Download or read book Pulsed Plasma Generator Development and Low temperature Plasma assisted Combustion at Atmospheric Pressure written by Mathew Evans and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis presents an experimental study of the engineering and physics of high-voltage nanosecond-pulsed diffuse discharges, and their application to the enhancement of lean-premixed combustion at atmospheric pressure. The technology development in this work is focused on providing appropriate low-temperature radical pools, and the experiments are aimed at demonstrating the effect of these pools for combustion actuation. The experimental results are focused on the explanation of the physical processes associated with these discharges. The discharge propagation and emission spectrum were examined, the distribution functions of particles along internal energy levels were calculated, and the resulting enhancement of combustion was observed. This work shows that the plasma emission from fuel-lean mixtures is primarily composed of high vibrational populations of electronically excited nitrogen molecules, upon which a low-temperature is measured on the rotational manifold. Previous work shows that these low-temperature excited particles will collide with molecular oxygen, or fuel molecules, to produce species (atomic/molecular ground/excited oxygen, fragmented fuel molecules...) that accelerate chain-branching reactions in the combustion reaction mechanism. This work shows that the majority of the electronically excited vibrational states of nitrogen molecules, in a diffuse discharge, decay rapidly after the application of a high-voltage pulse. These findings set the framework for the implementation of diffuse plasma to laboratory-scale combustion enhancement. As an integral part of this work, the design and development of electrical generators that can produce such a reactive medium in large volume is included, and extensively detailed. An inexpensive solid-state pulse generator, based on commercially available amorphous ferromagnetic materials, is designed and developed to drive capacitive loads. The generator is used to produce large volumes of diffuse plasma and increase the blow off velocity of stagnation flames. To further investigate this enhancement, an optically accessible plasma burner is implemented and used for the detailed study of stagnation flame plasma actuation. This work shows that significant actuation can be provided to a flame, when diffuse plasma is placed upstream, and directly in contact with the combustion front. The displacement of the leading edge of a flame, into the fresh unburned mixture, is measured following a high-voltage actuating pulse. The displacement of the leading edge strongly points toward low-temperature reactivity enhancement. The optical and electrical characteristics of the diffuse plasma are reported for both the non-combusting and combusting flows. These provide a more accurate picture of the thermal characteristics and complex phenomena occurring in this transient discharge. Streamer propagation dynamics and coupled energy measurements are reported to provide further insight regarding the delicate balance that exists between plasma and flame sheet in this experimental configuration. It can be concluded that diffuse plasma is an effective low-temperature chemical actuation method for combustion enhancement at atmospheric pressure.To conclude this work, the first step toward high-pressure actuation of combustion with diffuse plasma was explored. The task of producing diffuse plasma above atmospheric pressure was undertaken. This work presents the development of a second solid-state pulse generator with increased power delivery capabilities. The generator is used to produce large volumes of diffuse plasma in a high-pressure vessel filled with air. It is found that diffuse plasma actuation could eventually be implemented in a high-pressure combustion experiment using this technology." --

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 488 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 i

Download or read book Emerging Developments and Applications of Low Temperature Plasma written by Shahzad, Aamir and published by IGI Global. This book was released on 2021-12-17 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low temperature plasma in medicine is a new field that rose from the research in the application of cold plasmas in bioengineering. Plasma medicine is an innovative and promising multidisciplinary novel field of research covering plasma physics, life sciences, and clinical medicine to apply physical plasma for therapeutic applications. Emerging Developments and Applications of Low Temperature Plasma explores all areas of experimental, computational, and theoretical study of low temperature and atmospheric plasmas and provides a collection of exciting new research on the fundamental aspects of low temperature and pressure plasmas and their applications. Covering topics such as carbon nanotubes, foodborne pathogens, and plasma formation, this book is an essential resource for research groups, plasma-based industries, plasma aerodynamics industries, metal and cutlery industries, medical institutions, researchers, and academicians.

