Download or read book Surfactant Drag Reduction Using Mixed Counterions written by Diana Snelling and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This study focused on using mixtures of counterions to improve the performance of a cationic surfactant over single counterions. The concentration of surfactant and total counterion concentration remained constant while the ratio of each counterion was varied. The cationic surfactant cetyltrimethylammonium chloride (CTAC) was tested with counterions sodium ethylbenzenesulfonate (NaEbs), sodium 3-hydroxy-2-naphthoate (SHN), and sodium salicylate (NaSal). Organic counterions stabilize threadlike micelles in surfactant solutions and enable turbulent drag reduction. Cryo-TEM imaging was used to visualize the nanostructures of our complex fluids. Counterion mixtures were tested in both water and ethylene glycol/water solutions. Certain ratios of counterions resulted in increased maximum drag reduction and effective temperature range compared with either counterion at the same total counterion concentration. The aqueous system of 75% NaSal and 25% SHN gave effective drag reduction over the entire temperature range of our testing system (2-95°C). This surfactant system is a candidate for use in conventional aqueous district cooling and in aqueous district heating systems. Surfactant solutions with mixed counterions in 20% ethylene glycol/water showed the same pattern of behavior as in water but with less effective drag reduction. Lower effective upper temperatures and lower maximum drag reductions were found in the 20% EG/water solvent.
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 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 Drag Reduction Using Mixed Solutions of Surfactant and Hydrotrope written by Subbarao Chirravuri and published by . This book was released on 2013-09-21 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies on the Nanostructure Rheology and Drag Reduction Characteristics of Drag Reducing Cationic Surfactant Solutions written by Wu Ge and published by . This book was released on 2008 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: At concentrations above CMC (critical micellization concentration) or temperatures above CMT (critical micellization temperature) surfactant molecules dissolved in aqueous solution self-assemble into colloidal aggregates such as micelles or vesicles. These colloidal aggregates vary in shape and size depending on a number of system conditions such as surfactant molecular structure, surfactant concentration, salt concentration, temperature, etc. Among the variety of micellar structures in solution, wormlike micelles resembling the long chain molecules of high polymers may reduce friction energy loss in turbulent flow by up to 90% at relatively low surfactant concentrations under appropriate flow and temperature conditions. This phenomenon is termed drag reduction (by surfactant additives) and it has significant potential impacts on fluid transport and on the environment. Among surfactant drag reducing additives, cationic surfactants with organic counterions have received the most attention in the past two decades mainly because of their excellent drag reducing ability, broad availability, low concentration requirements and general insensitivity to ionic metal impurities. Typical cationic surfactants studied for drag reduction are quaternary ammonium salts with one long alkyl chain (carbon number from 14 to 22) and methyl or hydroxyethyl groups in the other positions. They are, however, mildly toxic with poor biodegradability, so there is a need to develop more environmentally friendly surfactant drag reducing additives. Other types of surfactants such as anionics, zwitterionics and nonionics have also been studied. To obtain desired drag reducing properties, previous research has been focused on utilizing synergistic effects that may arise when two surfactant species are mixed. Mixed surfactant systems studied for drag reduction included cationic surfactants of mixed alkyl chain lengths, cationic/anionic, nonionic/nonionic, nonionic/anionic and zwitterionic/anionic surfactant mixtures in aqueous solutions and in water/co-solvent systems. Organic counterions added to dilute cationic surfactant aqueous solutions are effective in inducing and stabilizing wormlike micelle formation at relatively low counterion to surfactant molar ratios, thereby promoting their drag reducing effectiveness. The interactions of the cationic surfactant and organic counterion can be enhanced by tuning either or both of them, structurally and/or by concentration and molar ratio, to tailor-make highly efficient drag reducing systems suitable for different applications. Understanding the important role of organic counterions in the dynamics of the formation of cationic surfactant wormlike micelles and their networks is important. In this work, investigations have been conducted in how changes in the organic counterion chemical structure of a series of p-halobenzoates and counterion to surfactant ratio affect zeta potential, nanostructure, drag reduction and rheological properties. Also, certain mixed aromatic counterion systems were studied which showed excellent synergistic effects on promoting wormlike micellar branched networks and enhancing drag reducing effectiveness. In this work, an enclosed rotating disk apparatus was designed and constructed for screening novel surfactant species synthesized in chemistry laboratories. After correlating its drag reducing results with those obtained through the conventional pipe flow test system, this small scale apparatus is capable of testing materials for drag reduction effectiveness independently. A long range goal of this research is to develop effective low concentration surfactant systems with good drag reduction effectiveness. Guided by the correlations and understandings obtained in the past research, in this work, a number of new surfactants or counterions were selected or synthesized for exploratory drag reduction tests.
