High-speed Imaging of Reflected Shockwave-initiated Combustion

High-speed Imaging of Reflected Shockwave-initiated Combustion
Author: Erik Ninnemann
Publisher:
Total Pages: 48
Release: 2020
Genre:
ISBN:

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Shock tubes are considered ideal reactors and are used extensively to provide valuable chemical kinetic measurements, such as ignition delay times and in-situ species time-histories. However, due to nonideal affects the combustion of fuel inside shock tubes can become nonhomogeneous, particularly at low temperatures, which complicates the acquired data. In this work, the combustion of practical fuels used by society are investigated with high-speed imaging. First, high-speed images were captured through the end wall of the shock tube for two hydrogen-oxygen systems. The combustion process was found to initiate in two modes, one that is homogeneous across the fluid medium and one that proceeds through a deflagration to detonation channel. In the second part of this work, the shock tube test section was redesigned to promote optical access from the end and side walls of the shock tube test section. Two high-speed cameras were used to capture perpendicular views of the combustion of iso-octane and n-heptane, two primary reference fuels. A homogeneous and nonhomogeneous combustion process were seen for these fuels as well. Using the side view images, the impact of the sporadic ignition process was evaluated on commonly used diagnostics in shock tubes. Based on these results, it is recommended that shock tube diagnostics be confined to the homogeneous ignition modes of fuels. This is found to strongly correlate with the temperature of the combustion process, where high temperatures promote a homogeneous ignition event.

Thermo-Gas Dynamics of Hydrogen Combustion and Explosion

Thermo-Gas Dynamics of Hydrogen Combustion and Explosion
Author: Boris E. Gelfand
Publisher: Springer Science & Business Media
Total Pages: 338
Release: 2012-02-09
Genre: Science
ISBN: 3642253520

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The potential of hydrogen as an important future energy source has generated fresh interest in the study of hydrogenous gas mixtures. Indeed, both its high caloricity and reactivity are unique properties, the latter underscoring safety considerations when handling such mixtures. The present monograph is devoted to the various aspects of hydrogen combustion and explosion processes. In addition to theoretical and phenomenological considerations, this work also collates the results of many experiments from less well known sources. The text reviews the literature in this respect, thereby providing valuable information about the thermo-gas-dynamical parameters of combustion processes for selected experimental settings in a range of scientific and industrial applications.

Ninth Symposium (International) on Combustion

Ninth Symposium (International) on Combustion
Author: Sam Stuart
Publisher: Elsevier
Total Pages: 1118
Release: 2013-09-11
Genre: Science
ISBN: 1483261573

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Ninth Symposium (International) on Combustion covers the proceedings of the Ninth Symposium (International) on Combustion, held at Cornell University in Ithaca, New York on August 27 to September 1, 1962, under the auspices of the Combustion Institute. The book focuses on the processes and reactions involved in combustion. The selection first offers information on flame strength of propane-oxygen flames at low pressures in turbulent flow and mixing and flow in ducted turbulent jets. Topics include radial profile of the jetting velocity, radial growth of the jet, and mixing zones of a ducted jet. The text then elaborates on turbulent flame studies in two-dimensional open burners; turbulent mass transfer and rates of combustion in confined turbulent flames; and flame stabilization in a boundary layer. The publication examines the theoretical study of properties of laminar steady state flames as a function of properties of their chemical components and spectra of alkali metal-organic halide flames. The text then takes a look at the thermal radiation theory for plane flame propagation in coal dust clouds; flame characteristics of the diborane-hydrazine system; and studies of the combustion of dimethyl hydrazine and related compounds. The selection is a dependable reference for readers interested in the processes and reactions involved in combustion.

Detonation Control for Propulsion

Detonation Control for Propulsion
Author: Jiun-Ming Li
Publisher: Springer
Total Pages: 246
Release: 2017-12-05
Genre: Technology & Engineering
ISBN: 3319689061

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This book focuses on the latest developments in detonation engines for aerospace propulsion, with a focus on the rotating detonation engine (RDE). State-of-the-art research contributions are collected from international leading researchers devoted to the pursuit of controllable detonations for practical detonation propulsion. A system-level design of novel detonation engines, performance analysis, and advanced experimental and numerical methods are covered. In addition, the world’s first successful sled demonstration of a rocket rotating detonation engine system and innovations in the development of a kilohertz pulse detonation engine (PDE) system are reported. Readers will obtain, in a straightforward manner, an understanding of the RDE & PDE design, operation and testing approaches, and further specific integration schemes for diverse applications such as rockets for space propulsion and turbojet/ramjet engines for air-breathing propulsion. Detonation Control for Propulsion: Pulse Detonation and Rotating Detonation Engines provides, with its comprehensive coverage from fundamental detonation science to practical research engineering techniques, a wealth of information for scientists in the field of combustion and propulsion. The volume can also serve as a reference text for faculty and graduate students and interested in shock waves, combustion and propulsion.

