[PDF] Effect Of Polymer Coiling On Drag Reduction eBook

Author :
Publisher :
Page : 121 pages
File Size : 38,81 MB
Release : 1966
Category :
ISBN :

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Tube flow data indicate that the drag reduction of high molecular weight polymer solutions decreases in an orderly fashion with inc.eased molecular coiling of the polymer. A correlating equation for this effect is presented. For three polymers at four concentrations the maximum drag reduction was obtained at temperatures less than 105F and at 140F solutions of all three polymers suffered a decrease in drag reduction. A graphical relationship is presented that qualitatively correlates the variation of viscosity and drag reduction caused by a variation in temperature. A decrease in drag reduction occurs if low concentration of high molecular weight polymers are subjected to steady state turbulent tube flow. A slow decrease in viscosity of high molecular weight solutions due to physical adsorption on the solid surfaces in glassware as well as chemical degradation during static storage can be mitigated by adding isopropanol or using deionized water. The average molecular weight of different samples of the same polymer can vary by as much as 50 percent. (Author).

Author : Gin Chain Liaw
Publisher :
Page : 318 pages
File Size : 26,14 MB
Release : 1968
Category : Drags (Hydrography)
ISBN :

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"The effects of polymer chain flexibility, molecular weight and entanglement capacity, and of polymer solution concentration on drag reduction in nonpolar solvents were studied in this investigation. Three samples of polydimethyl siloxane in toluene, five samples of polyethylene oxide in benzene, two samples of cis-polyisoprene in toluene, trans-polyisoprene in toluene, cis-polybutadiene in toluene, ethyl cellulose in toluene and a copolymer of epichlorohydrin and polyethylene oxide in toluene were studied. Molecular weights of all polymers were estimated from intrinsic viscosity, except for the molecular weight of the copolymer which was given by the manufacturer. Turbulent and laminar flow pressure drop data were obtained in four capillary tubes (0.107, 0.0642, 0.0328 and 0.0104 inch ID) for all the polymer-solvent systems. Turbulent flow pressure drop data for some of the above polymer-solvent systems were also obtained in the pipe flow unit (2.0, 1.0 and 0.51 inch ID). For a given tube, at lower concentrations the normal transition region appeared between laminar and turbulent regions; as the concentration increased, the transition tended to disappear. At constant solution concentration, the transition region tended to disappear as the tube diameter decreased ... Correlations were obtained for estimating the amount of drag reduction for "dilute" and "concentration" solutions. Both correlations were tested with the polymer-solvent systems studied in this investigation and with data obtained from literature ... The effect of degradation on drag reduction was more noticeable at lower concentrations than at higher concentrations. This suggests that the absolute rate of molecular degradation may have been approximately the same for all concentrations of any polymer whose wall shear stresses (or shear rates) were of the same magnitude at any given flow rate. In the dilute solutions a significant number of the effective molecules were degraded while in the more concentrated solutions, the same amount of degradation had a much smaller effect on the drag reducing capacity of the solutions"--Abstract, leaves i-iii.

Author : Aroon Shenoy
Publisher : Springer Nature
Page : 196 pages
File Size : 30,40 MB
Release : 2020-03-25
Category : Technology & Engineering
ISBN : 303040045X

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​This book explains theoretical derivations and presents expressions for fluid and convective turbulent flow of mildly elastic fluids in various internal and external flow situations involving different types of geometries, such as the smooth/rough circular pipes, annular ducts, curved tubes, vertical flat plates, and channels. Understanding the methodology of the analyses facilitates appreciation for the rationale used for deriving expressions of parameters relevant to the turbulent flow of mildly elastic fluids. This knowledge serves as a driving force for developing new ideas, investigating new situations, and extending theoretical analyses to other unexplored areas of the rheology of mildly elastic drag reducing fluids.The book suits a range of functions--it can be used to teach elective upper-level undergraduate or graduate courses for chemical engineers, material scientists, mechanical engineers, and polymer scientists; guide researchers unexposed to this alluring and interesting area of drag reduction; and serve as a reference to all who want to explore and expand the areas dealt with in this book.

Author : Hyunkook Shin
Publisher :
Page : 590 pages
File Size : 34,93 MB
Release : 1965
Category : Drag (Aerodynamics)
ISBN :

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The object of this thesis was to investigate the drag reduction phenomenon in turbulent flow caused by random coiling macromolecules in 'dilute' solution. In particular, this thesis was concerned with the relationship of drag (or its reduction) to the size of the coils and their concentration, of two kinds of polymers differing significantly in chain flexibility: polyethylene oxide (PEO), the more flexible, and polyisobutylene (PIB), the less flexible. It was found that, within any given homologous polymer series, the ability of macromolecules to reduce drag improved drastically with increasing molecular weight. That is, the concentration of polymers in solution either in the absolute weight fraction or in the effective volume fraction required to yield a given percent drag reduction decreased rapidly with increasing molecular weight. It was further found that there always existed an optimum concentration for any given polymer system at which the observed drag reduction reached a maximum.

Author : Charles Derick
Publisher :
Page : 88 pages
File Size : 43,83 MB
Release : 1973
Category : Channels (Hydraulic engineering)
ISBN :

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Two model open channel configurations (trapezoidal and rectangular) and three water soluble polymers (Polyox Coagulant, Polyox WSR-301, and Separan AP-30) were used to experimentally determine the effects of injecting dilute polymer solutions into open channel water flows. It was found that for all test cases, injection of the three polymer additives produced flow characteristic changes reflected as either a water surface level decrease at constant flow rates or a flow rate increase at constant static heads. These flow characteristic changes were found to be dependent, in varying degrees, on channel slope, surface roughness, injection point location, polymer injection method, flow Reynolds number, and injected polymer concentration.