Download or read book Interactions Between Drag Reducing Polymers and Surfactants written by Ketan Prajapati and published by . This book was released on 2009 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drag reduction in turbulent pipe flow using polymeric and surfactant additives is well known. Although extensive research work has been carried out on the drag reduction behavior of polymers and surfactants in isolation, little progress has been made on the synergistic effects of combined polymers and surfactants. In this work the interactions between drag-reducing polymers and surfactants were studied. The drag-reducing polymers studied were nonionic polyethylene oxide (referred to as PEO) and anionic copolymer of acrylamide and sodium acrylate (referred to as CPAM). The drag-reducing surfactants studied were nonionic ethoxylated alcohol - Alfonic 1412-7 (referred to as EA), cationic surfactant - Octadecyltrimethylammonium chloride in pure powder form (referred to as OTAC-p) and commercial grade cationic surfactant - Octadecyltrimethylammonium chloride in isopropanol solvent - Arquad 18-50 (referred to as OTAC-s). The interactions between polymers and surfactant were reflected in the measurements of the physical properties such as electrical conductivity, surface tension, viscosity and turbidity. The critical micelle concentration (cmc) of the mixed polymer / surfactant system was found to be different from that of the surfactant alone. The viscosity of a polymer solution was significantly affected by the addition of surfactant. Weak interactions were observed for the mixed systems of nonionic polymer - nonionic surfactant and anionic polymer - nonionic surfactant. Due to the wrapping of polymer chains around the developing micelles, a minimum in the viscosity is observed in these two cases. In the case of nonionic polymer / cationic surfactant system, the change in the viscosity was found to depend on the polymer concentration (C) and the critical entanglement concentration (C*). When the polymer concentration (C) was less than C* (C C*), the plot of the viscosity versus surfactant concentration exhibited a minimum. When C C*, a maximum in the viscosity versus surfactant concentration plot was observed. The interactions between nonionic polymer and cationic surfactant were observed to increase with the increase in temperature. A large drop in the viscosity occurred in the case of anionic-polymer / cationic-surfactant system when surfactant was added to the polymer solution. The observed changes in the viscosity are explained in terms of the changes in the extension of polymeric chains resulting from polymer-surfactant interactions. The anionic CPAM chains collapsed upon the addition of cationic OTAC-p, due to charge neutralization. The presence of counterion sodium salicylate (NaSal) stabilized the cationic surfactant monomers in the solution, resulting in micelle formation at a surfactant concentration well below the concentration where complete charge neutralization of anionic polymer occurred. Preliminary results are reported on the pipeline drag reduction behavior of mixed polymer-surfactant system. The results obtained using combinations of CPAM / OTAC-p in pipeline flow are found to be in harmony with the interaction study. Due to the shrinkage of CPAM chains upon the addition of OTAC-p, the drag reducing ability of CPAM is compromised.