Download or read book Powerful Pulsed Plasma Generators written by Victor Kolikov and published by Springer. This book was released on 2018-07-25 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents experimental and theoretical results on extremely powerful plasma generators. It addresses pulsed electrical mega-ampere arcs and the mechanisms of energy transfer from the arc into hydrogen, helium and air under pressures up to 250 MPa and currents up to 2 MA. Extreme plasma parameters and increased energy density in the arc were achieved. It was found experimentally that increasing the initial gas pressure to hundreds of MPa leads to improved arc stability, high efficiency of energy transfer from arc to gas, and plasma enthalpy growth. The data obtained data provides the basis for the development of electrophysical devices with high energy density, e.g. high intensity sources for visible, UV and X-ray irradiation for laser pumping, generators of high enthalpy plasma jets, and plasma chemical reactors.

Download or read book Optimization of Plasma Generators PG and Operational Modes of Plasma Assisted Combustion written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report results from a contract tasking Institute for High Temperature - RAS (IVTAN) as follows: Plasma assisted engine combustion is a newly developed field of basic science that brings together the fields of engine combustion physics and plasma physics. This project is devoted to a fundamental study of optimal regimes of stimulated burning of engine fuel/air mixtures by means of structural, non-equilibrium plasma formations (plasmoids). MTC, IVT RAS has significant experience in this field, and has produced breakthrough experimental results. For the first time, we have obtained stable engine combustion, stimulated by streamer HF discharge of a very poor fuel/air engine mixture (Argon: Propane=9:1), in a gas mixture engine flow. In addition, we have experimental results in gas engine flows of advanced mixtures with plasma formations. We plan to continue our research in the field of plasma assisted engine combustion with non-equilibrium plasmoids. These plasmoids will be created by highly efficient plasma generators (PG) of the following types: PG HF for creation of streamer corona discharge; PG- jet, plasma generator of erosive plasma jet; PG-Comb. Combined discharge could be created by combined PG (PG HF+ PG-jet) in a repetitive pulsed mode, and the main plasma parameters can be changed independently. Electron concentration can be controlled by the PG-jet, and the electron temperature can be controlled by the external HF electric field. The main goals of this work are to study the following: optimal radical generation in an engine fuel/air mixture by plasmoids; stability of the burning of the engine fuel/air mixture in an engine gas flow stimulated by plasma formations; advanced mixtures of engine fuel in an engine gas flow by structural plasmoids.

Download or read book Non Equilibrium Air Plasmas at Atmospheric Pressure written by K.H. Becker and published by CRC Press. This book was released on 2004-11-29 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric-pressure plasmas continue to attract considerable research interest due to their diverse applications, including high power lasers, opening switches, novel plasma processing applications and sputtering, EM absorbers and reflectors, remediation of gaseous pollutants, excimer lamps, and other noncoherent light sources. Atmospheric-pressure plasmas in air are of particular importance as they can be generated and maintained without vacuum enclosure and without any additional feed gases. Non-Equilibrium Air Plasmas at Atmospheric Pressure reviews recent advances and applications in the generation and maintenance of atmospheric-pressure plasmas. With contributions from leading international researchers, the coverage includes advances in atmospheric-pressure plasma source development, diagnostics and characterization, air plasma chemistry, modeling and computational techniques, and an assessment of the status and prospects of atmospheric-pressure air plasma applications. The extensive application sections make this book attractive for practitioners in many fields where technologies based on atmospheric-pressure air plasmas are emerging.

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.

Download or read book Atmospheric Pressure Plasma for Surface Modification written by Rory A. Wolf and published by John Wiley & Sons. This book was released on 2012-11-08 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Book's focus and intent is to impart an understanding of the practical application of atmospheric plasma for the advancement of a wide range of current and emerging technologies. The primary key feature of this book is the introduction of over thirteen years of practical experimental evidence of successful surface modifications by atmospheric plasma methods. It offers a handbook-based approach for leveraging and optimizing atmospheric plasma technologies which are currently in commercial use. It also offers a complete treatment of both basic plasma physics and industrial plasma processing with the intention of becoming a primary reference for students and professionals. The reader will learn the mechanisms which control and operate atmospheric plasma technologies and how these technologies can be leveraged to develop in-line continuous processing of a wide variety of substrates. Readers will gain an understanding of specific surface modification effects by atmospheric plasmas, and how to best characterize those modifications to optimize surface cleaning and functionalization for adhesion promotion. The book also features a series of chapters written to address practical surface modification effects of atmospheric plasmas within specific application markets, and a commercially-focused assessment of those effects.

