Macroscopic Description Of Rarefied Gas Flows In The Transition Regime
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Macroscopic Transport Equations For Rarefied Gas Flows
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Author : Henning Struchtrup
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-06-15
Macroscopic Transport Equations For Rarefied Gas Flows written by Henning Struchtrup and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-06-15 with Science categories.
The well known transport laws of Navier-Stokes and Fourier fail for the simulation of processes on lengthscales in the order of the mean free path of a particle that is when the Knudsen number is not small enough. Thus, the proper simulation of flows in rarefied gases requires a more detailed description. This book discusses classical and modern methods to derive macroscopic transport equations for rarefied gases from the Boltzmann equation, for small and moderate Knudsen numbers, i.e. at and above the Navier-Stokes-Fourier level. The main methods discussed are the classical Chapman-Enskog and Grad approaches, as well as the new order of magnitude method, which avoids the short-comings of the classical methods, but retains their benefits. The relations between the various methods are carefully examined, and the resulting equations are compared and tested for a variety of standard problems. The book develops the topic starting from the basic description of an ideal gas, over the derivation of the Boltzmann equation, towards the various methods for deriving macroscopic transport equations, and the test problems which include stability of the equations, shock waves, and Couette flow.
Macroscopic Description Of Rarefied Gas Flows In The Transition Regime
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Author : Peyman Taheri Bonab
language : en
Publisher:
Release Date : 2010
Macroscopic Description Of Rarefied Gas Flows In The Transition Regime written by Peyman Taheri Bonab and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
The fast-paced growth in microelectromechanical systems (MEMS), microfluidic fabrication, porous media applications, biomedical assemblies, space propulsion, and vacuum technology demands accurate and practical transport equations for rarefied gas flows. It is well-known that in rarefied situations, due to strong deviations from the continuum regime, traditional fluid models such as Navier-Stokes-Fourier (NSF) fail. The shortcoming of continuum models is rooted in nonequilibrium behavior of gas particles in miniaturized and/or low-pressure devices, where the Knudsen number (Kn) is sufficiently large. Since kinetic solutions are computationally very expensive, there has been a great desire to develop macroscopic transport equations for dilute gas flows, and as a result, several sets of extended equations are proposed for gas flow in nonequilibrium states. However, applications of many of these extended equations are limited due to their instabilities and/or the absence of suitable boundary conditions. In this work, we concentrate on regularized 13-moment (R13) equations, which are a set of macroscopic transport equations for flows in the transition regime, i.e., Kn?1. The R13 system provides a stable set of equations in Super-Burnett order, with a great potential to be a powerful CFD tool for rarefied flow simulations at moderate Knudsen numbers. The goal of this research is to implement the R13 equations for problems of practical interest in arbitrary geometries. This is done by transformation of the R13 equations and boundary conditions into general curvilinear coordinate systems. Next steps include adaptation of the transformed equations in order to solve some of the popular test cases, i.e., shear-driven, force-driven, and temperature-driven flows in both planar and curved flow passages. It is shown that inexpensive analytical solutions of the R13 equations for the considered problems are comparable to expensive numerical solutions of the Boltzmann equation. The new results present a wide range of linear and nonlinear rarefaction effects which alter the classical flow patterns both in the bulk and near boundary regions. Among these, multiple Knudsen boundary layers (mechanocaloric heat flows) and their influence on mass and energy transfer must be highlighted. Furthermore, the phenomenon of temperature dip and Knudsen paradox in Poiseuille flow; Onsager's reciprocity relation, two-way flow pattern, and thermomolecular pressure difference in simultaneous Poiseuille and transpiration flows are described theoretically. Through comparisons it is shown that for Knudsen numbers up to 0.5 the compact R13 solutions exhibit a good agreement with expensive solutions of the Boltzmann equation.
Rarefied Gas Flows And Dynamic Plasma Phenomena In Electric Propulsion Systems
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Author : Juan Esteban Gomez Herrera
language : en
Publisher: Cuvillier Verlag
Release Date : 2020-12-01
Rarefied Gas Flows And Dynamic Plasma Phenomena In Electric Propulsion Systems written by Juan Esteban Gomez Herrera and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-12-01 with Science categories.
