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Author: Pouria Baghaei Publisher: ISBN: Category : Languages : en Pages : 135
Book Description
The effect of additives on friction loss in upward turbulent flow was investigated in this experimental study. Additives such as air bubbles, frother and polymer were added to water flow to study their influence on the friction factor. In order to perform this research an experimental set-up was designed and developed. The test sections of the set-up consisted of three vertical pipes of different diameters. The set-up was equipped with three pressure transducers, a magnetic flowmeter, gas spargers and a gas rotameter. The first phase of the experimental program involved calibration of the various devices and pipelines test-sections. The single-phase pressure loss data obtained from the pipelines exhibited good agreement with the standard equations. The second phase of the experimental program dealt with the effect of air bubbles and additives (frother and polymer) on drag reduction in turbulent flows. The experimental results showed that bubbles in the range of 1 mm-3 mm increased the wall shear stress. Therefore, no drag-reduction effect was observed. On the contrary, a significant increase in friction factor was observed at low Reynolds numbers as a result of larger bubble sizes and lower turbulence intensities. The friction factor at low Reynolds numbers could be decreased by decreasing the bubble size by addition of frother to the flow system. The combination of polymer and air bubbles showed a drag reduction of up to 60%. It is also evident from the experiment results that the addition of polymer to bubbly flow system leads to fully homogeneous mixture.
Author: Pouria Baghaei Publisher: ISBN: Category : Languages : en Pages : 135
Book Description
The effect of additives on friction loss in upward turbulent flow was investigated in this experimental study. Additives such as air bubbles, frother and polymer were added to water flow to study their influence on the friction factor. In order to perform this research an experimental set-up was designed and developed. The test sections of the set-up consisted of three vertical pipes of different diameters. The set-up was equipped with three pressure transducers, a magnetic flowmeter, gas spargers and a gas rotameter. The first phase of the experimental program involved calibration of the various devices and pipelines test-sections. The single-phase pressure loss data obtained from the pipelines exhibited good agreement with the standard equations. The second phase of the experimental program dealt with the effect of air bubbles and additives (frother and polymer) on drag reduction in turbulent flows. The experimental results showed that bubbles in the range of 1 mm-3 mm increased the wall shear stress. Therefore, no drag-reduction effect was observed. On the contrary, a significant increase in friction factor was observed at low Reynolds numbers as a result of larger bubble sizes and lower turbulence intensities. The friction factor at low Reynolds numbers could be decreased by decreasing the bubble size by addition of frother to the flow system. The combination of polymer and air bubbles showed a drag reduction of up to 60%. It is also evident from the experiment results that the addition of polymer to bubbly flow system leads to fully homogeneous mixture.
Author: Pouria Baghaei Publisher: LAP Lambert Academic Publishing ISBN: 9783659219443 Category : Languages : en Pages : 152
Book Description
Drag reduction is a remarkable ability to reduce the frictional resistance in the turbulent flow by adding a low concentration of certain additives, drag reducing additive agents (DRA). High costs of fluid transportation (such as pumping the liquids into the pipelines) in production processes has made drag reduction subject of lots of research in the past decades. Several studies have been carried out on reducing the friction factor in flow system using different drag reducing agents. However, there are a few investigations carried out on the effects of combining two or more DRAs. The purpose of this study is to investigate the effects of different additives on drag reduction using various methods. Effects of Polymer, Air bubbles, Aerofroth, and their combination have been investigated through the experimental study.
Author: Feng-Chen Li Publisher: John Wiley & Sons ISBN: 1118181115 Category : Science Languages : en Pages : 233
Book Description
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.
Author: A. Gyr Publisher: Springer Science & Business Media ISBN: 9401712956 Category : Technology & Engineering Languages : en Pages : 243
Book Description
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.
Author: Keizo Watanabe Publisher: Academic Press ISBN: 0128099429 Category : Technology & Engineering Languages : en Pages : 224
Book Description
Drag Reduction of Complex Mixtures discusses the concept of drag reduction phenomena in complex mixtures in internal and external flows that are shown experimentally by dividing flow patterns into three categories. The book is intended to support further experiments or analysis in drag reduction. As accurately modeling flow behavior with drag reduction is always complex, and since drag reducing additives or solid particles are mixed in fluids, this book covers these complex phenomena in a concise, but comprehensive manner. Comprehensively addresses a range of drag reduction themes involving different kinds of complex mixtures Provides data to support further experimentation and computer modeling of drag in complex flow Includes an introduction to the nature and characteristics of different kinds of complex mixtures
Author: Marc Perlin Publisher: World Scientific ISBN: 9814612278 Category : Technology & Engineering Languages : en Pages : 165
Book Description
This text presents the state of the art in friction drag/resistance reduction technologies for BODIES and crafts operating in liquids at and beneath the free surface. It is useful for professionals with backgrounds in advanced fluid dynamics as well as by academics teaching introductory graduate courses in this area. Active control of resistance will include a discussion of friction reduction, for example through the injection of gas that can form air layers and polymers that initially reside adjacent to the hull, including the use of partial and super cavities. The book discusses passive resistance control achieved through changes in the overall hull shape and appendages, including the application of lifting bodies, bulbous bows, and stern flaps. It also addresses passive reduction of skin friction through the application of hull coatings and other elements of hull husbandry.
Author: Pouria Baghaei
Author: Pouria Baghaei
Author: Pouria Baghaei
Author: Feng-Chen Li
Author: A. Gyr
Author: Keizo Watanabe
Author: 
Author: C. Sinclair Wells
Author: Marc Perlin
Author: A. White
Author: United States. National Bureau of Standards