DRAG REDUCTION - Polymer Solutions, Soap Solutions, and Solid Particle Suspensions in Pipe Flow

Patterson, G. K.; Zakin, J. L.; Rodriguez, J. M.

doi:10.1021/ie50709a005

Cited by 119 publications

(24 citation statements)

References 26 publications

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“…Many high polymer and several soap solutions in both water and hydrocarbon solvents have been shown to be drag reducing (Patterson et al, 1969). In these systems it is generally agreed that drag reducing behavior is associated with the viscoelastic nature of the solutions which is caused by the high molecular weight polymer molecules or by the soap micelles in solution.…”

Section: Conclusion and Significancementioning

confidence: 99%

Polyethylene vs. stainless steel impellers for crystallization processes

1973

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The importance of controlling the crystal size distribution of the product from an industrial crystallizer has long been recognized. To do this, some control over the nucleation and growth rates of crystals must be maintained. The crystal growth rate can be influenced by varying degrees of agitation, supersaturation, and temperature. However, these variables also have a major effect on the nucleation rate, so that it is seldom possible to change one of these quantities without simultaneously changing the other. It is the purpose of this note to discuss one means of substantially influencing the nucleation rate without affecting the growth rate.The role of crystal impacts in determining the nucleation rates was established by Clontz and McCabe (1971) and Johnson et al. (1972). Ottens and deJong (1972) have presented data to indicate that the major source of nucleation in an industrial crystallizer is at the impel'er , if there is internal mixing, or at the pump, if the mixing in the crystallizer is accomplished by external recycle Johnson et a]. (1972) also show that when a single crystal is impacted by a polyethylene rod, whose face is parallel to the crystal face being impacted, no new crystals are Kenerated. This can be contrasted to the generous number of crystals produced by impact with a metal rod. Their system was magnesium sulfate heptahydrate.On the basis of these reports an experimental plan to investigate the influence of the material of construction of the impeller in a stirred tank crystallizer was formulated. The crystallizer was a cylindrical Pyrex battery jar 15.25 cm in diameter and filled to a depth ol' 17.15 cm Three equally spaced plexiglass baffles extending to within 3 cm of the bottom were attached to the crystallizer. A fitted plexiglass cover was constructed to accommodate the impeller shaft, a thermometer which could be read to O.l"C, and seed crystal insertion. The entire apparatus was placed in a constant temperature bath. The impellers used were 5.1 cm in diameter, three bladed, with a square pitch, and located 9 cm from the bottom of the crystallizer.In all of the experiments of this series, the impeller speed was held at 700 rev./min., a value which kept the seed crystal adequately suspended. The size of the seed crystals was held essentially constant at about 5 mm x 2 mm x 2 mm; when deviations from this size occurred the results were erratic. Supersaturation was kept at 2°C and the temperature at about 33 to 35°C. A typical run went as follows: A solution of MgS04.7H20 was prepared, filtered, and placed in the crystallizer. The saturation temperature of the solution was determined by refractive index and the temperature of the solution was adjusted to 2°C above saturation. A seed crystal of the appropriate size and shape, and which had been recrystallized below 48.2"C to ensure the pure heptahydrate form, was inserted into the crystallizer and cured for 16 minutes with agitation. Shorter curing times gave excessively high crystal counts. Agitation was discontinued and the solut...

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Section: Conclusion and Significancementioning

confidence: 99%

Polyethylene vs. stainless steel impellers for crystallization processes

1973

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“…of Hydrodynamics, Czech Academy of Sciences, Prague, Czech Republic Reduction of friction losses in turbulent flows caused by the presence of low concentrations of aluminum disoap and high polymer additives was first reported about fifty years ago (Mysels, 1949;Toms, 1948). Since then there have been a large number of studies of drag reduction, most of which used high polymers, and several excellent reviews exist (Patterson et a]., 1969;Hoyt, 1972;Virk, 1975;Sellin, et al 1982a,b;Hoyt, 1986;Shenoy, 1984). High polymer additives have found important niche applications in crude oil and petroleum product transport (Burger et al, 1982;Motier et al, 19841, in fire fighting (Union Carbide, 19661, in increasing sewer flows (Sellin, 1977) and in jet cutting (Summers andZakin, 197.51, Virk et al (1970, 1971) proposed equations for a limiting maximum drag reduction asymptote for high polymers and also for an elastic sublayer velocity profile limit.…”

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confidence: 99%

New limiting drag reduction and velocity profile asymptotes for nonpolymeric additives systems

1996

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“…Polymer backbone structure and side groups as well as solvent-polymer interactions determine the flexibility of the molecule [Patterson et al, 1969] as well as the polymer electrostatic charge in aqueous systems. Polymer backbone structure and side groups as well as solvent-polymer interactions determine the flexibility of the molecule [Patterson et al, 1969] as well as the polymer electrostatic charge in aqueous systems.…”

Section: Effect Of Polymer Molecular Structurementioning

confidence: 99%