polymer solutions in terms of solvation of macromolecular chains and formation of relatively stable domains. The domains partly suppress the vortex formation, act as energy sinks, and also play a role in mechanical degradation in flow (MDF). We report ultrasonically determined solvation numbers for a series of copolymers with the same chemical structure but differing widely in their intrinsic viscosities. The solvation numbers confirm the model. Thus, we have a criterion for selection of DR agents with low MDF for: oil well operations; crude oil transport; fire fighting; high sewer throughput; irrigation; hydrotransport of solids; marine applications; and biomedical applications including the arteriosclerosis prevention.

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“…Additionally we know that a flocculating agent is expected to be also a drag reduction (DR) agent. A model of DR developed earlier assumes that each polymer chain pervades a volume in the liquid medium exceeding the dimensions of that chain [20,10]. This explains DR efficacy at low concentrations such as 10 ppm.…”

Section: Flocculants Inmentioning

confidence: 99%

Settling rates for flocculation of iron and manganese ore‐containing suspensions by cationic glycogen

Brostow

Lobland

Pal

et al. 2008

Polymer Engineering & Sci

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Novel flocculants have been synthesized on the basis of glycogen. The efficiency of cationic glycogen can be explained in terms of Singh's qualitative easy approachability model (EAM). The jar test was used previously to evaluate flocculation efficacy, but we have recently shown that a plot of interface height vs. settling times provides a better measure. In accord with the EAM, a one-to-one correspondence between settling velocity and radius of gyration of flocculants in various solutions has been demonstrated, providing quantitative proof of the EAM. Now the flocculation efficacy of cationic glycogen is evaluated by determination of settling times in both iron and manganese ore suspensions and compared with the performance of other polymer flocculants. Its superior flocculation efficacy over commercial flocculants and other flocculants synthesized by us is demonstrated.

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Drag reduction and mechanical degradation in polymer solutions in flow

Cited by 81 publications

References 32 publications

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

Drag reduction and solvation in polymer solutions

Settling rates for flocculation of iron and manganese ore‐containing suspensions by cationic glycogen

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