Download or read book Effect of Polymer Coiling on Drag Reduction written by and published by . This book was released on 1966 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book Drag Reduction Onset for a Random Coil Polymer written by John Wah Yuk Yuen and published by . This book was released on 1976 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Polymer Structure on Drag Reduction in Nonpolar Solvents written by Gin Chain Liaw and published by . This book was released on 1968 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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.
Download or read book Rheology of Drag Reducing Fluids written by Aroon Shenoy and published by Springer Nature. This book was released on 2020-03-25 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Drag Reduction in Flow of Dilute Polymer Solutions written by James Henry Hand and published by . This book was released on 1971 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reduction of Drag in Turbulence by Dilute Polymer Solutions written by Hyunkook Shin and published by . This book was released on 1965 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Control of Sewer Overflows by Polymer Injection written by R. W. Chandler and published by . This book was released on 1977 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymer Adsorption in Laminar Tube Flow of Drag Reducing Fluids written by Jae Ek Son and published by . This book was released on 1978 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NBS Special Publication written by and published by . This book was released on 1918 with total page 1164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Polymer Parameters on Drag Reduction written by Abbas Mohammad Safieddine and published by . This book was released on 1990 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Polymer Concentration and Tube Diameter on Drag Reduction Resulting from High Molecular Weight Additives in Water written by Jerald Paul Peterson and published by . This book was released on 1970 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Augmenting Effects of Additives on Open Channel Flows written by Charles Derick and published by . This book was released on 1973 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Transient Aspects of the Polymer Induced Drag Reduction Phenomenon written by Anselmo Soeiro Pereira and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The addition of a small amount of polymers of high molecular weight can lead to a pressure drop decrease in turbulent flows. The polymers successively stretch and coil by interacting with the turbulent structures, which imposes a transient behaviour on the drag reduction (DR). As a result, DR undergoes three stages over time: A, B, and C. In stage A, DR departs from zero and assumes negative values due to a significant polymer stretching at the beginning of the process, which requires energy from the flow. After the minimum DR is reached, the polymers start their coil-stretch cycle and DR increases in response to the development of turbulent structures, achieving a maximum value, which makes for the beginning of stage B. However, during their coil-stretch cycle, polymers can be mechanically degraded as a result of an intense polymer stretching, which reduces their ability to act as energy exchange agents. Hence, when polymer degradation becomes pronounced, DR decreases until achieving a final value. The polymer degradation process characterizes the stage C. In the present work, numerical analyses are conducted aiming to investigate the stages A, B and C. The transient aspects of the polymer induced drag reduction phenomenon are explored with the aid of direct numerical simulations of turbulent plane Poiseulle and Couette flows of viscoelastic FENE-P fluids taking into account a large range of Reynolds number, Weissenberg number and maximum polymer molecule extensibility. Stages A and B are carefully studied from tensor, energy budget and spectral perspectives. A polymer scission model is developed in order to numerically reproduce the stage C.
Download or read book Turbulent Drag Reduction by Polymers Surfactants and Their Mixtures in Pipeline Flow written by Ali Asghar Mohsenipour and published by . This book was released on 2011 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lthough extensive research work has been carried out on the drag reduction behavior of polymers and surfactants alone, little progress has been made on the synergistic effects of combined polymers and surfactants. A number of studies have demonstrated that certain types of polymers and surfactants interact with each other to form surfactant-polymer complexes. The formation of such complexes can cause changes in the solution properties and may result in better drag reduction characteristics as compared with pure additives. A series of drag-reducing surfactants and polymers were screened for the synergistic studies. The following two widely used polymeric drag reducing agents (DRA) were chosen: a copolymer of acrylamide and sodium acrylate (referred to as PAM) and polyethylene oxide (PEO). Among the different types of surfactants screened, a cationic surfactant octadecyltrimethylammonium chloride (OTAC) and an anionic surfactant Sodium dodecyl sulfate (SDS) were selected for the synergistic study. In the case of the cationic surfactant OTAC, sodium salicylate (NaSal) was used as a counterion. No counterion was used with anionic surfactant SDS. The physical properties such as viscosity, surface tension and electrical conductivity were measured in order to detect any interaction between the polymer and the surfactant. The drag reduction (DR) ability of both pure and mixed additives was investigated in a pipeline flow loop. The effects of different parameters such as additive concentration, type of water (deionized (DI) or tap), temperature, tube diameter, and mechanical degradation were investigated. The addition of OTAC to PAM solution has a significant effect on the properties of the system. The critical micelle concentration (CMC) of the mixed surfactant-polymer system is found to be different from that of the surfactant alone. The anionic PAM chains collapse upon the addition of cationic OTAC and a substantial decrease in the viscosity occurs. The pipeline flow behaviour of PAM/OTAC mixtures is found to be consistent with the bench scale results. The drag reduction ability of PAM is reduced upon the addition of OTAC. At low concentrations of PAM, the effect of OTAC on the drag reduction behavior is more pronounced. The drag reduction behavior of polymer solutions is strongly influenced by the nature of water (de-ionized or tap). The addition of OTAC to PEO solution exhibited a week interaction based on the viscosity and surface tension measurements. However, the pipeline results showed a considerable synergistic effect, that is, the mixed system gave a significantly higher drag reduction (lower friction factors) as compared with the pure additives (pure polymer or pure surfactant). The synergistic effect in the mixed system was stronger at low polymer concentrations and high surfactant concentrations. Also the resistance against mechanical degradation of the additive was improved upon the addition of OTAC to PEO. The mixed PEO/SDS system exhibited a strong interaction between the polymers (PEO) and the surfactant (SDS), Using electrical conductivity and surface tension measurements, the critical aggregation concentration (CAC) and the polymer saturation point (PSP) were determined. As the PEO concentration is increased, the CAC decreases and the PSP increase. The addition of SDS to the PEO solution exhibits a remarkable increase in the relative viscosity compared to the pure PEO solution. This increase is attributed to the changes in the hydrodynamic radius of the polymer coil. The pipeline flow exhibited a considerable increase in DR for the mixed system as compared to the pure PEO solution. The addition of surfactant always improves the extent of DR up to the PSP. Also the mixed PEO/ SDS system shows better resistance against shear degradation of the additive.
Download or read book Report written by United States. National Bureau of Standards and published by . This book was released on 1968 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Solvent Viscosity on Polymer Drag Reduction written by Larry Gregg Chorn and published by . This book was released on 1975 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Viscous Drag Reduction written by C. Sinclair Wells and published by Springer. This book was released on 2013-12-20 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt:
