Download or read book Heat Transfer Enhancement in Turbulent Drag Reducing Surfactant Solutions written by Andrew J. Maxson and published by . This book was released on 2017 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the second study, the behavior of a mixed cationic / zwitterionic drag reducing surfactant system was explored. Precipitation of the solution into surfactant-rich and water-rich phases was observed under certain conditions, and this behavior was found to be extremely sensitive to composition, temperature, and shear. A heat transfer enhancement scheme exploiting the phase behavior was successfully demonstrated in which heat transfer reduction was eliminated while drag reduction performance was maintained.

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 Study of Heat Transfer Enhancement of Drag Reducing Surfactant Solutions Through the Use of Static Mixers written by James Courtney Knight and published by . This book was released on 2009 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Drag reduction is the phenomenon in which adding a small amount of a chemical additive to a flowing fluid reduces the friction factor of the turbulent flow. Drag reducing agents can lead to reduced pumping energy requirements, fewer pumps required, or smaller pumps, all of which translate into reduced operating and/or capital costs; however, there is a corresponding reduction in heat transfer as well. The goal of this research was to investigate whether the addition of static mixers to a surfactant drag reducing solution would enhance heat transfer in a tube-in-tube heat exchanger. Drag reduction and heat transfer tests were run in a pipe flow system under various conditions. The variables were the primary loop fluid, the primary loop temperature, the Reynolds number, and the length of static mixer at the entrance to the main heat exchanger. Calculations were performed on the data to determine the friction factor, percent drag reduction, amount of heat transferred, inner wall heat transfer coefficient, and Nusselt number for each of the experimental runs. After analyzing the data, it was clear that the surfactant solution was able to reassemble its micellar structure after being degraded by the static mixers. The addition of static mixers improved the heat transfer by 55%-400%. Lengthening the static mixer did not cause a significant increase in heat transfer properties, but it did cause a much larger pressure drop penalty.

Download or read book Studies in Heat Transfer Enhancement in Drag Reducing Solutions written by Ross Bradley Chongson and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drag reduction (DR) by additives typically involves the use of either high molecular weight polymer or surfactants, and can reduce turbulent pressure losses in pipes by up to 90%. These additives, particularly high polymers, have seen considerable use in increasing the throughput of crude oil pipelines. Surfactant additives, while even more effective than their polymer cousins, have not seen widespread adoption despite their applicability to recirculating district heating or cooling networks. Due to their effects on the turbulent structure of pipe flow, drag reducing additives also result in the loss of radial mixing, and thus the suppression of convective heat transfer. This is referred to as the 'heat transfer reduction' (HTR) effect. Under normal conditions, drag reducing additives can reduce convective heat transfer in even greater amounts than they do turbulent pressure losses. Much of the recent research in the field of surfactant drag reduction has, therefore, been dedicated to the mitigation of heat transfer reduction. In this work, two projects are presented which successfully achieve this goal. In the first, a constricted heat exchanger is used to locally increase the shear stresses experienced by the working fluid. Simultaneously, a `weak' drag reducing solution comprised of quaternary ammonium salts with saturated tails 16 and 14 carbons in length and the counterion 3-chlorobenzoic acid. In conjunction with the constricted heat exchanger, this mixture is able to simultaneously generate high (>60%) DR and low (>30%) HTR over a range of flow rates and temperatures. Other unique properties of the system are examined, including switchability and hysteresis. The second study involves the design and application of 'gentle' static mixers. Rather than being designed to destroy the micellar structure thought to be responsible for DR, these mixers are intended to periodically disrupt the thermal boundary layer in the heat exchanger, thus improving heat transfer. Two designs are examined: a finned mixer and a double-helical mixer, both capable of reducing HTR to 30% from a high of 90%. Design considerations were discussed, as well as future goals to further extend the work.

Download or read book Developments in Heat Transfer written by Marco Aurelio Dos Santos Bernardes and published by IntechOpen. This book was released on 2011-09-15 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises heat transfer fundamental concepts and modes (specifically conduction, convection and radiation), bioheat, entransy theory development, micro heat transfer, high temperature applications, turbulent shear flows, mass transfer, heat pipes, design optimization, medical therapies, fiber-optics, heat transfer in surfactant solutions, landmine detection, heat exchangers, radiant floor, packed bed thermal storage systems, inverse space marching method, heat transfer in short slot ducts, freezing an drying mechanisms, variable property effects in heat transfer, heat transfer in electronics and process industries, fission-track thermochronology, combustion, heat transfer in liquid metal flows, human comfort in underground mining, heat transfer on electrical discharge machining and mixing convection. The experimental and theoretical investigations, assessment and enhancement techniques illustrated here aspire to be useful for many researchers, scientists, engineers and graduate students.