Download or read book Plasma Assisted Combustion and Flameholding in High Speed Cavity Flows written by Joseph Aloysius Heinrichs and published by . This book was released on 2012 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis presents an experimental study of non-equilibrium, low temperature, large volume plasma assisted ignition and flameholding in high-speed, non-premixed fuel-air flows. The plasma is produced between two electrodes powered by a high-voltage, nanosecond pulse generator operated at a high pulse repetition rate. Ignition in this type of plasma occurs due to production of highly reactive radicals by electron impact excitation and dissociation, as opposed to more common thermal ignition. Previously, it has been shown that this type of plasma can reduce ignition delay time and ignition temperature. The experiments performed in this thesis focus on application of these plasmas to ignition, and flameholding in high-speed cavity flows. The experiments discussed in this thesis continue previous work using a high-speed combustion test section with a larger cavity, and the previous results are compared to the present work. Several modifications have been made to the test section and electrodes compared to the design used in previous work in order to reduce the cavity effect on the main flow and maintain diffuse plasma between the electrodes in the cavity. The electrodes used in these experiments are placed in a cavity recess, used to create a recirculation flow region with long residence time, where ignition and flameholding can occur. In order to analyze the nanosecond pulse plasma and the flame, various diagnostics were used, including current and voltage measurements, UV emission measurements, ICCD camera imaging, static pressure measurements, and time-averaged emission spectroscopy. The experiments in this thesis were performed at relatively low pressures (P=150-200 torr) using hydrogen and ethylene fuels injected into the cavity. Current and voltage measurements showed that ~1-2 mJ was coupled to the plasma by each pulse. ICCD imaging and UV emission data revealed that the plasma sustained in quiescent air was diffuse. When ethylene was injected into the cavity to ignite the flow, ICCD imaging and UV emission data showed arcing to bare metal surfaces in the test section occurred shortly after ignition, which prompted switching to hydrogen fuel. Using hydrogen, ICCD imaging and UV emission showed that the plasma remained diffuse and confined to the area between electrodes. Time-average emission spectroscopy measurements revealed that the air-flow temperature remained low until fuel was injected and ignition occurred. Pressure and UV emission measurements were used to find velocity limits within which the flow ignited. It was found that the upper limit of velocity depends strongly on the static pressure in the test section. The highest flow velocity at which combustion was achieved in H2-air flows was 270 m/s at 180 torr. This represents considerable improvement compared to previous work using nanosecond pulse discharge for ignition in cavities. Preliminary results show that plasma generation and ignition are possible using a smaller diameter electrode such that the cavity size can be further reduced, and that a supersonic flow can be produced in the present test section using a Mach 2 nozzle placed upstream of the cavity. The appendix details a study on the production of oxygen atoms using a pulsed excimer laser.

Download or read book Development and Characterization of Atmospheric Pressure Plasma Jets for Low Temperature Sintering written by Nazli Turan and published by . This book was released on 2022 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanosecond Pulsed Plasmas in Dynamic Combustion Environments written by Colin A. Pavan and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma assisted combustion (PAC) is a promising technology for extending combustion operating envelopes with a low energy cost relative to flame power. It has been investigated for use in various situations, particularly those where combustion is being performed near flammability limits imposed by equivalence ratio, residence time, etc. While the fundamental processes allowing plasma to modify combustion dynamics have been well studied, there are still many unresolved questions in determining the relative contribution of different actuation pathways in different situations (thermal enhancement, kinetic enhancement or transport-induced effects) and how the plasma will evolve and interact with the flame in a dynamic combustion environment. The plasmas being used for PAC are typically non-equilibrium and are often produced by the nanosecond repetitively pulsed discharge (NRPD) strategy. The development of these discharges is highly dependent both on applied voltage and also on the gas environment (composition, temperature, flow field, etc.). As the plasma affects the combustion, so too does the combustion affect the plasma structure and energy deposition pathways. This two-way coupling means that the plasma's ability to modify the combustion, and the mechanisms by which it achieves these effects, will vary as the environment changes due to combustion dynamics. This impact of the combustion on the plasma has received considerably less attention than the other direction of interaction, especially in environments with transient or propagating flames. The first main objective of this thesis is to explore the development of NRPDs in dynamic combustion environments and in particular how the plasma develops on the timescales of transient combustion (many accumulated pulses). This is performed first in a laminar, mesoscale platform to probe the interaction in detail, and the important insights are later shown to be relevant to high power systems of practical interest. While the impact of the plasma on the flame has been considerably better studied and the fundamental processes are well understood, there are still hurdles that must be overcome before PAC systems can begin to be designed and implemented for use outside of the laboratory. The development of versatile and flexible engineering models of the impact of the plasma will be necessary to allow system designers to make predictions about combustor operation when plasma is applied. The second main objective of this thesis is to develop such an engineering model and demonstrate its predictive capabilities across a variety of configurations. The model is developed for a laminar mesoscale platform and is shown to correctly predict the impact of the plasma in several different configurations, indicating a path forward towards physics[1]informed design of PAC systems. The model also provides important physical insight of the impact of plasma on flame, such as the role of pressure waves in disturbing the flame dynamics, even when considering uniform DBD discharges.

