Turbulent Drag Reduction by Surfactant Additives E-Book

Feng-Chen Li

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 407

Veröffentlichungsjahr: 2011

Beschreibung

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.

Leseprobe

Contents

Cover

Title Page

Copyright

Preface

Chapter 1: Introduction

1.1 Background

1.2 Surfactant Solution

1.3 Mechanism and Theory of Drag Reduction by Surfactant Additives

1.4 Application Techniques of Drag Reduction by Surfactant Additives

References

Chapter 2: Drag Reduction and Heat Transfer Reduction Characteristics of Drag-Reducing Surfactant Solution Flow

2.1 Fundamental Concepts of Turbulent Drag Reduction

2.2 Characteristics of Drag Reduction by Surfactant Additives and Its Influencing Factors

2.3 The Diameter Effect of Surfactant Drag-reducing Flow and Scale-up Methods

2.4 Heat Transfer Characteristics of Drag-reducing Surfactant Solution Flow and Its Enhancement Methods

References

Chapter 3: Turbulence Structures in Drag-Reducing Surfactant Solution Flow

3.1 Measurement Techniques for Turbulence Structures in Drag-Reducing Flow

3.2 Statistical Characteristics of Velocity and Temperature Fields in Drag-reducing Flow

3.3 Characteristics of Turbulent Vortex Structures in Drag-reducing Flow

3.4 Reynolds Shear Stress and Wall-Normal Turbulent Heat Flux

References

Chapter 4: Numerical Simulation of Surfactant Drag Reduction

4.1 Direct Numerical Simulation of Drag-reducing Flow

4.2 RANS of Drag-reducing Flow

4.3 Governing Equation and DNS Method of Drag-reducing Flow

4.4 DNS Results and Discussion for Drag-reducing Flow and Heat Transfer

4.5 Conclusion and Future Work

References

Chapter 5: Microstructures and Rheological Properties of Surfactant Solution

5.1 Microstructures in Surfactant Solution and Its Visualization Methods

5.2 Rheology and Measurement Methods of Surfactant Solution

5.3 Factors Affecting the Rheological Characteristics of Surfactant Solution

5.4 Characterization of Viscoelasticity of Drag-reducing Surfactant Solution by Using Free Surface Swirling Flow

5.5 Molecular and Brownian Dynamics Simulations of Surfactant Solution

References

Chapter 6: Application Techniques for Drag Reduction by Surfactant Additives

6.1 Problems That Need to Be Solved in Engineering Applications

6.2 Separation Techniques for Surfactant Solution [4]

6.3 Drag Reduction Stability of Surfactant Solutions [4]

6.4 Applications of Surfactant Drag Reduction

References

Index

This edition first published 2012 © 2012 Higher Education Press. All rights reserved.

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Library of Congress Cataloging-in-Publication Data

Turbulent drag reduction by surfactant additives / Feng-Chen Li... [et al.].

p. cm.

Includes bibliographical references and index.

ISBN 978-1-118-18107-2 (cloth)

1.   Drag (Aerodynamics)   2. Turbulence.   3.   Frictional resistance (Hydrodynamics)   4.   Surface active agents.   I. Li, Feng-Chen, 1971-

TL574.D7T87 2011

629.132′34–dc23

2011034428

Print ISBN: 9781118181072

Preface

The subject of this book is the presentation of detailed information on turbulence characteristics, theories, special techniques, and application issues for drag-reducing flows by surfactant additives, mainly based on state-of-the-art research results by the authors through experimental studies, numerical simulations, and theoretical analyses.

The phenomenon of turbulent drag reduction by additives has attracted the interest of researchers in the fields of chemical engineering, turbulence, fluid dynamics, rheology, petroleum, municipal and environmental engineering, and so on, for more than half a century. Turbulent drag reducing flows are especially complex due to the twofold effects of the turbulence itself and the drag reduction phenomenon induced by viscoelacticity. This complexity, combined with the great potential for drag reduction in industrial applications, has driven researchers to continuously approach the problem in an interdisciplinary fashion. Researchers are working to clarify the mechanism of drag reduction by additives, developing particular research approaches for this unique phenomenon, and exploring the characteristics of drag-reduced turbulent flows. Throughout this process, they have established increasingly exhaustive theoretical descriptions for the rheological properties of the fluid and drag reduction phenomenon of the flow, promoting the applications of this phenomenon in practical systems. This book provides important information on turbulent drag reduction by surfactant additives, particularly information covering introductions to experimental studies using laser techniques (laser Doppler velocimetry and particle image velocimetry), direct numerical simulations with special treatment of constitutive equations for viscoelastic fluid and numerical simulation algorithms, Brownian dynamic simulations of the rheological properties of surfactant solution with consideration of microstructures in the fluid, field tests and other issues associated with practical applications, and elucidations and summarizations of state-of-the-art results obtained from those studies. The contents of this book are the central concerns of the interdisciplinary community related to turbulent drag reduction by additives.

