Download or read book Polymer Chain Scission in Extensional and Turbulent Flows and Implications for Friction Drag Technologies written by Siva A. Vanapalli and published by . This book was released on 2006 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Applied Polymer Processing Technology written by Nicholas P. Cheremisinoff and published by CRC Press. This book was released on 2020-10-07 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Offers detailed coverage of applied polymer processing--presenting a wide range of technologies and furnishing state-of-the-art data on polymer components, properties, and processibility. Reviews fundamental rheological concepts. Contains over 1600 bibliographic citations, some 450 equations, and over 400 tables, drawings, and photographs."
Download or read book Chain Scission in Turbulent Flow of Dilute Polymer Solutions written by Brian G. Price and published by . This book was released on 2002 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flexible Polymer Chains in Elongational Flow written by Tuan Q. Nguyen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of polymer solutions in simple shear flows has been the subject of considerable research in the past. On the other hand, reports on polymers in elongational flow have appeared comparatively recently in the literature. Elongational flow with an inherent low vorticity is known to be more effective in extending polymer chains than simple shear flow and thus is more interesting from the point of view of basic (molecular chain dynamics at high deformation) and applied polymer science (rheology, fiber extrusion, drag reduction, flow through porous media). Undoubtly, one landmark in the field of polymer dynamics in elongational flow was the notion of critical strain-rate for chain extension, initially put forward by A. Peterlin (1966) and later refined into the "coil-stretching" transition by P. G. de Gennes and H. Hinch (1974). In the two decades which followed, significant progress in the understanding of chain conformation in "strong" flow has been accomplished through a combination of advances in instrumentation, computation techniques and theoretical studies. As a result of the multidisciplinary nature of the field, information on polymer chains in "strong" flow is accessible only from reviews and research papers scattered in disparate scientific journals. An important objective of this book is to remedy that situation by providing the reader with up-to-date knowledge in a single volume. The editors therefore invited leading specialists to provide both fundamental and applied information on the multiple facets of chain deformation in elongational flow.
Download or read book Analytical and Experimental Study of Turbulent Flow Drag Reduction and Degradation with Polymer Additives written by Xin Zhang and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow friction reduction by polymers is widely applied in the oil and gas industry for flow enhancement or to save pumping energy. The huge benefit of this technology has attracted many researchers to investigate the phenomenon for 70 years, but its mechanism is still not clear. The objective of this thesis is to investigate flow drag reduction with polymer additives, develop predictive models for flow drag reduction and its degradation, and provide new insights into the drag reduction and degradation mechanism. The thesis starts with a semi-analytical solution for the drag reduction with polymer additives in a turbulent pipe flow. Based on the FENE-P model, the solution assumes complete laminarization and predicts the upper limitation of drag reduction in pipe flows. A new predictive model for this upper limit is developed considering viscosity ratios and the Weissenberg number - a dimensionless number related to the relaxation time of polymers. Next, a flow loop is designed and built for the experimental study of pipe flow drag reduction by polymers. Using a linear flexible polymer - polyethylene oxide (PEO) - in water, a series of turbulent flow experiments are conducted. Based on Zimm's theory and the experimental data, a correlation is developed for the drag reduction prediction from the Weissenberg number and polymer concentration in the flow. This correlation is thoroughly validated with data from the experiments and previous studies as well. To investigate the degradation of drag reduction with polymer additives, a rotational turbulent flow is first studied with a double-gap rheometer. Based on Brostow's assumption, i.e., the degradation rate of drag reduction is the same as that of the molecular weight decrease, a correlation of the degradation of drag reduction is established, along with the proposal of a new theory that the degradation is a first-order chemical reaction based on the polymer chain scission. Then, the accuracy of the Brostow's assumption is examined, and extensive experimental data indicate that it is not correct in many cases. The degradation of drag reduction with polymer additives is further analyzed from a molecular perspective. It is found that the issue with Brostow's theory is mainly because it does not consider the existence of polymer aggregates in the flow. Experimental results show that the molecular weight of the degraded polymer in the dilute solution becomes lower and the molecular weight distribution becomes narrower. An improved mechanism of drag reduction degradation considering polymer aggregate is proposed - the turbulent flow causes the chain scission of the aggregate and the degraded aggregate loses its drag-reducing ability. Finally, the mechanism of drag reduction and degradation is examined from the chemical thermodynamics and kinetics. The drag reduction phenomenon by linear flexible polymers is explained as a non-spontaneous irreversible flow-induced conformational-phase-change process that incorporates both free polymers and aggregates. The entire non-equilibrium process is due to the chain scission of polymers. This theory is shown to agree with drag reduction experimental results from a macroscopic view and polymer behaviours from microscopic views. The experimental data, predictive models, and theories developed in this thesis provide useful new insights into the design of flow drag reduction techniques and further research on this important physical phenomenon.