Download or read book OH LIF Studies of Low Temperature Plasma Assisted Oxidation and Ignition in Nanosecond Pulsed Discharge written by Inchul Choi and published by . This book was released on 2011 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In recent years, plasma assisted ignition and flame-holding in high speed flows has attracted considerable attention due to potential applications for turbojet engines and afterburners operating at high altitudes, as well as scramjet engines. Conventional methods of igniting a flow in the combustor using a spark or an arc discharge are known to be ineffective at low pressures and high flow velocities, since the ignition kernel is limited by a small volume of the spark or arc filament. Single photon LIF spectroscopy is used to study hydroxyl radical formation and loss kinetics in low temperature hydrogen-air repetitively pulsed nanosecond plasmas. Nanosecond pulsed plasmas are created in a rectangular cross section quartz channel / plasma flow reactor. Flow rates of hydrogen-air mixtures are controlled by mass flow controllers at a total pressure of 40-100 torr, initial temperature T0=300-500 K and a flow velocity of approximately u=0.1-0.8 m/sec. Two rectangular copper plate electrodes, rounded at the corners to reduce the electric field non-uniformity, are attached to the outside of the quartz channel. Repetitively pulsed plasmas are generated using a Chemical Physics Technologies (CPT) power supply which produces ~25 nanosecond pulses with ~20 kV peak voltage. Absolute hydroxyl radical mole fraction is determined as both a function of time after application of a single 25 nsec pulse, and 60 microseconds after the final pulse of a variable length "burst" of pulses. Relative LIF signal levels are put on an absolute mole fraction scale by means of calibration with a standard near-adiabatic Hencken flat flame burner at atmospheric pressure. By obtaining OH LIF data in both the plasma and the flame, and correcting for differences in the collisional quenching and Vibrational Energy Transfer (VET) rates, absolute OH mole fraction can be determined. For a single discharge pulse at 27 °C and 100 °C, the absolute OH temporal profile is found to rise rapidly during the initial ~0.1 msec after discharge initiation and decay relatively slowly, with a characteristic time scale of ~1 msec. In repetitive burst mode the absolute OH number density is observed to rise rapidly during the first approximately 10 pulses (0.25 msec), and then level off to a near steady-state plateau. In all cases a large secondary rise in OH number density is also observed, clearly indicative of ignition, with ignition delay equal to approximately 15, 10, and 5 msec, respectively, for initial temperatures of 27 °C, 100 °C, and 200 °C. Plasma kinetic modeling predictions capture this trend quantitatively.