The authors do not claim that they have addressed in this book all the relevant issues of turbulent drag reduction by additives. Particularly unbounded flows with drag-reducing effects, drag-reducing polymer solution flows, the chemistry of drag-reducing additives, and so on were not mentioned or elaborated in detail in this book.

F.-C. Li composed Sections 1.1–1.3, 2.1, 2.2, 2.4, Chapter 3, Section 6.1 and the index. He also coordinated all procedures involved in the publication of this book. He would like to acknowledge the support from National Natural Science Foundation of China (NSFC; Grant No. 10872060 and 51076036) and Fundamental Research Funds for the Central Universities (Grant No. HIT. BRET1.2010008). For Chapter 4, he acknowledges the support from NSFC (Grant No. 50506017, 50876114 and 51134006). J.-J. Wei composed Sections 1.4, 2.3, Chapter 5 and Sections 6.2–6.4. He acknowledges the support from NSFC (Grant No. 51076124 and 50821064). Y. Kawaguchi contributed to modifying the organizations of the book and correcting the contents; he is also one of the key contributors of most of the studies involved in this book.

F.-C. LiB. YuJ.-J. WeiY. Kawaguchi

Chapter 1

Introduction

The problems associated with energy sources comprise one of the most important issues accompanying the development of economy all over the world. Energy saving itself has been treated as “the fifth biggest energy source,” following coal, petroleum, natural gas, and electricity, by scientists in China [1]. Much more importantly, the utilization of energy saving, that is, “this fifth energy source,” does not generate any emission of harmful gases such as CO2, NOx, and so on, but the reduction of equivalent amounts of emitted harmful gases can be obtained when gaining the energy source of “energy saving.” In developing countries such as China, both the energy consumption for productions and the energy consumption for economic output are much higher than in developed countries. Therefore, the potential of energy saving is huge if energy-saving approaches can be executed in many aspects. Turbulent drag reduction (DR) by additives is one such energy-saving approach used in the long-distance transportation of liquid or in the circulation systems of liquid. It has bright application prospectives.

1.1 Background

The turbulent DR technique is of great significance for improving energy utilization efficiency, protecting the ecological environment, and so on. In recent years, the international and academic community has been attaching more and more importance to fundamental and applicable studies on turbulent DR. Every year, specific academic conferences associated with turbulent DR are held or symposiums are opened for topics related to turbulent DR in the international conferences (or congresses) on fluid dynamics or fluid engineering. Turbulent DR has been a hot research topic in the field of fluid mechanics and fluid engineering. As an important branch of the field of turbulent DR, “turbulent DR by additives” herein refers to the liquid transportation technique that adding a minute amount (generally at a level of parts per million, or ppm) of additives may reduce the frictional drag greatly. Compared with other turbulent DR techniques, the salient features of this approach are its most obvious turbulent drag-reducing effect, its price (the lowest), and ease of operation.

As early as 1931, Forrest and Grierson [2] found that flow resistance could be reduced at the same flow rate when pulp fibers floated in the water turbulent flow in a pipe. But this phenomenon did not receive enough attention. The first one who observed the turbulent DR phenomenon by polymer additives was the American scholar Mysels [3, 4]. Mysels and his assistants found that after dissolving aluminum disoap into the gasoline flow in a pipe, the flow drag could be decreased at the same flow rate. However, due to the Second World War, this discovery wasn't published until 1949. In the first International Rheological Congress held in 1948 (its proceedings were published in 1949), the English scholar Toms reported the turbulent DR phenomenon of dilute polymer solution flow [5]. Hence, the turbulent DR phenomenon is often named the Toms effect. Since then, a large amount of investigations have been carried out all over the world on the mechanisms of turbulent DR and the real applications of the turbulent DR technique. The turbulent DR phenomenon has been well recognized, and significant progress for this technique has been made in real applications.

A typical example of a commercial application of the Toms effect was reported in 1982. Polymer additives were utilized to obtain the effects of reducing drag and increasing flow transportation efficiency in US Alaskan petroleum pipelines [6]. A relatively dense polymer solution was injected into the petroleum transportation piping system at four different pumping stations, which increased 25% of the flow rate of petroleum. For the Alaskan petroleum transportation piping system with an inner diameter of 48 in, the transportation capacity has been enlarged by 100 000 barrels. Presently, the turbulent drag-reducing effect of polymer additives has been widely used for long-distance petroleum transportation systems in order to increase their transportation capacity. However, exerted with some factors such as strong shear stress and high temperature, the flexible long-chain structure of polymer molecules, which plays the main role in the turbulent drag-reducing effect, can be destroyed. The destroyed structures cannot self-repair, resulting in the permanent loss of their drag-reducing effect. Therefore, polymer drag reducer is usually inapplicable for a liquid circulation system with a pump.