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Book Evaluation and Characterization Study of Dual Pulse Laser induced Spark DPLIS for Rocket Engine Ignition System Application

Download or read book Evaluation and Characterization Study of Dual Pulse Laser induced Spark DPLIS for Rocket Engine Ignition System Application written by Robin J. Osborne and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Aerospace America

Download or read book Aerospace America written by and published by . This book was released on 2003 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Dual pulse Laser induced Breakdown for Ignition Applications

Download or read book Dual pulse Laser induced Breakdown for Ignition Applications written by Lydia R. Wermer and published by . This book was released on 2019 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Laser Ignition of Internal Combustion Engines

Download or read book Laser Ignition of Internal Combustion Engines written by Martin Weinrotter and published by GRIN Verlag. This book was released on 2011-03-31 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2006 in the subject Electrotechnology, grade: 1, mit Ausgezeichnung bestanden, Vienna University of Technology (Insitut für Photonik), language: English, abstract: In this PhD thesis different fundamental aspects and the practical usability of a laser ignition system as a new, innovative and alternative ignition approach for internal combustion engines were investigated in great detail mainly experimentally. Ignition experiments in combustion chambers under high pressures and elevated temperatures have been conducted. Different fuels were investigated. Also the minimum breakdown energy in dependence of the initial temperature and pressure with the help of an aspheric lens with a high numerical aperture was studied. High-speed Schlieren diagnostics have been conducted in the combustion chamber. The different stages like the ignition plasma within the first nanoseconds via the shock wave generation to the expanding flame kernel were investigated. With the help of multi-point ignition the combustion duration could be reduced significantly. The controlled start of auto-ignition of n-heptane-air mixtures by resonant absorption of Er,Cr:YSGG laser radiation at 2.78 μm by additionally introduced water has been proven in combustion chamber experiments as a completely new idea. Beside experiments in the combustion chambers and long term tests under atmospheric conditions, various tests in SI engines up to 200 h, have been made. Different sources of contamination of the window surface have been identified. First experiments with a longitudinally diode-pumped, fiber-coupled and passively Q-switched solid-state laser α-prototype system with maximum pulse energy of 1.5 mJ at about 1.5 ns pulse duration were performed which allowed to ignite the engine successfully over a test period of 100 h. In cooperation with Lund University in Sweden, experiments have been performed on another engine test bed running in HCCI mode revealing the laser spark to be able to stimulate the auto-ignition process and to trigger the onset of combustion. In another international cooperation conducted with the Southwest Research Institute in Texas, U.S.A., the potential of laser ignition in combination with the so called HEDGE concept was studied. As a final direction of the work, first calculations and experiments of a β- prototype ignition laser of an own design have been conducted. The concept of a longitudinally diode-pumped, fiber-coupled and passively Q-switched solid-state laser was chosen as the most promising. Emitted pulse energy of 2 mJ within around 1 ns pulse duration was achieved easily allowing generating a laser-induced breakdown in air.

Book Effect of Spark Kernel Dynamics on Laser induced Minimun Ignition Energies of Combustible Gases

Download or read book Effect of Spark Kernel Dynamics on Laser induced Minimun Ignition Energies of Combustible Gases written by Elliot Hing-Gwok Lim and published by . This book was released on 1997 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lewis and von Elbe's data on minimun spark ignition energies in gases have been the standard for many years, howewer, these data still do not agree with the most detailed computational models available. Current models predict lower minimun ignition energy values. An experimental program was initiated to better characterize the ignition source and to study its effect on minimun ignition energies. The apparatus constits of a laser ignition source operating either as a Q-switched nanosecond or a pulsed mode-locked picosecond laser. For mixtures of varying equivalence ratio, the minimun ignition energy was bracketed through repeated trials at varying laser spark energies. The current study has shown that laser sparks of different pulse durations produce larger minimun ignition energies (MIEs) in comparison to electric discharge and that the MIE is a function of laser pulse duration. The laser ignition experiments are consistent with Lewis and von Elbe's measurements for lean and rich mixtures ; howewer, neared to stoichiometric mixtures, the laser ignition values are significantly higher. To better understand these differences, measurements of the spark size and dynamics of spark propagation were made using visible emission, schlieren and interferometric imaging. It is found that although the laser energy is deposited in a small volume (typically a nearly-spherical region of 0.3 mm radius), the thermal energy deposited by the spark expands to a size much larger than the calculated minimun flame kernel on a time scale much shorter than the time scale for ignition. This indicates that the energy remaining within the initial deposition region is only a small fraction of the total deposited energy. Consequently, the energy deposition process does not necessarily couple efficiently into the ignition process. The picosecond and nanosecond pulse duration sparks were also seen to exhibit different expansion properties, with the nanosecond source yielding (for the same energy deposition) larger kernels after completion of the expansion process. From these observations it is concluded that the minimun ignition energies are strongly influenced by the dynamics of spark propagation, which in turn vary for different energy sources. In particular, it appears unlikely that the short-duration laser ignition sources are capable of yielding minimun ignition energies as low as longer-duration electric spark sources.