Download or read book RF Power Semiconductor Generator Application in Heating and Energy Utilization written by Satoshi Horikoshi and published by Springer Nature. This book was released on 2020-03-26 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a specialized book for researchers and technicians of universities and companies who are interested in the fundamentals of RF power semiconductors, their applications and market penetration.Looking around, we see that products using vacuum tube technology are disappearing. For example, branch tube TVs have changed to liquid crystal TVs, and fluorescent light have turned into LED. The switch from vacuum tube technology to semiconductor technology has progressed remarkably. At the same time, high-precision functionalization, miniaturization and energy saving have advanced. On the other hand, there is a magnetron which is a vacuum tube device for generating microwaves. However, even this vacuum tube technology has come to be replaced by RF power semiconductor technology. In the last few years the price of semiconductors has dropped sharply and its application to microwave heating and energy fields will proceed. In some fields the transition from magnetron microwave oscillator to semiconductor microwave oscillator has already begun. From now on this development will progress remarkably. Although there are several technical books on electrical systems that explain RF power semiconductors, there are no books yet based on users' viewpoints on actual microwave heating and energy fields. In particular, none have been written about exact usage and practical cases, to answer questions such as "What are the advantages and disadvantages of RF power semiconductor oscillator?", "What kind of field can be used?" and the difficulty of the market and application. Based on these issues, this book explains the RF power semiconductors from the user's point of view by covering a very wide range of fields.

Download or read book Advanced Concepts and Architectures for Plasma Enabled Material Processing written by Oleg O. Baranov and published by Morgan & Claypool Publishers. This book was released on 2020-09-30 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma-based techniques are widely and successfully used across the field of materials processing, advanced nanosynthesis, and nanofabrication. The diversity of currently available processing architectures based on or enhanced by the use of plasmas is vast, and one can easily get lost in the opportunities presented by each of these configurations. This mini-book provides a concise outline of the most important concepts and architectures in plasma-assisted processing of materials, helping the reader navigate through the fundamentals of plasma system selection and optimization. Architectures discussed in this book range from the relatively simple, user-friendly types of plasmas produced using direct current, radio-frequency, microwave, and arc systems, to more sophisticated advanced systems based on incorporating and external substrate architectures, and complex control mechanisms of configured magnetic fields and distributed plasma sources.

Download or read book Elements of Plasma Technology written by Chiow San Wong and published by Springer. This book was released on 2015-12-24 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents some fundamental aspects of plasma technology that are important for beginners interested to start research in the area of plasma technology. These include the properties of plasma, methods of plasma generation and basic plasma diagnostic techniques. It also discusses several low cost plasma devices, including pulsed plasma sources such as plasma focus, pulsed capillary discharge, vacuum spark and exploding wire; as well as low temperature plasmas such as glow discharge and dielectric barrier discharge which the authors believe may have potential applications in industry. The treatments are experimental rather than theoretical, although some theoretical background is provided where appropriate. The principles of operation of these devices are also reviewed and discussed.

Download or read book Plasma Ramparts Using Metastable Molecules written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main goals of this experimental and theoretical project were to demonstrate the ability to create a uniform and diffuse nonequilibrium air plasma at atmospheric pressure, with an electron density of 10(13) cm( -3), a temperature below 2000 K, scalable to cubic meter size, with a low power budget. The Ohio State Consortium was focusing on use of efficient ionization sources, specifically e-beams and short pulse ionization wave generators, and on mitigation of electron removal by using laser energy addition to excite the vibrational modes of the air species. By this means, the power budget to sustain a stable plasma in low temperature, atmospheric pressure air is significantly reduced. The plasma decay time has been increased by more than two orders of magnitude. In addition, there have been major efforts to investigate the relevant ionization, electron removal, and energy transfer processes in such air plasmas, to model and analyze both e-beam and short pulse ionization sources in large volume air plasmas, to develop short pulse ionization wave generators, and to develop and employ advanced diagnostic methods to characterize the air plasmas produced. There have been major positive and novel results achieved in each of these areas.

Download or read book Aeronautics and Astronautics written by Max Mulder and published by BoD – Books on Demand. This book was released on 2011-09-12 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: In its first centennial, aerospace has matured from a pioneering activity to an indispensable enabler of our daily life activities. In the next twenty to thirty years, aerospace will face a tremendous challenge - the development of flying objects that do not depend on fossil fuels. The twenty-three chapters in this book capture some of the new technologies and methods that are currently being developed to enable sustainable air transport and space flight. It clearly illustrates the multi-disciplinary character of aerospace engineering, and the fact that the challenges of air transportation and space missions continue to call for the most innovative solutions and daring concepts.