Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Development Of A Fluid Model For Dc Arc Plasma Torches And Its Integration With Downstream Models Of Atmospheric Plasma Spray Particle Plumes
Download Development Of A Fluid Model For Dc Arc Plasma Torches And Its Integration With Downstream Models Of Atmospheric Plasma Spray Particle Plumes full books in PDF, epub, and Kindle. Read online Development Of A Fluid Model For Dc Arc Plasma Torches And Its Integration With Downstream Models Of Atmospheric Plasma Spray Particle Plumes ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Development of a Fluid Model for DC Arc Plasma Torches and Its Integration with Downstream Models of Atmospheric Plasma Spray Particle Plumes by : Michael J. Cannamela
Download or read book Development of a Fluid Model for DC Arc Plasma Torches and Its Integration with Downstream Models of Atmospheric Plasma Spray Particle Plumes written by Michael J. Cannamela and published by . This book was released on 2013 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The plasma spray process uses plasma flames to melt micron sized particles of e.g. ceramic and propel the droplets to impinge upon and freeze to the target workpiece, forming a functional coating. Variations in the process arise from many sources, and because sensing of the process is imperfect one is motivated to pursue a modeling approach. This dissertation models the major elements of the process; the torch that produces the plasma flame, the jet of hot plasma issuing from the torch, and the plume of particles conveyed and heated by the jet. The plasma in the torch is modeled by a one-fluid magnetohydrodynamic (MHD) approach and it is found that the MHD equations can accurately predict the power dissipated in the bulk of the plasma, while special treatment is required in regions near the electrodes. Treatment of the cathode region is eased since it can be de-coupled from the bulk flow. Treatment of the anode region aims to extract the correct amount of power from the plasma. With MHD in the bulk and these special conditions at the electrode boundaries, the net power into the plasma can be matched with experiment. For one simulation of an SG-100 torch operating at 500A, the measured net power was 7.0kW while the computed net power was 7.1kW. Using outlet information from the torch, the impact of plasma arc oscillations on the free jet and on the in-flight particle states is predicted. The model of the plasma jet is validated against the existing LAVA code, and is able to predict the fraction of entrained air in the jet to within 20% of the experimental value. The variations in particle states due to the arc fluctuations are found to be similar in size to variations due to changes in particle injection velocity, and so cannot be neglected when considering particle state distributions. The end result of this work is to make available a complete chain of models for the plasma spray process, from torch input conditions to in-flight particle state.
Book Synopsis Handbook of Thermal Plasmas by : Maher I. Boulos
Download or read book Handbook of Thermal Plasmas written by Maher I. Boulos and published by Springer Nature. This book was released on 2023-02-20 with total page 1973 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative reference presents a comprehensive review of the evolution of plasma science and technology fundamentals over the past five decades. One of this field’s principal challenges has been its multidisciplinary nature requiring coverage of fundamental plasma physics in plasma generation, transport phenomena under high-temperature conditions, involving momentum, heat and mass transfer, and high-temperature reaction kinetics, as well as fundamentals of material science under extreme conditions. The book is structured in five distinct parts, which are presented in a reader-friendly format allowing for detailed coverage of the science base and engineering aspects of the technology including plasma generation, mathematical modeling, diagnostics, and industrial applications of thermal plasma technology. This book is an essential resource for practicing engineers, research scientists, and graduate students working in the field.
Book Synopsis Numerical and Experimental Study of the Arc Fluctuations in a DC Plasma Torch by : Esmaeil Safaei Ardakani
Download or read book Numerical and Experimental Study of the Arc Fluctuations in a DC Plasma Torch written by Esmaeil Safaei Ardakani and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: When the arc voltage fluctuates inside the torch, the velocity and temperature are subject to fluctuation, creating fluctuating temperature and velocity profiles at the torch outlet. This means that the particles experience different conditions, preventing uniform particle acceleration, heating, and melting, that can reduce the coating quality. Comprehensive three-dimensional unsteady state models of DC argon and argon-hydrogen plasma torches were developed. The arc root attachment point was calculated based on matching experimental voltage fluctuations with arc length estimations from steady state models. Unsteady state results show velocity at torch outlet can fluctuate by up to 30%. The fluctuating velocity and temperature profiles were used to study the plasma jet and particle heating, because a steady state model of a plasma jet cannot predict particle heating. It was demonstrated that the unsteady model could accurately predict both particle temperature and velocity. The comprehensive simulation model that was built in this research was also used to conduct a new study on a Blue torch, a new design of conventional plasma torches, the plasma gas is composed of argon, carbon dioxide, and methane. The results of these simulations show that shrinking the length of the blue torch results in better torch efficiency. The temperature and velocity fluctuations at torch outlet is less than the ones observed in conventional torches, due to the nature of plasma mixture, and the longer chamber. The present study is one of the first research works that studies the effect of arc fluctuations on Turbulence Kinetic Energy (TKE) production. The results show that arc fluctuations, and thus velocity fluctuations at torch outlet, have a considerable effect on TKE. This study presents a structured framework for modeling the plasma torch. The simulation model is well developed, and produces results that are in good agreement with both electrical and thermal empirical. The results help us get a better understanding of plasma torch, plasma jet stream, and particle heating, which leads to a more clear and accurate image of plasma torch performance.