Zu den aktuellen Entwicklungen in der Raumfahrtindustrie zählen das stetig wachsende Interesse an miniaturisierten Satelliten sowie der immer häufigere Einsatz elektrischer Antriebssysteme zu allgemeinen Lage- und Bahnregelungszwecken. Die Entwicklung miniaturisierter Satelliten erfordert ihrerseits den Einsatz von Antriebssystemen, die sehr kleine und präzise zu steuernde Schubkräfte erzeugen. Vor diesem Hintergrund stellen elektrische Triebwerke eine attraktive Option dar, die Antriebsanforderungen von Satelliten sowohl in herkömmlichen als auch in miniaturisierten Größen langfristig zu erfüllen. Bei miniaturisierten Satelliten sind die Schubanforderungen oft mit niedrigen Treibstoff-Massenstromwerten und verhältnismäßig kleinen geometrischen charakteristischen Längen verbunden. Dies kann zu verdünnten Gaszuständen innerhalb der Triebwerksdüsen führen. Wegen der hohen Komplexität der Plasmaphänomene innerhalb elektrischer Triebwerke sowie der typischerweise hohen Rechenanforderungen, die mit der Plasmamodellierung einhergehen, werden elektrische Antriebssysteme oft auf Basis empirischer Modelle und experimenteller Daten entwickelt. Der Fokus der vorliegenden Arbeit liegt auf den oben beschriebenen Herausforderungen und den dazugehörigen Forschungsfeldern: der Untersuchung verdünnter Gaszustände in transsonischen Strömungen sowie der Entwicklung numerischer Modellierungsansätze zur Beschreibung des Plasmaverhaltens innerhalb elektrischer Antriebssysteme. New trends regarding fundamental design approaches of orbital spacecraft have been developing in the space industry in recent years. They include an increased interest in miniaturized satellites as well as a general rise in the use of electric propulsion systems for orbit and attitude control. The successful implementation of miniaturized satellites requires the use of propulsion devices able to provide small and precise thrust and impulse levels. One technical solution able to meet the requirements of both standard-sized as well as miniaturized spacecraft involves the use of highly efficient and precise electric propulsion systems. In the particular case of miniaturized satellites, the propulsion requirements are often associated with low propellant mass flow rates and small characteristic geometrical lengths, potentially leading to the appearance of rarefied conditions inside the nozzles of the propulsion devices. Because of the high complexity of the plasma phenomena taking place inside such systems and the usually very high computational requirements associated with their numerical modelling, electric propulsion systems for space applications are usually designed based on empirical models and experimental data. The present work focuses on two key aspects outlined above: rarefied gas conditions in transonic micronozzle flows as well as the numerical modelling of plasma phenomena inside electric propulsion systems.
Radiation Gas Dynamics
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Author : Shih-I. Pai
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Radiation Gas Dynamics written by Shih-I. Pai and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
When the temperature of a gas is not too high and the density of a gas is not too low, the transfer of heat by radiation is usually negligibly small in comparison with that by conduction and convection. However, in the hypersonic flow of space flight, particularly in the re-entry of a space vehicle, and in the flow problem involving nuclear reaction such as in the blast wave of nuclear bomb or in the peaceful use of the controlled fusion reaction, the temperature of the gas may be very high and the density of the gas may be very low. As a result, thermal radiation becomes a very important mode of heat transfer. A complete analysis of such high temperature flow fields should be based upon a study of the gasdynamic field and the radiation field simultaneously. Hence during the last few years, considerable efforts have been made to study such interaction problems between gasdynamic field and radiation field and a new title, Radiation Gasdynamics, has been suggested for this subject. Even though radiative transfer has been studied for a long time by astro physicists, the interaction between the radiation field and the gadsynamic field has been only extensively studied recently.
Heat Transfer
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Author : Aziz Belmiloudi
language : en
Publisher: BoD – Books on Demand
Release Date : 2011-01-28
Heat Transfer written by Aziz Belmiloudi and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-01-28 with Science categories.
