Drag reduction by polymer–polymer mixtures

Malhotra, J. P.; Chaturvedi, P. N.; Singh, R. P.

doi:10.1002/app.1988.070360409

Cited by 18 publications

(7 citation statements)

References 10 publications

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“…The product, BC, is a polymer, and a synergistic effect of drag reduction by BC is expected (22,23). However the main production stage of BC was after the logarithmic growth phase and the effect mentioned above is not primarily important for BC production.…”

Section: Discussionmentioning

confidence: 99%

Effect of Addition of Water-Soluble Polysaccharides on Bacterial Cellulose Production in a 50-L Airlift Reactor

et al. 2001

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Bacterial cellulose (BC) production was carried out in a batch cultivation of Acetobacter xylinum in a 50-L internal loop airlift reactor by addition of water-soluble polysaccharides into the medium. When 0.1% (w/w) agar was added, BC production reached 8.7 g/L compared with 6.3 g/L in the control, and duration of the cultivation period to reach the maximum concentration of BC was almost half of that without addition of polysaccharides. During cultivation, BC was formed into pellets whose size was smaller when the productivity of BC was higher, indicating that increase in the relative viscosity by addition of polysaccharides hindered formation of large clumps of BC and increase in the volumetric oxygen transfer coefficient at high flow rate led to increase in BC productivity.

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Section: Discussionmentioning

confidence: 99%

Effect of Addition of Water-Soluble Polysaccharides on Bacterial Cellulose Production in a 50-L Airlift Reactor

et al. 2001

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“…They also concluded that flow conditions can affect the degree of deviation from additivity. Malhotra et al (1988) verified DR of PAM/GG, GG/XG, and PAM/ XG binary solutions and concluded that the degree of DR and synergism depend on polymer concentration and flow rate. They also concluded that positive deviation in additivity occurs when both polymers are rigid.…”

Section: Introductionmentioning

confidence: 87%

Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

Habibpour

Clark

2017

Pet. Sci.

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Partially hydrolyzed polyacrylamide (HPAM) as the main component of slickwater fracturing fluid is a shear-sensitive polymer, which suffers from mechanical degradation at turbulent flow rates. Five different concentrations of HPAM as well as mixtures of polyacrylamide/ xanthan gum were prepared to investigate the possibility of improving shear stability of HPAM. Drag reduction (DR) measurements were performed in a closed flow loop. For HPAM solutions, the extent of DR increased from 30% to 67% with increasing HPAM concentration from 100 to 1000 wppm. All the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing period. Results indicated that the resistance to shear degradation increased with increasing polymer concentration. DR efficiency of 600 wppm xanthan gum (XG) was 38%, indicating that XG was not as good a drag reducer as HPAM. But with only 6% DR decline, XG solution exhibited a better shear stability compared to HPAM solutions. Mixed HPAM/XG solutions initially exhibited greater DR (40% and 55%) compared to XG, but due to shear degradation, DR% dropped for HPAM/XG solutions. Compared to 200 wppm HPAM solution, addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/ XG mixed polymer solutions. Keywords Slickwater Á Polyacrylamide Á Xanthan gum Á Drag reduction Á Shear stability Edited by Xiu-Qin Zhu.

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“…Solutions of polymer blends have been studied in shear and elongational flows mainly to ascertain the effect of the flow on the miscibility of the system. For miscible mixtures, drag reduction experiments in turbulent flows through pipes13, 14 have shown that the mixture has drag reducing capabilities that exceed that of solutions of each of the individual polymers, especially when at least one of the polymers has a semirigid structure. This motivated our previous studies of the flow of solutions of polymer blends through porous media,15 where we found that while PEO solutions exhibit extension thickening when they flow through porous media, hydroxypropyl guar (HPG) solutions were shear thinning at high concentrations.…”

Section: Introductionmentioning

confidence: 99%

Flow of mixtures of poly(ethylene oxide) and hydrolyzed polyacrylamide solutions through porous media

Kauser

Santos

Delgado

et al. 1999

J. Appl. Polym. Sci.

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In this work, the porous media flow of polymer solutions of poly(ethylene oxide) (PEO), hydrolyzed polyacrylamide (HPAA), and their blends is investigated. Aqueous solutions of PEO exhibit critical extension thickening when flowing through porous media. HPAA solutions also exhibit critical extension thickening in excess salt environments, but their behavior changes to a more gradual extension thickening when dissolved in deionized water. The mixtures of solutions of HPAA and PEO therefore vary its porous media flow behavior, depending on the ionic environment. In deionized water, a critical extension thickening similar to that obtained with PEO is still observed when HPAA is mixed in at concentrations low enough so that its apparent viscosity does not mask the influence of PEO. In the presence of salt, only a critical extension thickening is observed, which is attributed to transient network formation of both PEO and HPAA molecules. The mixtures generally exhibit a less critical behavior and display a lower than expected sensitivity of the onset Reynolds number for extension thickening with concentration. The results presented herein indicate that interspecies molecular interactions through transient network formation and the associated flow modification play a major role in determining the complex non-Newtonian flow behavior of these polymer solutions.

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Drag reduction by polymer–polymer mixtures

Cited by 18 publications

References 10 publications

Effect of Addition of Water-Soluble Polysaccharides on Bacterial Cellulose Production in a 50-L Airlift Reactor

Effect of Addition of Water-Soluble Polysaccharides on Bacterial Cellulose Production in a 50-L Airlift Reactor

Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

Flow of mixtures of poly(ethylene oxide) and hydrolyzed polyacrylamide solutions through porous media

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