Download or read book Crosslinking and Scission in Polymers written by O. Güven and published by Springer Science & Business Media. This book was released on 1990-01-31 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute on Advanced Methods of Determination of Crosslinking and Scission in Polymers and Their Effects on Mechanical Properties, Kemer-Antalya, Turkey, September 4-16, 1988
Download or read book Polymers and Plastrons written by Anoop Rajappan and published by . This book was released on 2020 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frictional energy dissipation in wall-bounded turbulence is ubiquitous in modern engineering systems, ranging from the flow of liquids through pipelines, to the drag-inducing boundary layer around ships and submarines. The effective mitigation of this frictional drag is therefore of great practical interest, and offers substantial economic and environmental benefits. This thesis focuses on two complementary techniques for turbulent drag reduction--the active injection of polymers into the flow, and the passive aerophilic texturing of the wall--and aims to address practical challenges that prevent their widespread adoption in real-life systems, with an emphasis on marine applications. The prohibitive cost of synthetic polymers remains a key impediment to their large-scale deployment in commercial marine operations. This thesis hence focuses on affordable and readily accessible sources of high molecular weight biopolymers: specifically, the water-soluble fiber, or mucilage, extracted from seeds such as flax, chia and psyllium. By means of frictional drag measurements inside a bespoke Taylor-Couette apparatus, seed mucilage is shown herein to display drag reduction efficacy and flow longevity comparable to common synthetic polymers, while offering significant advantages in terms of raw material cost and biodegradability. Preliminary investigations confirm that oil-soluble natural polymers, such as rubber latex, can analogously be employed as eco-friendly drag reducers for the transport of hydrocarbon feedstocks. Superhydrophobic texturing of submerged flow boundaries has emerged recently as another viable method of drag reduction in aqueous flows. Despite sustained research interest in both polymers and superhydrophobic walls as standalone methods for drag mitigation, attempts to employ them jointly has remained unsuccessful. In this thesis, cooperative drag reduction effects are explored for two common drag-reducing polymers, paired with regularly patterned as well as randomly textured superhydrophobic walls. Dissolved flexible macromolecules are shown to act in concert with the slip-inducing air layer, or plastron, trapped atop the superhydrophobic texture, yielding enhanced reductions in turbulent drag greater than that achievable from either method employed independently. An additive law in Prandtl-von Kármán coordinates is derived that accurately predicts this combined effect at dilute polymer concentrations, and the adverse influence of the surface activity of polymers on wall slip is also elucidated.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1995 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drag Reduction in Turbulent Flow of Polymer Solutions written by Edward W. Merrill and published by . This book was released on 1975 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Various Aspects of Polymer Induced Drag Reduction in Turbulent Flow written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Extensional Flow Behavior of Turbulent Drag Reducing Polymer Solutions written by Jay Anderson Shands and published by . This book was released on 1985 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymeric Materials Encyclopedia Twelve Volume Set written by Joseph C. Salamone and published by CRC Press. This book was released on 2020-07-17 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Polymeric Materials Encyclopedia presents state-of-the-art research and development on the synthesis, properties, and applications of polymeric materials. This groundbreaking work includes the largest number of contributors in the world for a reference publication in polymer science, and examines many fields not covered in any other reference. With multiple articles on many subjects, the encyclopedia offers you a broad-based perspective on a multitude of topics, as well as detailed research information, figures, tables, illustrations, and references. Updates published as new research unfolds will continue to provide you with the latest advances in polymer science, and will keep the encyclopedia at the forefront of the field well into the future. From novices to experienced researchers in the field, anyone and everyone working in polymer science today needs this complete assessment of the state of the art. The entire 12-volume set will be available in your choice of printed or CD-ROM format.
Download or read book Advances in Polymer Materials and Technology written by Anandhan Srinivasan and published by CRC Press. This book was released on 2016-08-19 with total page 1088 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers recent advancements in the field of polymer science and technology. Frontiers areas, such as polymers based on bio-sources, polymer based ferroelectrics, polymer nanocomposites for capacitors, food packaging and electronic packaging, piezoelectric sensors, polymers from renewable resources, superhydrophobic materials and electrospinning are topics of discussion. The contributors to this book are expert researchers from various academic institutes and industries from around the world.
Download or read book On the Simulation and Theory of Polymer Dynamics in Sieving Media written by Martin Kenward and published by . This book was released on 2007 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Studies on the Physics and Technology of Polymer Drag Reduction written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies of polymer drag-reduction were carried out in the laboratory of Thomas J. Hanratty. Companion studies were carried out in the polymer laboratory of Anthony J. McHugh so that the performance of drag-reducing polymer solutions can be related to their rheological and rheo-optical properties in simple non-turbulent flows. The work was influenced by the notion that aggregation of polymer molecules could be an important role. A remarkable finding is that molecular weight and molecular weight distribution need not change as the drag-reducing ability of the polymer solution degraded. Rheo-optical studies in a Couette device showed that effective polymer solutions develop turbidity over a range of shear rates characteristic of those used in the flow loop. This study shows that the drag reduction can be enhanced by using mixing and delivery procedures which enhance the formation aggregates.
Download or read book Effect of Dilute Polymer Solutions on the Turbulence Characteristics and the Frictional Drag of External Flows written by T. Kowalski and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
