Author: Konstantinos Koutsakis
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Konstantinos Koutsakis
Publisher:
ISBN:
Category :
Languages : en
Pages : 135

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Author: Efstathios E. Michaelides
Publisher: CRC Press
ISBN: 1000790576
Category : Technology & Engineering
Languages : en
Pages : 478

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Book Description
Multiphase Flows with Droplets and Particles provides an organized, pedagogical study of multiphase flows with particles and droplets. This revised edition presents new information on particle interactions, particle collisions, thermophoresis and Brownian movement, computational techniques and codes, and the treatment of irregularly shaped particles. An entire chapter is devoted to the flow of nanoparticles and applications of nanofluids. Features Discusses the modelling and analysis of nanoparticles. Covers all fundamental aspects of particle and droplet flows. Includes heat and mass transfer processes. Features new and updated sections throughout the text. Includes chapter exercises and a Solutions Manual for adopting instructors. Designed to complement a graduate course in multiphase flows, the book can also serve as a supplement in short courses for engineers or as a stand-alone reference for engineers and scientists who work in this area.

Author: Mehdi Jadidi
Publisher:
ISBN:
Category :
Languages : en
Pages : 176

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Book Description
Fine microstructured coatings have attracted many attentions in recent years due to various unique properties such as remarkable wear resistance, enhanced catalytic behavior, and superior thermal insulation. Suspension thermal sprays have been shown to be viable techniques in generating this kind of coatings. In these techniques, suspension which is a combination of a base liquid and fine solid particles is injected into a high-temperature high-velocity jets. After suspension breakup, the evaporation/combustion of base liquid becomes dominant. Then, the remained particles are accelerated and heated up by the gas flow and are deposited on a substrate which results in the generation of dense and well-adhered coatings. Suspension thermal spraying is very complex and many fields such as turbulent flow, multiphase flow, compressible flow, combustion, atomization, suspension properties, and plasma physics are involved in the mentioned technique. In addition, many parameters and mechanisms in this technique are still unknowns. Therefore, both numerical and experimental studies should be performed to obtain a comprehensive understanding of various phenomena in suspension thermal spraying and to improve the coating quality. The main goal of this study is the numerical modeling of suspension thermal sprays. An Eulerian-Lagrangian approach with two-way coupling assumption is presented and suspension droplet evolution in the atmospheric plasma spraying and high velocity oxygen fuel spraying techniques is investigated. In this model, suspension is considered as a multi-component mixture and a predefined droplet distribution is injected into the jet. In this approach, the breakup process is simulated using Taylor Analogy Breakup (TAB), and Kelvin-Helmholtz Rayleigh-Taylor (KHRT) breakup models. After breakup process is complete, the liquid component of suspension droplet evaporates/burns, and the particles/agglomerates are tracked in the domain. In general, the effects of suspension injection velocity, suspension properties, suspension injector location, standoff distance, substrate shape, and gas properties on the coating characteristics can be investigated by this approach. For example, in the case of radial injection of suspension into a plasma plume, it is illustrated that if particles move close to the jet centerline, particle velocity and temperature as well as probability of particle impact on the substrate will increase. The mentioned Eulerian-Lagrangian approach revealed that the breakup phenomenon mainly controls the droplets/particles trajectories, temperatures and velocities. However, the typical TAB and KHRT models ignore liquid/suspension column deformation, and need experimental calibration. To study the breakup process in more details, the effect of nonuniform gaseous crossflow and liquid column perturbations on the primary breakup of liquid jets are investigated. A coupled level set and volume-of-fluid method together with the large eddy simulation turbulence model are used to study the behavior of nonturbulent liquid jets in nonuniform crossflows. It is shown that liquid penetration height is significantly affected by the crossflow nonuniformity. In addition, to investigate the effects of liquid column perturbations on the breakup process, experimental studies are performed using shadowgraphy technique. General correlations for the penetration height, the column breakup point, and the onset of surface breakup are presented. It is found that the liquid column perturbations result in formation of large ligaments very close to the liquid and gas flows interaction point. These ligaments control the droplet size distribution and have significant effects on particle in-flight behavior, and coatings quality. The results of these studies can be used to estimate the spray trajectory in suspension plasma spray process, and to improve the accuracy of TAB and KHRT breakup models.

Author: Guan Heng Yeoh
Publisher: Butterworth-Heinemann
ISBN: 0080982336
Category : Science
Languages : en
Pages : 385

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Book Description
Written by leading multiphase flow and CFD experts, this book enables engineers and researchers to understand the use of PBM and CFD frameworks. Population balance approaches can now be used in conjunction with CFD, effectively driving more efficient and effective multiphase flow processes. Engineers familiar with standard CFD software, including ANSYS-CFX and ANSYS–Fluent, will be able to use the tools and approaches presented in this book in the effective research, modeling and control of multiphase flow problems. - Builds a complete understanding of the theory behind the application of population balance models and an appreciation of the scale-up of computational fluid dynamics (CFD) and population balance modeling (PBM) to a variety of engineering and industry applications in chemical, pharmaceutical, energy and petrochemical sectors - The tools in this book provide the opportunity to incorporate more accurate models in the design of chemical and particulate based multiphase processes - Enables readers to translate theory to practical use with CFD software