Download or read book Investigations on Drag Reduction by Interactions Between Polymer and Surfactant and Polymer and Polymer written by Jia Yang and published by . This book was released on 2015 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large amount of studies have been carried out on pipeline flow with several kinds of drag reducing agents, especially polymers and surfactants. Drag reducing agents, by definition, are additives which help suppress or eliminate turbulence in a pipeline. The mechanism and methodology of polymer only or surfactant only as drag reducing additives have been fully discovered. Whether mixed drag reducers such as polymer-surfactant or polymer-polymer systems would be effective is still not clear. In our study, polymer-surfactant and polymer-polymer mixed additives are used in order to explore the synergistic effects and interactions in pipeline flow loops. The experimental work was divided into two sections: bench-scale experiments and pilot-scale experiments. In bench-scale experiments, the properties of prepared fluids such as, surface tension, conductivity and shear viscosity were measured. Several comparison methods and calculations were applied to give better understandings of the properties resulting from mixing of polymer with surfactant and polymer with polymer. After analysis of the properties, several combinations of concentrations were selected and solutions were prepared in the main tank of pilot plant and pumped into the pipeline set-up to test the pipeline flow behaviors. Turbulence structure/Reynolds number, pipe diameter, polymer-surfactant concentration were all considered as influencing factors. Critical micelle concentration, critical aggregation concentration, polymer saturation point, the onset of drag reduction, and the interactions between the mixed additives were discussed. A comparison between pipeline results and the predictions of Blasius Equation or Dodge-Metzner Equation were also discussed.. For polymer-surfactant studies, a commonly used polymer additive - carboxylmethylcellulose (referred to as CMC which is anionic) was selected as the drag reducing agent. The performance of this polymer was investigated in the presence of six surfactants respectively - Alcohol ethoxylate (referred to as Alfonic 1412-9 and Alfonic 1412-3 which are nonionic), Aromox DMC (nonionic surfactant), Stepanol WA-100 and Stepwet DF-95 (which mainly consist sodium lauryl sulfates, anionic surfactant) and Amphosol (which is zwitterionic).The experiments were first conducted with pure CMC solution with different concentrations (100ppm, 500ppm, 700ppm and 1000ppm) as a standard. The 500ppm CMC solution was selected as the best polymer concentration with highest drag reduction efficiency. For polymer-surfactant combinations, CMC-Alfonic 1412-9, CMC-Alfonic1412-3, CMC-Stepanol and CMC-Stepwet systems were found to have significant interactions. High surfactant concentration resulted in reduction in %DR. The addition of Aromox increased the drag reduction ability and onset point when concentration was higher than the polymer saturation points. Also, both hydrophobic and electrostatic interactions were thought to have an effect on critical micelle concentration, which led to the fluctuations in the %DR. For polymer-polymer studies, PAM-PEO system at two different polymer concentrations were investigated. Overall, Pure PAM solution had much higher drag reduction ability than pure PEO solutions. Mixing them together, strong interactions occurred when PEO fraction was high (over 50%) which affected %DR and shear viscosity substantially. Power-law constants n and k were also taken into account and found to exhibit opposite trends with the increase of PEO fraction.
Download or read book Polymer Physics written by Leszek A. Utracki and published by John Wiley & Sons. This book was released on 2011-02-14 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a comprehensive review of the state-of-the-art advanced research in the field, Polymer Physics explores the interrelationships among polymer structure, morphology, and physical and mechanical behavior. Featuring contributions from renowned experts, the book covers the basics of important areas in polymer physics while projecting into the future, making it a valuable resource for students and chemists, chemical engineers, materials scientists, and polymer scientists as well as professionals in related industries.
Download or read book Nuclear Magnetic Resonance written by Jacek Wojcik and published by Royal Society of Chemistry. This book was released on 2013-03-21 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applications of Nuclear Magnetic Resonance (NMR) span a wide range of scientific disciplines, including physis, biology and medicine. Each volume in this series comprises a combination of reports offering a comprehensive coverage of the literature. With an unrivalled scope of coverage, this Specialist Periodical Report presents an invaluable source of current methods and applications for seasoned practitioners and newcomers alike.
Download or read book Specialist Surfactants written by I.D. Robb and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surfactants are vital components in biological systems, are key ingredients in many formulated products and play an important role in many industrial processes. The property which makes surfactants so useful is their ability to stabilize complex colloidal and interfacial systems. It is not surprising therefore that many new surfactant materials are developed, many of which have novel properties. However because their potential is not fully appreciated they remain underutilized by industry. The main purpose of this book is to illustrate the utility of a range of novel surfactants, in particular those which have been found useful in specific areas and which seem to offer promise across a wider range of applications. The contributors are drawn from industry and academic research and provide a comprehensive account of the preparation, properties and applications of these specialist surfactants. Research chemists in industry and academia will find this book a concise and authoritative account of this important group of surfactants.