Download or read book Evaluation of Alumina Nanofluids and Surfactant Drag Reducing Solutions to Improve Heat Transfer for Aircraft Cooling Systems written by Javier Artemio Narvaez Bazan and published by . This book was released on 2018 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a critical need for improved coolants for military aircraft applications. Research in this area has focused on either synthesizing novel coolants with improved thermal properties or developing additives for current coolants that can improve heat transfer capability in recirculating systems. This dissertation focuses on the latter alternative investigating the effect of nanoparticles or drag-reducing surfactant additives on effective heat transfer coefficients. Nanoparticles are reported to not only enhance thermal conductivity of coolants, but also increase the heat transfer coefficient. Some setbacks related to the use of nanofluids have been identified, such as increased pressure loss, erosion, and fluid instability. Surfactant drag-reducing additives greatly reduce skin friction, thereby reducing resistance to flow in tubes. Lower flow resistance means that the volumetric flow rate can be greatly increased at constant pumping power. Under these circumstances, the heat transfer coefficient can be enhanced. However, researchers have found that the heat transfer coefficient in tube heat exchangers is reduced by the addition of drag-reducing additives. Moreover, the percentage of heat transfer reduction in tube heat exchangers is greater than the corresponding drag reduction. The reason for the loss of heat transfer is that surfactant drag reducers lower flow resistance by damping turbulent eddies, which are known to drive heat transfer. Several researchers have tried to overcome heat transfer reduction in heat exchangers by different means described in this dissertation. However, despite their efforts, the improvements they achieved were not enough to eliminate the heat transfer reduction. Instead of focusing on turbulence, this dissertation explored the impact of increased heat transfer area per volume within microchannel devices, as the flow regime is typically laminar. The objective of this dissertation is to evaluate two approaches for heat transfer enhancement by additives--nanoparticles and surfactants--in aircraft cooling systems. For proof-of-concept experiments carried out in this work, the base fluid selected was DI water. A computational fluid dynamics study on the pressure, velocity, and temperature profiles was performed to analyze the flow and temperature patterns inside a cold plate, the microcooling device used in this research. A small study on the flow inside an elbow was also performed to analyze secondary flows. Alumina/DI water nanofluids were evaluated at system level. It was observed that, at the same volumetric flow, there was no significant improvement in convective heat transfer coefficients. Problems such as increase of pressure loss, particle settling, and especially vaporization were observed. Next, an aqueous surfactant solution was also tested within the heat exchanger system. A small reduction in both pressure loss and heat transfer coefficient at the system level was found. The relatively high pressure loss was due to the large ratio of form friction to total friction. Other problems associated with the use of surfactants as a heat transfer enhancer were surfactant poisoning and chemical degradation. Finally, alternatives to improve heat transfer coefficient by nanoparticles and surfactant additives are proposed, based on the analysis identified by this study.

Download or read book Investigation of Relationships Among Microstructure Rheology Drag Reduction and Heat Transfer of Drag Reducing Surfactant Solutions written by Yunying Qi and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Drag reducing (DR) surfactant solutions can reduce pumping energy requirements in district heating and cooling (DHC) systems by 30-60%. To enhance the heat transfer ability of DR surfactant solutions, three methods were investigated. Fluted tube-in-tube heat exchangers and installing destructive devices at heat exchanger entrances were found to be very effective with moderate pressure drop penalties. The former is good for new DHC systems while the latter is ideal for existing DHC systems. Ultrasonic energy break up surfactant microstructures and enhance their heat transfer ability was effective for viscoelastic drag reducing surfactant solutions. The destructive devices and ultrasonic energy temporarily destroy the surfactant microstructure which enhances heat transfer. The microstructure recovers quickly and the solution regains its DR ability downstream of the exchanger. Unsaturated hydrocarbon chains with cis and trans configurations with different counterion/surfactant ratios influence the effective DR temperature range of cationic surfactant solutions, their shear degradation, their rheological behavior and their microstructures. Shearing effects on the microstructures of different DR surfactant solutions were studied using SANS. Surfactant microstructures aligned along the flow direction under shear. However, the critical shear rate for the initiation of alignment depends on surfactant microstructure. Differences and their relation to rheological properties and DR abilities are discussed. Shear induced structures (SIS) are accompanied by first normal stress difference (N1). Non-viscoelastic DR systems do not show SIS and N1. Threadlike micelle structures appear to be present in all DR surfactant solutions under shear, however. While some DR surfactant solutions have low extensional/shear viscosity ratios at extensional rates