Book Synopsis A Turbulent Swirling Arc Model and a Two-fluid Turbulence Model for Thermal Plasma Sprays by : Po-chuan Huang
Download or read book A Turbulent Swirling Arc Model and a Two-fluid Turbulence Model for Thermal Plasma Sprays written by Po-chuan Huang and published by . This book was released on 1993 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Finite Element Modeling of Flow Instabilities in Arc Plasma Torches by : Juan Pablo Trelles
Download or read book Finite Element Modeling of Flow Instabilities in Arc Plasma Torches written by Juan Pablo Trelles and published by . This book was released on 2013 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: The further development of thermal plasma technologies has been limited by the incomplete understanding of instabilities occurring when a confined electric arc interacts with a flow of processing gas. Particularly, plasma spraying, one of the most versatile and widely used spray technologies, suffers from occasional lack of reproducibility due to the partial comprehension of the arc dynamics inside the torch. This research is motivated by the need to obtain fundamental knowledge of the dynamics of the arc inside a plasma torch due to its interaction with a flow of processing gas, and to improve thermal plasma processes in which the flow instabilities preclude their control and uniformity. This thesis presents the development and implementation of two models capable of describing the dynamic arc behavior inside plasma torches; one based on the Local Thermodynamic Equilibrium (LTE) assumption and another based on a more complete description of the plasma that allows partial kinetic equilibration between electrons and heavy particles (Non-LTE or NLTE). The fluid and electromagnetic equations describing both models are approximated numerically in a fully-coupled approach by a Variational Multi-scale Finite Element Method (VMS-FEM), which implicitly accounts for the multi-scale nature of the plasma flow and is promising for the modeling of complex multi-physics and multi-scale phenomena. The solution of the discrete system arising from the VMS-FEM formulation is obtained by a fully-implicit predictor multi-corrector time integrator together with a globalized Newton-Krylov method. The models are applied to the three-dimensional and time-dependent simulation of flow instabilities inside a commercial arc plasma torch typically used in plasma spraying processes, operating with argon and argon-helium. A reattachment model is developed to mimic the physical process by which the arc forms a new attachment under certain operating conditions. A detailed comparison between the results from the NLTE and LTE models is presented, and the role of instabilities on the arc dynamics is elucidated. In contrast to the LTE model, the NLTE model did not need a separate reattachment model to produce the arc reattachment process. The non-equilibrium results show large non-equilibrium zones in the plasma - cold-flow interaction region and close to the anode surface. Marked differences in the arc dynamics, especially in the arc reattachment process, and in the magnitudes of the total voltage drop and outlet temperatures and velocities between the models are observed. The non-equilibrium results show improved agreement with experimental observations.
Book Synopsis Three-Dimensional Modeling of Arc Voltage Fluctuations in Suspension Plasma Spraying by : Elham Dalir
Download or read book Three-Dimensional Modeling of Arc Voltage Fluctuations in Suspension Plasma Spraying written by Elham Dalir and published by . This book was released on 2016 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considering the wide range of plasma jet applications including plasma cutting, plasma spraying, and plasma arc waste disposal, realistic simulation of a plasma jet would significantly help to better understand and improve various processes. In this research, firstly a three-dimensional DC plasma torch is modeled using Joule effect method to simulate the plasma jet and its voltage fluctuations. The plasma gas is a mixture of argon/hydrogen and the arc voltage fluctuation is used as an input data in the model. Physical and chemical properties of plasma gases are used to model the plasma jet having high temperature and velocity. Reynolds Stress Model is used for time dependent simulation of the mixing flow of the plasma gas with atmosphere. After modeling the plasma jet, the results are applied to investigate the plasma oscillation effects on the trajectory, temperature, and velocity of suspension droplets. Suspensions are formed of ethanol and Yttria Stabilized Zirconia (YSZ, 8 wt.%) sub-micron particles and modeled as multicomponent droplets. To track the droplets and particles trajectory, a two-way coupled Eulerian-Lagrangian method is employed. In addition, in order to simulate the droplet breakup, Kelvin-Helmholtz Rayleigh-Taylor (KHRT) breakup model is used. After the completion of suspension breakup and evaporation, the spray particles are tracked through the domain to obtain the in-flight particle characteristics.