Download or read book The Effect of Chemical Structures of Cationic Surfactants Or Counterions on Solution Drag Reduction Effectiveness Rheology and Micellar Microstructure written by Zhiqing Lin and published by . This book was released on 2000 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drag Reduction in Pipeline by Polymer surfactant and Polymer polymer Mixtures written by Weicong Huang and published by . This book was released on 2015 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive researches have been conducted to investigate into the drag reduction behavior of the polymer-surfactant mixture and the polymer-polymer mixture. The drag reduction effect of PAM (polyacrylamide), PEO (polyethylene oxide) and CMC (carboxymethyl cellulose) has already been studied respectively. However, the drag reduction effects of the combination of these polymers have not been studied before. It is interesting to investigate into these combinations because the synergy between different polymers can enhance the drag reduction effect under the right condition. SDS (sodium dodecyl sulfate) is a surfactant widely used in many commercially available detergents. When dissolved in water and circulated in the flow loop, the drag reduction effect of SDS has also been observed. Therefore, the combination of PAM and SDS is also worth exploring. The synergy between the polymer and the surfactant may strengthen the drag reduction effect. In this thesis, the drag reduction effects are investigated for the following combinations: the PAM-SDS system, the PAM-CMC system and the PEO-CMC system. The mixed solutions are circulated in the flow loop, where the pressure drop over a certain distance and the flow rate are recorded in order to plot the friction factor against the Reynolds number. In addition, the viscosity, conductivity and surface tension of the mixed solutions are studied at bench-scale to look for the synergy in the mixed system.
Download or read book Drag Reduction of Turbulent Flows by Additives written by A. Gyr and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drag Reduction of Turbulent Flows by Additives is the first treatment of the subject in book form. The treatment is extremely broad, ranging from physicochemical to hydromechanical aspects. The book shows how fibres, polymer molecules or surfactants at very dilute concentrations can reduce the drag of turbulent flow, leading to energy savings. The dilute solutions are considered in terms of the physical chemistry and rheology, and the properties of turbulent flows are presented in sufficient detail to explain the various interaction mechanisms. Audience: Those active in fundamental research on turbulence and those seeking to apply the effects described. Fluid mechanical engineers, rheologists, those interested in energy saving methods, or in any other application in which the flow rate in turbulent flow should be increased.
Download or read book Wormlike Micelles written by Cecile A Dreiss and published by Royal Society of Chemistry. This book was released on 2017-03-21 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wormlike Micelles describes the latest developments in the field including new systems, characterization and applications.
Download or read book Previews of Heat and Mass Transfer written by and published by . This book was released on 1993 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Correlations Among Surfactant Drag Reduction Additive Chemical Structures Rheological Properties and Microstructures in Water and Water co solvent Systems written by Ying Zhang and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Under appropriate conditions, surfactants in water are known to self-assemble into threadlike micelles which reduce the drag of the solution in turbulent flow compared to that of the water solvent at the same flow rate. The phenomenon is called turbulent drag reduction (DR). Using surfactant DR additives (DRA) can save up to 70% pumping energy in turbulent pipe flow water circulating systems, such as district cooling/heating systems, in which a large amount of water is temperature controlled in a central station and recirculated within a district to heat/cool the buildings therein. A new approach to energy saving in district cooling systems is to replace water with 20% ethylene glycol (EG) in water as the cooling medium, which can be cooled down to -5°C (compared to 5°C for water). The coolant typically warms up to 15°C and is then returned to the central station for recooling. The temperature difference for the 20%EG/W medium is 20°C ( -5°C to 15°C), twice as much as the 10°C for water (5°C to 15°C), increasing its cooling capacity and reducing the amount of recirculating coolant and pumping energy needed by about 50%. Pumping energy could be reduced by an additional 50% if effective surfactant DRAs can be used in such mixed solvents. However, co-solvents such as EG are known to inhibit micelle formation which may decrease the effectiveness of DRAs compared to pure water systems. This study investigated and developed effective surfactant DRAs in several water/co-solvent systems at low temperatures. DR, rheological, cryogenic transmission electron microscopy (cryo-TEM) and 1H NMR experiments are being carried out to develop correlations among DR, rheological properties and micelle microstructures. In addition to the practical application in district cooling systems using EG-water mixed solvent or other co-solvent systems, the results of this study provide more fundamental understanding of the effects of solvent properties on threadlike micelle microstructure, drag reduction and system rheology, which are poorly understood now.
Download or read book Nuclear Magnetic Resonance written by G A Webb and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a spectroscopic method, Nuclear Magnetic Resonance (NMR) has seen spectacular growth over the past two decades, both as a technique and in its applications. Today the applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules which is covered in two reports: "NMR of Proteins and Acids" and "NMR of Carbohydrates, Lipids and Membranes". For those wanting to become rapidly acquainted with specific areas of NMR, this title provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an in valuable source of current methods and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.