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 Heat Transfer Performance with Surfactants as Additives written by Shareen Salwam and published by . This book was released on 2014 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technology of pipeline drag reduction has been advanced for many years. It has improved in increasing the pipeline flow potential in crude oil transportation. In the pipeline system, surfactant solutions that caused drag reduction are capable in lowering the pumping power. In this research experiment, photosensitive cinnamate group derivative compound and polymer surfactant as drag reducing agents were chosen mainly to study on the effect of photosensitive surfactant on the drag reduction and heat transfer performance and also the effect of ultraviolet light irradiation on the heat transfer and drag reduction ability of the surfactants. Water was used as the working fluid in this research and the main equipment used was Rotating Disk Apparatus. Combination of these compounds formed viscoelasticity solution. In this research experiment, rheological measurements, drag reduction and heat transfer reduction percentages were evaluated. In conclusion, these viscoelasticity solutions have a higher drag reduction percentages at higher rotational speed after ultraviolet irradiation. Lower heat transfer reduction percentages were analysed for pure photosensitive cinnamate group derivative after ultraviolet irradiation and polymer surfactant solutions hence, indicated that both solutions are good thermal conductor.

Download or read book Drag Reduction in Fluid Flows written by Robert H. J. Sellin and published by . This book was released on 1989 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Practical Aspects of Chemical Engineering written by Marek Ochowiak and published by Springer Nature. This book was released on 2020-05-08 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses chemical engineering and processing, presenting selected contributions from PAIC 2019. It covers interdisciplinary technologies and sciences, like drug-delivery systems, nanoscale technology, environmental control, modelling and computational methods. The book also explores interdisciplinary aspects of chemical and biochemical engineering interconnected with process system engineering, process safety and computer science.

Download or read book Hydraulic Drag and Heat Transfer Properties of Dilute Aqueous Surfactant Solutions Under Turbulent Flow Conditions written by Simon E. Day and published by . This book was released on 1991 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Developments in Heat Transfer written by Marco Aurelio Dos Santos Bernardes and published by BoD – Books on Demand. This book was released on 2011-09-15 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises heat transfer fundamental concepts and modes (specifically conduction, convection and radiation), bioheat, entransy theory development, micro heat transfer, high temperature applications, turbulent shear flows, mass transfer, heat pipes, design optimization, medical therapies, fiber-optics, heat transfer in surfactant solutions, landmine detection, heat exchangers, radiant floor, packed bed thermal storage systems, inverse space marching method, heat transfer in short slot ducts, freezing an drying mechanisms, variable property effects in heat transfer, heat transfer in electronics and process industries, fission-track thermochronology, combustion, heat transfer in liquid metal flows, human comfort in underground mining, heat transfer on electrical discharge machining and mixing convection. The experimental and theoretical investigations, assessment and enhancement techniques illustrated here aspire to be useful for many researchers, scientists, engineers and graduate students.

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 Practical Aspects of Chemical Engineering written by Marek Ochowiak and published by Springer. This book was released on 2021-05-09 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses chemical engineering and processing, presenting selected contributions from PAIC 2019. It covers interdisciplinary technologies and sciences, like drug-delivery systems, nanoscale technology, environmental control, modelling and computational methods. The book also explores interdisciplinary aspects of chemical and biochemical engineering interconnected with process system engineering, process safety and computer science.

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 Encyclopedia of Chemical Processing Online written by Sunggyu Lee and published by CRC Press. This book was released on 2005-11-01 with total page 3338 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition Encyclopedia supplies nearly 350 gold standard articles on the methods, practices, products, and standards influencing the chemical industries. It offers expertly written articles on technologies at the forefront of the field to maximize and enhance the research and production phases of current and emerging chemical manufacturing practices and techniques. This collecting of information is of vital interest to chemical, polymer, electrical, mechanical, and civil engineers, as well as chemists and chemical researchers. A complete reconceptualization of the classic reference series the Encyclopedia of Chemical Processing and Design, whose first volume published in 1976, this resource offers extensive A-Z treatment of the subject in five simultaneously published volumes, with comprehensive indexing of all five volumes in the back matter of each tome. It includes material on the design of key unit operations involved with chemical processes; the design, unit operation, and integration of reactors and separation systems; process system peripherals such as pumps, valves, and controllers; analytical techniques and equipment; and pilot plant design and scale-up criteria. This reference contains well-researched sections on automation, equipment, design and simulation, reliability and maintenance, separations technologies, and energy and environmental issues. Authoritative contributions cover chemical processing equipment, engineered systems, and laboratory apparatus currently utilized in the field. It also presents expert overviews on key engineering science topics in property predictions, measurements and analysis, novel materials and devices, and emerging chemical fields. ALSO AVAILABLE ONLINE This Taylor & Francis encyclopedia is also available through online subscription, offering a variety of extra benefits for both researchers, students, and librarians, including: Citation tracking and alerts Active reference linking Saved searches and marked lists HTML and PDF format options Contact Taylor and Francis for more information or to inquire about subscription options and print/online combination packages. US: (Tel) 1.888.318.2367; (E-mail) [email protected] International: (Tel) +44 (0) 20 7017 6062; (E-mail) [email protected]