Preface1 Introduction1.1 Background1.2 Surfactant Solution1.2.1 Anionic Surfactant1.2.2 Cationic Surfactant1.2.3 Nonionic Surfactant1.2.4 Amphoteric Surfactant1.2.5 Zwitterionic Surfactant1.3 Mechanism and Theory of Drag Reduction by SurfactantAdditives1.3.1 Explanations of the Turbulent DR Mechanism from the Viewpointof Microstructures1.3.2 Explanations of the Turbulent DR Mechanism from the Viewpointof the Physics of Turbulence1.4 Application Techniques of Drag Reduction by SurfactantAdditives1.4.1 Heat Transfer Reduction of Surfactant Drag-reducingFlow1.4.2 Diameter Effect of Surfactant Drag-reducing Flow1.4.3 Toxic Effect of Cationic Surfactant Solution1.4.4 Chemical Stability of Surfactant Solution1.4.5 Corrosion of Surfactant SolutionReferences2 Drag Reduction and Heat Transfer Reduction Characteristics ofDrag-Reducing Surfactant Solution Flow2.1 Fundamental Concepts of Turbulent Drag Reduction2.2 Characteristics of Drag Reduction by Surfactant Additives andIts Influencing Factors2.2.1 Characteristics of Drag Reduction by SurfactantAdditives2.2.2 Influencing Factors of Drag Reduction by SurfactantAdditives2.3 The Diameter Effect of Surfactant Drag-reducing Flow andScale-up Methods2.3.1 The Diameter Effect and Its Influence2.3.2 Scale-up Methods2.3.3 Evaluation of Different Scale-up Methods2.4 Heat Transfer Characteristics of Drag-reducing SurfactantSolution Flow and Its Enhancement Methods2.4.1 Convective Heat Transfer Characteristics of Drag-reducingSurfactant Solution Flow2.4.2 Heat Transfer Enhancement Methods for Drag-reducingSurfactant Solution FlowsReferences3 Turbulence Structures in Drag-Reducing Surfactant SolutionFlow3.1 Measurement Techniques for Turbulence Structures inDrag-Reducing Flow3.1.1 Laser Doppler Velocimetry3.1.2 PIV3.2 Statistical Characteristics of Velocity and Temperature Fieldsin Drag-reducing Flow3.2.1 Distribution of Averaged Quantities3.2.2 Distribution of Fluctuation Intensities3.2.3 Correlation Analyses of Fluctuating Quantities3.2.4 Spectrum Analyses of Fluctuating Quantities3.3 Characteristics of Turbulent Vortex Structures in Drag-reducingFlow3.3.1 Identification Method of Turbulent Vortex by SwirlingStrength3.3.2 Distribution Characteristics of Turbulent Vortex in the x-yPlane3.3.3 Distribution Characteristics of Turbulent Vortex in the y-zPlane3.3.4 Distribution Characteristics of Turbulent Vortex in the x-zPlane3.4 Reynolds Shear Stress and Wall-Normal Turbulent Heat FluxReferences4 Numerical Simulation of Surfactant Drag Reduction4.1 Direct Numerical Simulation of Drag-reducing Flow4.1.1 A Mathematical Model of Drag-reducing Flow4.1.2 The DNS Method of Drag-reducing Flow4.2 RANS of Drag-reducing Flow4.3 Governing Equation and DNS Method of Drag-reducing Flow4.3.1 Governing Equation4.3.2 Numerical Method4.4 DNS Results and Discussion for Drag-reducing Flow and HeatTransfer4.4.1 The Overall Study on Surfactant Drag Reduction and HeatTransfer by DNS4.4.2 The Rheological Parameter Effect of DNS on Surfactant DragReduction4.4.3 DNS with the Bilayer Model of Flows with Newtonian andNon-Newtonian Fluid Coexistence4.5 Conclusion and Future WorkReferences5 Microstructures and Rheological Properties of SurfactantSolution6 Application Techniques for Drag Reduction by SurfactantAdditivesIndex
版權頁︰ 插圖︰ 184.108.40.206 Decoupling of Turbulent Fluctuations It has been indicated from many studies that the effect of drag reducer on turbulent flows also appears as the decreased correlation between the axial and radial fluctua-tions. This effect is named "decoupling." The decoupling of turbulent fluctuations can decrease the Reynolds stress. According to the quantitative relationship between Reynolds shear stress and the turbulent contribution to frictional drag coefficient deduced by Fukagata et al. （i.e., the FIK equation） （38）, a decrease of Reynolds shear stress directly results in a decrease of the friction factor of turbulent flow, and so turbulent DR. Actually, a decrease of Reynolds stress is caused by twofold effects, that is, the decoupling of turbulent fluctuations and turbulence suppression （17,33,39-41 ）.This postulation is also correct qualitatively. 220.127.116.11 Viscoelasticity All polymer and surfactant solutions with turbulent drag-reducing effects display viscoelastic rheological properties. With the development of viscoelastic fluid mechanics, some researchers proposed that the drag-reducing effect of polymer and surfactant solutions is the result of the interaction between viscoelasticity and turbulent vortices. The microstructures （polymer molecule chains or network structures in surfactant solution） in the drag reducer solution at a high-shear-rate region can absorb the turbulent kinetic energy of small vortices within the energy-containing range and store it. When the microstructures are diffused or convected to a low-shear-rate region,they will be relaxed to a random threadlike entanglement and the stored energy will be released to the low-wave-number vortices （large-scaled vortices） in the form of elastic stress waves, which greatly decreases the dissipation of turbulent kinetic energy and induces turbulent DR. The viscoelastic theory for the mechanism of turbulent DR by additives was proposed by DeGennes （42）. The viscoelasticity postulation not only explains the turbulent DR phenomenon in many polymer and surfactant solution flows with viscoelasticity, but also estimates the DR rate quantitatively. It is also a powerful tool for studying the mechanism of turbulent DR from the viewpoint of the physics of turbulence and developing new quantitative analysis theories for turbulent drag-reducing flows. However, this postulation was challenged by the "anisotropic stresses"hypothesis proposed by Toonder （43）.
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