Book Synopsis Analysis of the Plasma Jet Structure, Particle Motion, and Coating Quality During DC Plasma Spraying by : Stuart John Malmberg
Download or read book Analysis of the Plasma Jet Structure, Particle Motion, and Coating Quality During DC Plasma Spraying written by Stuart John Malmberg and published by . This book was released on 1994 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling the Non-transferred Arc Plasma Torch and Plume for Plasma Processing by : Richard Westhoff
Download or read book Modeling the Non-transferred Arc Plasma Torch and Plume for Plasma Processing written by Richard Westhoff and published by . This book was released on 1992 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Solution to Phase Change Problem by : Amirsaman Farrokhpanah
Download or read book Numerical Solution to Phase Change Problem written by Amirsaman Farrokhpanah and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of flight, impact, and solidification of molten ceramic droplets generated by suspension plasma spraying (SPS) is conducted. A three-dimensional model is developed for predicting behavior of droplets generated by SPS impacting a solid substrate. The model combines Smoothed Particle Hydrodynamics (SPH) integral interpolations with enthalpy formulations to capture the phase change process (solidification/melting). Surface tension is modeled as an internal force between all particles, that will be canceled in the bulk of fluid and generate unbalanced surface tension forces near the free surface. A Finite-Volume solver is also used to predict properties of the droplets at the time of reaching the substrate, i.e. temperature, velocity, and diameter. This solver uses discrete phase models to track flight, evaporation, and atomization of suspension droplets injected into plasma flow. Effects of high temperature gradients and non-continuum on solid particles in plasma flow are taken into account. Results are presented here in three steps. First, the newly developed numerical models for capturing solidification/melting in SPH are validated among various experimental, analytical, and numerical results from literature. These phase change models mainly fall into two main categories: (1) inclusion of latent heat as a source term in the enthalpy equation, (2) inclusion of latent heat by modifying the effective heat capacity in the enthalpy equation. Results confirm accuracy and robustness of the new methods. Secondly, results for droplet generation in SPS are presented. Effects of different parameters on droplets flight and impact are investigated. The goal here is to find suitable operating conditions for the plasma torch and injection process that guarantee impact of high quality droplets on the surface. Effects of injector parameters like injection location, flow rate, and angle along with effects of change in physical properties of droplets are studied. Finally, the newly improved SPH model is used to predict impact of molten ceramic droplets that are collected on the substrate. These cases include predictions for the spread factor and droplet behavior based on their impact velocity and temperature. Results are used to explain different scenarios happening in substrate coating using SPS.
Book Synopsis Thermal Spray Fundamentals by : Pierre L. Fauchais
Download or read book Thermal Spray Fundamentals written by Pierre L. Fauchais and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 1587 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides readers with the fundamentals necessary for understanding thermal spray technology. Coverage includes in-depth discussions of various thermal spray processes, feedstock materials, particle-jet interactions, and associated yet very critical topics: diagnostics, current and emerging applications, surface science, and pre and post-treatment. This book will serve as an invaluable resource as a textbook for graduate courses in the field and as an exhaustive reference for professionals involved in thermal spray technology.
Book Synopsis Experimental and Modeling Analysis of Plasma Spray Nonlinearities for Advanced Process Control Design by : Chenhuan Cui
Download or read book Experimental and Modeling Analysis of Plasma Spray Nonlinearities for Advanced Process Control Design written by Chenhuan Cui and published by . This book was released on 2007 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: To determine the torch input/output dynamic characteristics for different operating torch conditions, a series of open-loop experiments were conducted. The nonlinear behavior of the process open-loop gains and dynamics are identified as important problems for development of a viable process control strategy design.