Book Laser Pulse Phenomena and Applications

Download or read book Laser Pulse Phenomena and Applications written by F. J. Duarte and published by IntechOpen. This book was released on 2010-12-30 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed lasers are available in the gas, liquid, and the solid state. These lasers are also enormously versatile in their output characteristics yielding emission from very large energy pulses to very high peak-power pulses. Pulsed lasers are equally versatile in their spectral characteristics. This volume includes an impressive array of current research on pulsed laser phenomena and applications. Laser Pulse Phenomena and Applications covers a wide range of topics from laser powered orbital launchers, and laser rocket engines, to laser-matter interactions, detector and sensor laser technology, laser ablation, and biological applications.

Book Laser Ignition Application in a Space Experiment

Download or read book Laser Ignition Application in a Space Experiment written by and published by . This book was released on 1993 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Laser Induced Spark Ignition of Methane Oxygen Mixtures

Download or read book Laser Induced Spark Ignition of Methane Oxygen Mixtures written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-12-31 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results from an experimental study of laser induced spark ignition of methane-oxygen mixtures are presented. The experiments were conducted at atmospheric pressure and 296 K under laminar pre-mixed and turbulent-incompletely mixed conditions. A pulsed, frequency doubled Nd: YAG laser was used as the ignition source. Laser sparks with energies of 10 mJ and 40 mJ were used, as well as a conventional electrode spark with an effective energy of 6 mJ. Measurements were made of the flame kernel radius as a function of time using pulsed laser shadowgraphy. The initial size of the spark ignited flame kernel was found to correlate reasonably well with breakdown energy as predicted by the Taylor spherical blast wave model. The subsequent growth rate of the flame kernel was found to increase with time from a value less than to a value greater than the adiabatic, unstretched laminar growth rate. This behavior was attributed to the combined effects of flame stretch and an apparent wrinkling of the flame surface due to the extremely rapid acceleration of the flame. The very large laminar flame speed of methane-oxygen mixtures appears to be the dominant factor affecting the growth rate of spark ignited flame kernels, with the mode of ignition having a small effect. The effect of incomplete fuel-oxidizer mixing was found to have a significant effect on the growth rate, one which was greater than could simply be accounted for by the effect of local variations in the equivalence ratio on the local flame speed. Santavicca, D. A. and Ho, C. and Reilly, B. J. and Lee, T.-W. NASA-CR-188689, NAS 1.26:188689 NAG3-966...

Book Laser Spark Distribution and Ignition System

Download or read book Laser Spark Distribution and Ignition System written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

Book Laser Diagnostics and Optical Measurement Techniques in Internal Combustion Engines

Download or read book Laser Diagnostics and Optical Measurement Techniques in Internal Combustion Engines written by Hua Zhao and published by SAE International. This book was released on 2012-07-30 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing concern about CO2 emissions and energy prices has led to new CO2 emission and fuel economy legislation being introduced in world regions served by the automotive industry. In response, automotive manufacturers and Tier-1 suppliers are developing a new generation of internal combustion (IC) engines with ultra-low emissions and high fuel efficiency. To further this development, a better understanding is needed of the combustion and pollutant formation processes in IC engines. As efficiency and emission abatement processes have reached points of diminishing returns, there is more of a need to make measurements inside the combustion chamber, where the combustion and pollutant formation processes take place. However, there is currently no good overview of how to make these measurements. Based on the author’s previous SAE book, Engine Combustion Instrumentation and Diagnostics, this book focuses on laser-based optical techniques for combustion flows and in-cylinder measurements. Included are new chapters on optical engines and optical equipment, case studies, and an updated description of each technique. The purpose of this book is to provide, in one publication, an introduction to experimental techniques that are best suited for in-cylinder engine combustion measurements. It provides sufficient details for readers to set up and apply these techniques to IC engines and combustion flows.