Author: Clayton T. Crowe
Publisher: CRC Press
ISBN: 9780849394690
Category : Technology & Engineering
Languages : en
Pages : 492

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Book Description
Multiphase flow technology, especially in the area of gas-droplet and gas-particle flows, is increasingly important in the energy and manufacturing industries. Pollution control, pneumatic transport, food processing, combustion, and development of new materials as well as many other engineering applications will benefit from the fundamental engineering design applications and research in this field. Written for graduate students and professionals, Multiphase Flows with Droplets and Particles provides a clear, pedagogical approach to the fundamentals of gas-particle and gas-droplet flows.

Author: Andrea Alberto Mammoli
Publisher: WIT Press
ISBN: 1845640306
Category : Science
Languages : en
Pages : 385

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Book Description
A common feature of multiphase flows is that a dispersed or discontinuous phase is being carried by a continuous phase, for example water drops in gas flow, solid particles in water flow, or gas bubbles in liquid flow. The overall behavior of the flow is shaped largely by the interaction between the discontinuous elements--drops, particles, bubbles

Author: Elham Dalir
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Suspension plasma spraying (SPS), a relatively new deposition technique in thermal spray coating technology, has been increasingly applied to deposit high-quality thermal barrier coatings using sub-micron particles. An accurate simulation of the process includes developing a realistic plasma model both within and outside the torch. In the current work, a three-dimensional time-dependent model has been developed to simulate magneto-hydrodynamic fields inside a direct current (DC) plasma torch, including arc fluctuations. Reynolds stress model (RSM) is used to simulate the time-dependent turbulent plasma flow. A two-way coupled Eulerian-Lagrangian method is employed to investigate the effects of arc fluctuations on the droplets' trajectory, temperature, and speed. Sub-micron yttria-stabilized zirconia (YSZ) solid particles suspended into ethanol are modeled as multicomponent droplets. Kelvin-Helmholtz Rayleigh-Taylor (KHRT) breakup model is used to simulate the droplets' atomization. This model considers the effects of both aerodynamic forces (Wave model) and Rayleigh-Taylor instabilities on the atomization process combing a liquid core region (Levich model). Particles are also tracked after completion of suspension breakup and evaporation to obtain inflight particles' conditions (trajectory, size, speed, and temperature). The developed model is then employed to study the droplets' shape and solid concentration on the SPS process. A dynamic drag law is applied to analyze the effect of droplets/particles' shape on the SPS process. It was concluded that the percentage of molten particles in applying dynamic drag law (non-spherical particles) decreases significantly compared to using the spherical particles. The effect of suspension concentration is also studied. It was shown that using a higher solid concentration (20 compared to 10 wt.% YSZ) provides a denser coating as a result of the larger molten landed particles with higher velocities. Finally, the developed model is used to study the in-flight droplets/particles' atomization in the SPS process. Nine case studies are investigated to see the effect of KH, RT instabilities, and breakup length on the droplets/particles' atomization. A massive difference is represented in quantity, droplets' atomization pattern, and quality of the final landed particles over the substrate of some cases. The obtained size distributions of the trapped particles over the substrate are compared to the existing data to find the suggested ranges for the breakup model's constants.

Author: Moubin Liu
Publisher: World Scientific
ISBN: 9814571717
Category : Mathematics
Languages : en
Pages : 400

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Book Description
Multi-scale and multi-physics modeling is useful and important for all areas in engineering and sciences. Particle Methods for Multi-Scale and Multi-Physics systematically addresses some major particle methods for modeling multi-scale and multi-physical problems in engineering and sciences. It contains different particle methods from atomistic scales to continuum scales, with emphasis on molecular dynamics (MD), dissipative particle dynamics (DPD) and smoothed particle hydrodynamics (SPH).This book covers the theoretical background, numerical techniques and many interesting applications of the particle methods discussed in this text, especially in: micro-fluidics and bio-fluidics (e.g., micro drop dynamics, movement and suspension of macro-molecules, cell deformation and migration); environmental and geophysical flows (e.g., saturated and unsaturated flows in porous media and fractures); and free surface flows with possible interacting solid objects (e.g., wave impact, liquid sloshing, water entry and exit, oil spill and boom movement). The presented methodologies, techniques and example applications will benefit students, researchers and professionals in computational engineering and sciences.

Author: Daniele L. Marchisio
Publisher: Springer Science & Business Media
ISBN: 3211724648
Category : Technology & Engineering
Languages : en
Pages : 269

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Book Description
This book describes the most widely applicable modeling approaches. Chapters are organized in six groups covering from fundamentals to relevant applications. The book covers particle-based methods and also discusses Eulerian-Eulerian and Eulerian-Lagrangian techniques based on finite-volume schemes. Moreover, the possibility of modeling the poly-dispersity of the secondary phases in Eulerian-Eulerian schemes by solving the population balance equation is discussed.