Particle Dispersion and Inter-phase Kinetic Energy Transfer in a Turbulent, Two-phase Shear Layer

Particle Dispersion and Inter-phase Kinetic Energy Transfer in a Turbulent, Two-phase Shear Layer

Author: Kenneth T. Kiger

Publisher:

Published: 1995

Total Pages: 368

ISBN-13:

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The transport of heavy, polydispersed particles and the inter-phase transfer of kinetic energy is measured experimentally in a turbulent shear layer. Specifically, fundamental/subharmonic forcing and conditional-averaging techniques were used to study the particle/turbulence interaction with the large-scale, spanwise, coherent vortices, starting from their initial roll-up through the first pairing event. It is shown that the pairing event plays a homogenizing role on the particulate field, but the amount of homogenization is strongly dependent upon the particle's viscous relaxation time, the eddy turnover time, as well as the time the particles are allowed to interact with each scale prior to a pairing event. Thus, even though the smaller size particles become well-mixed across the structure, the larger sizes are still dispersed in an inhomogeneous fashion. The dispersed/carrier phase coupling was examined through the measurement of conditionally-averaged kinetic energy transfer (which results from the work done to accelerate or decelerate the dispersed phase), as well as the conditionally-averaged particle dissipation (energy dissipated by shear deformation in the carrier phase due to the relative slip between the particles and the carrier fluid).


Turbulent Multiphase Flows with Heat and Mass Transfer

Turbulent Multiphase Flows with Heat and Mass Transfer

Author: Roland Borghi

Publisher: John Wiley & Sons

Published: 2013-12-11

Total Pages: 462

ISBN-13: 1118790197

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Numerous industrial systems or natural environments involve multiphase flows with heat and mass transfer. The authors of this book present the physical modeling of these flows, in a unified way, which can include various physical aspects and several levels of complexity. Thermal engineering and nuclear reactors; the extraction and transport of petroleum products; diesel and rocket engines; chemical engineering reactors and fluidized beds; smoke or aerosol dispersion; landslides and avalanches − the modeling of multiphase flows with heat and mass transfer for all these situations can be developed following a common methodology. This book is devoted to the description of the mathematical bases of how to incorporate adequate physical ingredients in agreement with known experimental facts and how to make the model evolve according to the required complexity. Contents Part 1. Approach and General Equations 1. Towards a Unified Description of Multiphase Flows. 2. Instant Equations for a Piecewise Continuous Medium. 3. Description of a “Mean Multiphase Medium”. 4. Equations for the Mean Continuous Medium. Part 2. Modeling: A Single Approach Adaptable to Multiple Applications 5. The Modeling of Interphase Exchanges. 6. Modeling Turbulent Dispersion Fluxes. 7. Modeling the Mean Gas–Liquid Interface Area per Unit Volume. 8. “Large Eddy Simulation” Style Models. 9. Contribution of Thermodynamics of Irreversible Processes. 10. Experimental Methods. 11. Some Experimental Results Pertaining to Multiphase Flow Properties that Are Still Little Understood. Part 3. From Fluidized Beds to Granular Media 12. Fluidized Beds. 13. Generalizations for Granular Media. 14. Modeling of Cauchy Tensor of Sliding Contacts. 15. Modeling the Kinetic Cauchy Stress Tensor. Part 4. Studying Fluctuations and Probability Densities 16. Fluctuations of the Gas Phase in Reactive Two-Phase Media. 17. Temperature Fluctuations in Condensed Phases. 18. Study of the PDF for Velocity Fluctuations and Sizes of Parcels. About the Authors Roland Borghi is Professor Emeritus at Ecole Centrale Marseille in France and works as a consultant in the space, petrol and automobile sectors. His research activities cover fluid mechanics, combustion and flames, and multi-phase and granular flows. He was a member of the CNRS scientific committee and a laureate of the French Academy of Science. Fabien Anselmet is Professor at Ecole Centrale Marseille in France. His research activities focus on the turbulence of fluids and its varied applications in industry and in fields linked to the environment. With a unified, didactic style, this text presents tangible models of multiphase flows with heat and mass transfer with attention to various levels of complexities. It addresses thermal engineering and nuclear reactors, extraction and transport of petroleum products, diesel engines and rocket engines, chemical engineering reactors and fluidized beds, smoke or aerosol dispersion, and landslides and avalanches. Engineers, researchers, and scientists will appreciate the discussions of modeling principles, flows and granular media, and fluctuations around averages.