Over the past few decades there has been a prolific increase in research and development in area of heat transfer, heat exchangers and their associated technologies. This book is a collection of current research in the above mentioned areas and discusses experimental, theoretical and calculation approaches and industrial utilizations with modern ideas and methods to study heat transfer for single and multiphase systems. The topics considered include various basic concepts of heat transfer, the fundamental modes of heat transfer (namely conduction, convection and radiation), thermophysical properties, condensation, boiling, freezing, innovative experiments, measurement analysis, theoretical models and simulations, with many real-world problems and important modern applications. The book is divided in four sections : "Heat Transfer in Micro Systems", "Boiling, Freezing and Condensation Heat Transfer", "Heat Transfer and its Assessment", "Heat Transfer Calculations", and each section discusses a wide variety of techniques, methods and applications in accordance with the subjects. The combination of theoretical and experimental investigations with many important practical applications of current interest will make this book of interest to researchers, scientists, engineers and graduate students, who make use of experimental and theoretical investigations, assessment and enhancement techniques in this multidisciplinary field as well as to researchers in mathematical modelling, computer simulations and information sciences, who make use of experimental and theoretical investigations as a means of critical assessment of models and results derived from advanced numerical simulations and improvement of the developed models and numerical methods.
Canadian Journal Of Physics
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Author :
language : en
Publisher:
Release Date : 2013
Canadian Journal Of Physics written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Physics categories.
Parallel Computational Fluid Dynamics
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Author : Rupak Biswas
language : en
Publisher: DEStech Publications, Inc
Release Date : 2010
Parallel Computational Fluid Dynamics written by Rupak Biswas and has been published by DEStech Publications, Inc this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Computers categories.
Analysis And Numerics For Conservation Laws
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Author : Gerald Warnecke
language : en
Publisher: Springer Science & Business Media
Release Date : 2005-12-05
Analysis And Numerics For Conservation Laws written by Gerald Warnecke and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-12-05 with Mathematics categories.
Whatdoasupernovaexplosioninouterspace,?owaroundanairfoil and knocking in combustion engines have in common? The physical and chemical mechanisms as well as the sizes of these processes are quite di?erent. So are the motivations for studying them scienti?cally. The super- 8 nova is a thermo-nuclear explosion on a scale of 10 cm. Astrophysicists try to understand them in order to get insight into fundamental properties of the universe. In ?ows around airfoils of commercial airliners at the scale of 3 10 cm shock waves occur that in?uence the stability of the wings as well as fuel consumption in ?ight. This requires appropriate design of the shape and structure of airfoils by engineers. Knocking occurs in combustion, a chemical 1 process, and must be avoided since it damages motors. The scale is 10 cm and these processes must be optimized for e?ciency and environmental conside- tions. The common thread is that the underlying ?uid ?ows may at a certain scale of observation be described by basically the same type of hyperbolic s- tems of partial di?erential equations in divergence form, called conservation laws. Astrophysicists, engineers and mathematicians share a common interest in scienti?c progress on theory for these equations and the development of computational methods for solutions of the equations. Due to their wide applicability in modeling of continua, partial di?erential equationsareamajor?eldofresearchinmathematics. Asubstantialportionof mathematical research is related to the analysis and numerical approximation of solutions to such equations. Hyperbolic conservation laws in two or more spacedimensionsstillposeoneofthemainchallengestomodernmathematics.
Advanced Computational Methods And Experiments In Heat Transfer Xi
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Author : Bengt Sundén
language : en
Publisher: WIT Press
Release Date : 2010
Advanced Computational Methods And Experiments In Heat Transfer Xi written by Bengt Sundén and has been published by WIT Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Technology & Engineering categories.
.".. Eleventh International Conference on Advanced Computational Methods and Experimental Measurements in Heat Transfer and Mass Transfer held in Tallinn, Estonia in 2010"--Pref.
Rarefied Gas Dynamics
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Author : M. N. Kogan
language : en
Publisher: Springer
Release Date : 1969
Rarefied Gas Dynamics written by M. N. Kogan and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1969 with Science categories.