[PDF] Theoretical And Numerical Investigation Of Thermodiffusion Soret Effect And Thermosolutal Convection eBook

Author : Shu Pan
Publisher :
Page : 232 pages
File Size : 19,91 MB
Release : 2007
Category :
ISBN : 9780494393888

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Thermodiffusion is a mass diffusion phenomenon induced by a temperature gradient and has attracted increasing interests from theorists and experimentalists. In this work, the modelling of thermodiffusion in fluids is theoretically treated in the framework of non-equilibrium thermodynamics. The method developed in this work for thermodiffusion calculation have been incorporated into a computational fluid dynamics program to study the influence of the thermosolutal convection caused by residual gravity and g-jitter. The results have shown that the influence of microgravity environment would become stronger with an increase in the acceleration level, while at the same acceleration level, the effect would decrease at higher frequencies. For an isopropanol-water mixture under a typical microgravity condition for thermodiffusion measurement, the effect of residual gravity lower than 10--5G or the g-jitter components with an acceleration level of 10--4 G and frequencies higher than 0.0005 Hz may be negligible. The analysis in this work has indicated that under the expected microgravity environment on the International Space Station, the influence of g-jitter on the thermodiffusion measurement may be negligibly small for frequencies lower than 1 Hz. Based on four postulates in non-equilibrium thermodynamics, a non-equilibrium thermodynamic approach has been developed for thermodiffusion in associating fluid mixtures. Using the thermodynamic properties provided by the PC-SAFT Equation of State, this approach was used to evaluate the thermal diffusion factor alphaT in aqueous alkanol solutions, including methanol-water, ethanol-water and isopropanol-water mixtures. Using two adjustable parameters calculated from experimental data, the approach has shown a successful estimation of the sign change in the thermodiffusion factor for these mixtures, which was an unresolved problem in thermodiffusion research. In addition to the new model for thermodiffusion in associating mixtures, the current approaches for thermal diffusion estimation in multicomponent hydrocarbon mixtures have been evaluated by comparisons with recent experimental data. Three equations of state, including Peng-Robinson, volume translated Peng-Robinson and PC-SAFT were used in the calculation. The Firoozabadi model combined with vtPR or PC-SAFT was shown to be applicable to thermal diffusion estimation for hydrocarbon mixtures, while PC-SAFT combined with the Firoozabadi model would be a promising choice for mixtures other than hydrocarbons due to the wide applicability of PC-SAFT.

Author : Donald A. Nield
Publisher : Springer
Page : 988 pages
File Size : 10,85 MB
Release : 2017-03-15
Category : Technology & Engineering
ISBN : 3319495623

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This updated edition of a widely admired text provides a user-friendly introduction to the field that requires only routine mathematics. The book starts with the elements of fluid mechanics and heat transfer, and covers a wide range of applications from fibrous insulation and catalytic reactors to geological strata, nuclear waste disposal, geothermal reservoirs, and the storage of heat-generating materials. As the standard reference in the field, this book will be essential to researchers and practicing engineers, while remaining an accessible introduction for graduate students and others entering the field. The new edition features 2700 new references covering a number of rapidly expanding fields, including the heat transfer properties of nanofluids and applications involving local thermal non-equilibrium and microfluidic effects.

Author : D.A. Nield
Publisher : Springer Science & Business Media
Page : 672 pages
File Size : 40,73 MB
Release : 2006-02-23
Category : Science
ISBN : 9780387290966

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Nonprofit organizations are suffering from the continuing economic downturn. Donations are decreasing while demand for services is growing, forcing these organizations to be increasingly efficient and effective with their funds. This book introduces the reader to the basic concepts of project management. It provides approaches and templates to help nonprofit managers quickly implement practices to help them manage their limited resources, both financial and volunteer. The book also provides a tool to help the project team determine which practices are most appropriate. The book explores how social media and other technology tools can be used to assist in the management of time-sensitive projects and shows how project portfolio management can be a tool to assist in communications with boards of directors and other governing entities. The project portfolio is a tool that development office managers can easily implement and adopt to facilitate resource assignment. Finally, the book offers three case studies of nonprofit projects that went awry and shows how project management would have assisted.

Author : Nazibuddin Ahmed
Publisher : Springer Nature
Page : 211 pages
File Size : 46,41 MB
Release : 2023-01-06
Category : Science
ISBN : 9811971536

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This book presents a theoretical analysis of several problems in thermal and solutal convections in magneto-hydrodynamic (MHD) flows. It provides a systemic discussion on the development of fluid dynamics, continuum hypothesis, Newton’s law of viscosity, heat transfer, mass transfer, thermal diffusion, diffusion-thermo-MHD, gray and non-gray gases, Fourier’s law of conduction, and Fick’s law of diffusion in such a way that readers with little knowledge in physics will find it easier to understand the contents. Some physical principles, such as those governing fluid motion, fluid temperature, and fluid concentration, are presented in vector form, allowing the corresponding form to be derived in any orthogonal curvilinear coordinate system. Laplace transform technique in closed form is used to obtain exact solutions to unsteady one-dimensional flow problems, an implicit finite difference method of Crank–Nicholson type is used to solve unsteady two-dimensional flow problems, and an asymptotic series expansion method is used to solve the governing equations of the steady three-dimensional flow problem analytically. Flow and transport phenomena are thoroughly treated in each chapter separately. This book emphasizes the influence of an induced magnetic field. The outcomes of the works are graphically depicted so that readers can gain a tangible understanding of the problems. It also includes a list of inverse Laplace transforms (ILTs) for several specific functions, some of which are not found in the existing literature. The ILTs of special functions are given in brief form and can further be utilized as standard formulae in finding those as special cases. Some new special functions are introduced in the book, along with appropriate definitions. As a result, the formulations for velocity, temperature, concentration, skin friction, Nusselt number, and Sherwood number have been appeared in brief and convenient forms that are uncommon in other literature. This book addresses numerous areas of contemporary magneto-fluid dynamics research that have major implications in engineering. It is primarily intended for researchers working in the field of heat and mass transfer in hydromagnetic flows.

Author : Sadik Dost
Publisher : Elsevier
Page : 505 pages
File Size : 39,36 MB
Release : 2006-11-17
Category : Science
ISBN : 0080467946

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Single Crystal Growth of Semiconductors from Metallic Solutions covers the four principal growth techniques currently in use for the growth of semiconductor single crystals from metallic solutions. Providing an in-depth review of the state-of-the-art of each, both experimentally and by numerical simulations. The importance of a close interaction between the numerical and experimental aspects of the processes is also emphasized. Advances in the fields of electronics and opto-electronics are hampered by the limited number of substrate materials which can be readily produced by melt-growth techniques such as the Czochralski and Bridgman methods. This can be alleviated by the use of alternative growth techniques, and in particular, growth from metallic solutions. The principal techniques currently in use are: Liquid Phase Epitaxy; Liquid Phase Electroepitaxy; the Travelling Heater Method, and; Liquid Phase Diffusion. Single Crystal Growth of Semiconductors from Metallic Solutions will serve as a valuable reference tool for researchers, and graduate and senior undergraduate students in the field of crystal growth. It covers most of the models developed in recent years. The detailed development of basic and constitutive equations and the associated interface and boundary conditions given for each technique will be very valuable to researchers for the development of their new models. * Describes the fundamentals of crystal growth modelling* Providing a state-of-the art description of the mathematical and experimental growth processes * Allows reader to gain clear insight into the practical and mathematical aspects of the topic