Modeling Approaches and Computational Methods for Particle-laden Turbulent Flows

Modeling Approaches and Computational Methods for Particle-laden Turbulent Flows

Author: Shankar Subramaniam

Publisher: Academic Press

Published: 2022-10-20

Total Pages: 588

ISBN-13: 0323901344

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Modelling Approaches and Computational Methods for Particle-laden Turbulent Flows introduces the principal phenomena observed in applications where turbulence in particle-laden flow is encountered while also analyzing the main methods for analyzing numerically. The book takes a practical approach, providing advice on how to select and apply the correct model or tool by drawing on the latest research. Sections provide scales of particle-laden turbulence and the principal analytical frameworks and computational approaches used to simulate particles in turbulent flow. Each chapter opens with a section on fundamental concepts and theory before describing the applications of the modelling approach or numerical method. Featuring explanations of key concepts, definitions, and fundamental physics and equations, as well as recent research advances and detailed simulation methods, this book is the ideal starting point for students new to this subject, as well as an essential reference for experienced researchers. - Provides a comprehensive introduction to the phenomena of particle laden turbulent flow - Explains a wide range of numerical methods, including Eulerian-Eulerian, Eulerian-Lagrange, and volume-filtered computation - Describes a wide range of innovative applications of these models


Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes

Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes

Author: P.A. Davies

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 513

ISBN-13: 9401109184

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Challenging problems involvrllg jet and plume phenomena are common to many areas of fundamental and applied scientific research, and an understanding of plume and jet behaviour is essential in many geophysical and industrial contexts. For example, in the field of meteorology, where pollutant dispersal takes place by means of atmospheric jets and plumes formed either naturally under conditions of convectively-driven flow in the atmospheric boundary layer, or anthropogenically by the release of pollutants from tall chimneys. In other fields of geophysics, buoyant plumes and jets are known to play important roles in oceanic mixing processes, both at the relatively large scale (as in deep water formation by convective sinking) and at the relatively small scale (as with plume formation beneath ice leads, for example). In the industrial context, the performances of many engineering systems are determined primarily by the behaviour of buoyant plumes and jets. For example, (i) in sea outfalls, where either sewage or thermal effluents are discharged into marine and/or freshwater environments, (ii) in solar ponds, where buoyant jets are released under density interfaces, (iii) in buildings, where thermally-generated plumes affect the air quality and ventilation properties of architectural environments, (iv) in rotating machinery where fluid jet~ are used for cooling purposes, and (v) in long road and rail tunnels, where safety and ventilation prcedures rely upon an understanding of the behaviour of buoyant jets. In many other engineering and oceanographic contexts, the properties of jets and plumes are of great importance.


Droplets and Sprays

Droplets and Sprays

Author: Saptarshi Basu

Publisher: Springer

Published: 2017-12-11

Total Pages: 433

ISBN-13: 9811074496

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This book focuses on droplets and sprays relevant to combustion and propulsion applications. The book includes fundamental studies on the heating, evaporation and combustion of individual droplets and basic mechanisms of spray formation. The contents also extend to the latest analytical, numerical and experimental techniques for investigating the behavior of sprays in devices like combustion engines and gas turbines. In addition, the book explores several emerging areas like interactions between sprays and flames and the dynamic characteristics of spray combustion systems on the fundamental side, as well as the development of novel fuel injectors for specific devices on the application side. Given its breadth of coverage, the book will benefit researchers and professionals alike.