Investigation of Oxy-fuel Combustion Behind Reflected Shock Waves

Investigation of Oxy-fuel Combustion Behind Reflected Shock Waves
Author: Owen Marcus Pryor
Publisher:
Total Pages: 109
Release: 2018
Genre:
ISBN:

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Supercritical carbon dioxide has brought about new questions on the chemical kinetics of several small hydrocarbon fuels and the effects of carbon dioxide as the primary diluent on the different fuels. This report presents work on the ignition delay times and several species time-histories of methane, ethylene and syngas over a range of conditions. All experiments were conducted behind reflected shock waves using two different shock tubes. The ignition delay times were measured using a GaP photodetector to measure the emission of light. The species time-histories were measured using single laser spectroscopy. The effect of CO2 as a diluent on the fluid dynamics of the system were also examined using high-speed camera images. It was determined that the ignition delay times and fuel time-histories were able to be accurately predicted by mechanisms in the literature for pressures up to 30 atm but the literature mechanisms were unable to predict the carbon monoxide time-histories beyond qualitative trends for the various fuels. It was also determined that the carbon monoxide had a string effect on the fluid dynamics of the experiments resulting in a significantly smaller chemical reaction zone. Experiments were also performed to examine the effects of water as a diluent with a ratio up to 66% of the total diluent on the ignition delay times. Using the experimental data, a global kinetic mechanism was created for methane and syngas to predict the ignition delay times and the carbon monoxide time-histories for pressures up to 300 atm.

Explosion Shock Waves and High Strain Rate Phenomena

Explosion Shock Waves and High Strain Rate Phenomena
Author: K. Hokamoto
Publisher: Materials Research Forum LLC
Total Pages: 182
Release: 2019-08-20
Genre: Technology & Engineering
ISBN: 1644900335

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The book presents the papers presented at the 6th international conference on Explosion, Shock Wave and High Strain-Rate Phenomena (ESHP). Topics covered include: Advanced Manufacturing under Impact/Shock Loading, Detonation of High Pressure Flammable Gas in Closed Spaces, High Strain-Rate Behaviour of Auxetic Cellular Structures, Underwater Shock Waves Generation, Magnetic Pressure Welding of Aluminum Sheets, Shock Synthesis of Zirconium Oxides, Impact Joining of Dissimilar Metals, High-Speed Oblique Collision of Metals, Dynamic Behavior of Dislocation Wall Structures, Tensile Strength of Rock at High Strain Rates, Fiber Reinforced Mortar, Impact Analysis of Carbon Fiber Reinforced Polymer, Explosive Welding , Underwater Explosive Welding , Making Ultrafine Explosives, Aluminum-Steel Explosive Cladding, Explosively Cladded Aluminum Hybrid Composites, Explosive Clads with Interlayers.

Numerical Modeling of Shockwave Initiated Combustion of a Hydrogen-oxygen Mixture Within a Shock Tube

Numerical Modeling of Shockwave Initiated Combustion of a Hydrogen-oxygen Mixture Within a Shock Tube
Author: Reed W. Forehand
Publisher:
Total Pages: 56
Release: 2021
Genre:
ISBN:

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Shock tubes are as close to an ideal reactor as most modern experiments can attain to examine chemical kinetics. As reaction temperatures drop, homogeneous combustion within a shock tube begins to exhibit inhomogeneous modes, which in a typical Hydrogen-Oxygen system are expressed as deflagration to detonation transition. Experimental results of such a system in the University of Central Florida’s low-pressure shock tube have been collected through end and side-wall imaging to analyze flame structure and chemical kinetics. The purpose of this work is to conduct a baselining of these results using both chemical and computational fluid dynamics modeling. The model will use the Siemens STAR-CCM+ computational fluid dynamics software in order to accurately simulate the system. A seven-step reaction mechanism will be used to accurately capture initialization, propagation, and termination of the combustion within an implicit unsteady, three-dimensional, direct eddy simulation solution on a well-conditioned mesh. The end goal of this study is to create a lightweight model of hydrogen-oxygen combustion with a shock tube for baselining purposes. Both a two- and three- dimensional model were applied in this effort. The simulation results indicate good conditioning and agreement with the experimental results, although some combustion phenomena are not captured as well as a higher fidelity, significantly more computationally expensive model would.

Proceedings

Proceedings
Author:
Publisher:
Total Pages: 688
Release: 1967
Genre: Acoustic phenomena in nature
ISBN:

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