Book Synopsis Modelling of a D.C. Arc Plasma Torch with a Hydrogen-argon Mixture as the Working Gas by : X. Chen
Download or read book Modelling of a D.C. Arc Plasma Torch with a Hydrogen-argon Mixture as the Working Gas written by X. Chen and published by . This book was released on 2000 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermal Plasma Torches and Technologies by : O. P. Solonenko
Download or read book Thermal Plasma Torches and Technologies written by O. P. Solonenko and published by Cambridge Int Science Publishing. This book was released on 2000 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 1 of a two-volume work publishes studies of scientific from a number of countries in the area of plasma torch design and properties. Topics covered include mathematical modelling of transformer discharge, physical phenomena in a hollow cathode, modelling of electric arc plasma, problems of turbulent arc modelling, erosion of multiarc cathodes, integrated methods of research of processes in thermal plasma, trends in thermal plasma technology, plasma metallurgy, analysis of induction plasma systems, and many others.
Book Synopsis Plasma Jet Technology by : P. R. Dennis
Download or read book Plasma Jet Technology written by P. R. Dennis and published by . This book was released on 1965 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Sun, the Earth, and Near-earth Space by : John A. Eddy
Download or read book The Sun, the Earth, and Near-earth Space written by John A. Eddy and published by Government Printing Office. This book was released on 2009 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: " ... Concise explanations and descriptions - easily read and readily understood - of what we know of the chain of events and processes that connect the Sun to the Earth, with special emphasis on space weather and Sun-Climate."--Dear Reader.
Book Synopsis Low Temperature Plasma Technology by : Paul K. Chu
Download or read book Low Temperature Plasma Technology written by Paul K. Chu and published by CRC Press. This book was released on 2013-07-15 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a team of pioneering scientists from around the world, Low Temperature Plasma Technology: Methods and Applications brings together recent technological advances and research in the rapidly growing field of low temperature plasmas. The book provides a comprehensive overview of related phenomena such as plasma bullets, plasma penetration into biofilms, discharge-mode transition of atmospheric pressure plasmas, and self-organization of microdischarges. It describes relevant technology and diagnostics, including nanosecond pulsed discharge, cavity ringdown spectroscopy, and laser-induced fluorescence measurement, and explores the increasing research on atmospheric pressure nonequilibrium plasma jets. The authors also discuss how low temperature plasmas are used in the synthesis of nanomaterials, environmental applications, the treatment of biomaterials, and plasma medicine. This book provides a balanced and thorough treatment of the core principles, novel technology and diagnostics, and state-of-the-art applications of low temperature plasmas. It is accessible to scientists and graduate students in low-pressure plasma physics, nanotechnology, plasma medicine, and materials science. The book is also suitable as an advanced reference for senior undergraduate students.
Book Synopsis Environmental Barrier Coatings by : Kang N. Lee
Download or read book Environmental Barrier Coatings written by Kang N. Lee and published by MDPI. This book was released on 2020-12-29 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The global increase in air travel will require commercial vehicles to be more efficient than ever before. Advanced engine hot section materials are a key technology required to keep fuel consumption and emission to a minimum in next-generation gas turbines. Ceramic matrix composites (CMCs) are the most promising material to revolutionize gas turbine hot section materials technology because of their excellent high‐temperature properties. Rapid surface recession due to volatilization by water vapor is the Achilles heel of CMCs. Environmental barrier coatings (EBCs) is an enabling technology for CMCs, since it protects CMCs from water vapor. The first CMC component entered into service in 2016 in a commercial engine, and more CMC components are scheduled to follow within the next few years. One of the most difficult challenges to CMC components is EBC durability, because failure of EBC leads to a rapid reduction in CMC component life. Key contributors to EBC failure include recession, oxidation, degradation by calcium‐aluminum‐magnesium silicates (CMAS) deposits, thermal and thermo‐mechanical strains, particle erosion, and foreign object damage (FOD). Novel EBC chemistries, creative EBC designs, and robust processes are required to meet EBC durability challenges. Engine-relevant testing, characterization, and lifing methods need to be developed to improve EBC reliability. The aim of this Special Issue is to present recent advances in EBC technology to address these issues. In particular, topics of interest include but are not limited to the following: • Novel EBC chemistries and designs; • Processing including plasma spray, suspension plasma spray, solution precursor plasma spray, slurry process, PS-PVD, EB-PVD, and CVD; • Testing, characterization, and modeling; • Lifing.