Book Application of Laser Induced Fluorescence LIF to Liquid Propellant Rocket Engine Testing

Download or read book Application of Laser Induced Fluorescence LIF to Liquid Propellant Rocket Engine Testing written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion exhausts present a challenging problem for researchers due to the extremely harsh environment, and nonintrusive diagnostics are often sought to provide flow property information. Laser induced fluorescence (LIF) is one technique in which a chosen flow molecule or marker is probed to yield gross flow properties, such as static temperature and flow velocities. The work presented herein describes the application of LIF to the combustion exhausts of several full-scale liquid-propellant rocket engines spanning a wide range of operational parameters. The method is based upon the use of CW ring-dye lasers which scan in frequency over either the Na D1 or D2 line at 5896 and 5890 A. Na is used as a basis for this approach since it occurs as a trace element in both hydrogen and amine rocket fuels. The generic apparatus is described, including a discussion of the collection and interpretation of the LIF signal to yield radial and temporal profiles of radial flow velocity, static temperature, and fuel distribution. It was found that the LIF technique provides quality data in most cases. Certain stressing situations were also found in which data on the flow properties were not obtainable. Also, computational fluid dynamics (CFD) modeling of the plumes was used to provide baseline estimates of the exhaust flow properties. The model reasonably predicted the gross behavior of the flow as determined by the LIF technique, although some items of fine spatial structure were not reproduced very well.

Book A Laser Spark Plug Ignition System for a Stationary Lean Burn Natural Gas Reciprocating Engine

Download or read book A Laser Spark Plug Ignition System for a Stationary Lean Burn Natural Gas Reciprocating Engine written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet the ignition system needs of large bore, high pressure, lean burn, natural gas engines a side pumped, passively Q-switched, Nd:YAG laser was developed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn, high compression engine. The laser and associated optics were designed with a passive Q-switch to eliminate the need for high voltage signaling and associated equipment. The laser was diode pumped to eliminate the need for high voltage flash lamps which have poor pumping efficiency. The independent and dependent parameters of the laser were identified and explored in specific combinations that produced consistent robust sparks in laboratory air. Prior research has shown that increasing gas pressure lowers the breakdown threshold for laser initiated ignition. The laser has an overall geometry of 57x57x152 mm with an output beam diameter of approximately 3 mm. The experimentation used a wide range of optical and electrical input parameters that when combined produced ignition in laboratory air. The results show a strong dependence of the output parameters on the output coupler reflectivity, Q-switch initial transmission, and gain media dopant concentration. As these three parameters were lowered the output performance of the laser increased leading to larger more brilliant sparks. The results show peak power levels of up to 3MW and peak focal intensities of up to 560 GW/cm2. Engine testing was performed on a Ricardo Proteus single cylinder research engine. The goal of the engine testing was to show that the test laser performs identically to the commercially available flashlamp pumped actively Q-switched laser used in previous laser ignition testing. The engine testing consisted of a comparison of the in-cylinder, and emissions behavior of the engine using each of the lasers as an ignition system. All engine parameters were kept as constant as possilbe while the equivalence ratio (fueling), and hence the engine load, was varied between 0.8, 0.9, and 1.0. The test laser was constructed with a 30% output coupler, 32% Q-switch initial transmission, and a 0.5% Nd concentration rod all pumped by approximately 1000 Watts of optical power. The test laser single mode output pulse had an energy of approximately 23 mJ, with a pulsewidth of approximately 10 ns, and an M2 value of 6.55. This output produced focal intensity of approximately 270 GW/cm2 with the modified on-engine optical arrangement. The commercial laser had similar output parameters and both laser systems operated the engine with similar results. Due to the shortening of the focal length of the on-engine optical setup both laser systems produced a spark well within the optical transfer cavity of the laser optics to spark plug adaptor. This shrouded spark led to a very long ignition delay and retarded combustion timing for all three values of equivalence ratio. This was evidenced by the in-cylinder pressure traces and the HRR waveforms. The emissions data indicate that both lasers produced very similar combustion. The ignition delay caused by the shrouded spark cause most of the combustion to happen after TDC which lead to poor combustion that produced high levels of CO and THC. The novelty of this work lies in the combination of the laser parameters to create a single high peak power laser output pulse for use as a spark ignition source. Similar configurations have been investigated in the literature but for different applications such as multiple output pulse trains for various industrial and communications applications. Another point of novelty is the investigation of the laser medium concentration on the output characteristics of a passively Q-switched laser system. This work has shown that lowering the Neodymium concentration in the active media within a passively Q-switched laser produces higher output energy values. This is significant because an actively Q-switched laser shows the opposite affect when the active ion concentration is varied.