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 Effects of Polymer Concentration on Turbulent Drag Reduction written by Chung Yin Leung and published by . This book was released on 2011 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Drag Reduction by Surfactant Additives written by Feng-Chen Li and published by John Wiley & Sons. This book was released on 2012-01-10 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent drag reduction by additives has long been a hot research topic. This phenomenon is inherently associated with multifold expertise. Solutions of drag-reducing additives are usually viscoelastic fluids having complicated rheological properties. Exploring the characteristics of drag-reduced turbulent flows calls for uniquely designed experimental and numerical simulation techniques and elaborate theoretical considerations. Pertinently understanding the turbulent drag reduction mechanism necessities mastering the fundamentals of turbulence and establishing a proper relationship between turbulence and the rheological properties induced by additives. Promoting the applications of the drag reduction phenomenon requires the knowledge from different fields such as chemical engineering, mechanical engineering, municipal engineering, and so on. This book gives a thorough elucidation of the turbulence characteristics and rheological behaviors, theories, special techniques and application issues for drag-reducing flows by surfactant additives based on the state-of-the-art of scientific research results through the latest experimental studies, numerical simulations and theoretical analyses. Covers turbulent drag reduction, heat transfer reduction, complex rheology and the real-world applications of drag reduction Introduces advanced testing techniques, such as PIV, LDA, and their applications in current experiments, illustrated with multiple diagrams and equations Real-world examples of the topic’s increasingly important industrial applications enable readers to implement cost- and energy-saving measures Explains the tools before presenting the research results, to give readers coverage of the subject from both theoretical and experimental viewpoints Consolidates interdisciplinary information on turbulent drag reduction by additives Turbulent Drag Reduction by Surfactant Additives is geared for researchers, graduate students, and engineers in the fields of Fluid Mechanics, Mechanical Engineering, Turbulence, Chemical Engineering, Municipal Engineering. Researchers and practitioners involved in the fields of Flow Control, Chemistry, Computational Fluid Dynamics, Experimental Fluid Dynamics, and Rheology will also find this book to be a much-needed reference on the topic.
Download or read book A Study of Molecular Parameters Influencing Polymer Drag Reduction written by Robert H. Wade and published by . This book was released on 1975 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of three molecular parameters on drag reduction were studied under turbulent-flow conditions. Drag reduction capability of linear polymers is altered by branching. Many short side chains decrease efficiency, while fewer but long branches increase it. The drag reduction of polyelectrolytes can be reversibly destroyed or enhanced by changes in configuration resulting from changes in pH or ionic strength or by complexing with counter-ion polyelectrolytes. Cross-linking can enhance or destroy the drag-reducing capability of a linear molecule, depending on the degree of cross-linking. Polymer degradation in turbulent flow is somewhat less in branched and cross-linked molecules than in linear ones.
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:
Download or read book Viscous Drag Reduction in Boundary Layers written by and published by AIAA. This book was released on 1990 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drag Reducing Polymer Molecular Weight Effects on Turbulent Diffusion for Uniformly Distributed Polymer Injection written by R. R. Walters and published by . This book was released on 1974 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of polymer molecular weight on turbulent diffusion and drag-reduction was investigated over a uniformly distributed polymer injection area. The purpose of the experiments, carried out in a porous wall pipe flow facility, was to determine optimum values of polymer molecular weight and injection mass flux for attaining maximum skin-friction reduction over a distributed injection area and to investigate associated turbulent diffusion characteristics. It was found for this type of polymer supply system, which provided polymer directly to the required wall shear stress region, that the optimum molecular weight was approximately an order of magnitude less than that normally used in skin-friction reduction applications with homogeneous solutions and localized injection ...Abstract, p. iii.
Download or read book Polymer Induced Drag Reduction Based on Stress Relaxation written by Susan Mary Lemke Penix and published by . This book was released on 1987 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of a Drag Reducing Polymer on the Turbulent Boundary Layer of a Submerged Flat Plate written by Stanley M. Kumor and published by . This book was released on 1973 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of an experimental investigation was to study the effect that a drag-reducing polymer has on the turbulent boundary layer of a submerged flat plate using a Laser-Doppler flowmeter. Data are presented showing the time effects caused by polymer solution drag-reduction degradation on the mean velocity and axial fluctuating-velocity profiles. The importance of the data is that it provides a connection between the apparently diverse results reported previously for the velocity profiles at conditions of high and low drag-reduction effectiveness. The polymer molecules' effect on the boundary layer structure is apparently progressively restricted to the near wall region with decreasing drag reduction in agreement with the mean velocity profiles. (Author).
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 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 Comparative Effects of Drag Reducing Polymers An Experimental Report written by and published by . This book was released on 1992 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The experiments described in this report were performed within the framework of the overall ASTI Team effort in polymer science. The underlying predicate of this program has been to achieve a basis for understanding the shear viscosity of dilute polymer solutions through a detailed description of the molecular interactions. Interaction descriptions must include water/polymer, water/surface and polymer/surface contributions to provide understanding of the mechanisms determining the shear viscosity and related noise and drag reduction effects. Although certain anionic polymeric drag reduction effects observed herein are not dramatic compared to those achieved with the standard polyethylene-oxide, these types of polymers offer the potential for drastically altering the interaction between the surface and adjacent layers of water molecules. It can be assumed that the water layer/surface interaction is dependent on the nature of the surface potential and the presence of strongly interacting species in that region. Thus, any mechanism reducing the concentration of such active species near the surface should reduce the overall strength of the interaction. However, drag reduction actually increased for polyacrylamide changing from deionized water to 'instant ocean' (salt water environment). This suggests the role of ions in determining polymer effectiveness may be complex.
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Drag Reduction and Degradation Effects of a Polymer Solution written by D. J. Harris and published by . This book was released on 1968 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Influence of Polymer Additives on Velocity and Temperature Fields written by Bernhard Gampert and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Symposium on "The Influence of Polymer Additives on Veloc ity and Temperature Fields" was proposed to the General Assem bly of the International Union of Theoretical and Applied Me chanics (IUTAM) by the "Gesellschaft fur Angewandte Mathematik und Mechanik" (GAMM). The Symposium was held under the auspices of IUTAM in association with the "Deutsche Rheologische Ge sellschaft" (DRG) with responsibility for the organization ly ing with B. Gampert (Universitat-GH-Essen). The main aim of this IUTAM Symposium was to consider the funda mental aspects of the phenomena that occur when small amounts of polymers are added to turbulent flows (turbulent drag re duction) and laminar porous media flows. In particular atten tion was devoted to - the influence of molecular parameters of the polymers and solution properties, especially the elongational viscosity, on turbulent flow and laminar porous media flow; the influence of polymers on the turbulence structure in polymer drag reduction
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:
