Measurement of Laminar Burning Speeds and Investigation of Flame Stability of Acetylene (C2H2)/Air Mixtures
01 Jan 2015-Journal of Energy Resources Technology-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 137, Iss: 1, pp 012204
TL;DR: In this article, a shadowgraph system equipped with a high speed CMOS camera was used to study flame structures and transition from smooth to cellular flames during flame propagation, and burning speeds were measured using a thermodynamic model employing the dynamic pressure rise during the flame propagation.
Abstract: Laminar burning speeds and flame structures of spherically expanding flames of mixtures of acetylene (C2H2) with air have been investigated over a wide range of equivalence ratios, temperatures, and pressures. Experiments have been conducted in a constant volume cylindrical vessel with two large end windows. The vessel was installed in a shadowgraph system equipped with a high speed CMOS camera, capable of taking pictures up to 40,000 frames per second. Shadowgraphy was used to study flame structures and transition from smooth to cellular flames during flame propagation. Pressure measurements have been done using a pressure transducer during the combustion process. Laminar burning speeds were measured using a thermodynamic model employing the dynamic pressure rise during the flame propagation. Burning speeds were measured for temperature range of 300–590 K and pressure range of 0.5–3.3 atm, and the range of equivalence ratios covered from 0.6 to 2. The measured values of burning speeds compared well with existing data and extended for a wider range of temperatures. Burning speed measurements have only been reported for smooth and laminar flames. [DOI: 10.1115/1.4028363]
Citations
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Abstract: A detailed chemical kinetic model for oxidation of acetylene at intermediate temperatures and high pressure has been developed and evaluated experimentally. The rate coefficients for the reactions of C2H2 with HO2 and O2 were investigated, based on the recent analysis of the potential energy diagram for C2H3 + O2 by Goldsmith et al. and on new ab initio calculations, respectively. The C2H2 + HO2 reaction involves nine pressure- and temperature-dependent product channels, with formation of triplet CHCHO being dominant under most conditions. The barrier to reaction for C2H2 + O2 was found to be more than 50 kcal mol−1 and predictions of the initiation temperature were not sensitive to this reaction. Experiments were conducted with C2H2/O2 mixtures highly diluted in N2 in a high-pressure flow reactor at 600–900 K and 60 bar, varying the reaction stoichiometry from very lean to fuel-rich conditions. Model predictions were generally in satisfactory agreement with the experimental data. Under the investigated conditions, the oxidation pathways for C2H2 are more complex than those prevailing at higher temperatures and lower pressures. Acetylene is mostly consumed by recombination with H to form vinyl (reducing conditions) or with OH to form a CHCHOH adduct (stoichiometric to lean conditions). Both C2H3 and CHCHOH then react primarily with O2. The CHCHOH + O2 reaction leads to formation of significant amounts of glyoxal (OCHCHO) and formic acid (HOCHO), and the oxidation chemistry of these intermediates is important for the overall reaction.
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References
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TL;DR: In this paper, the effect of adding simulated combustion products to stoichiometric isooctane-air mixtures was also studied for diluent mass fractions f = 0−0.2.
871 citations
"Measurement of Laminar Burning Spee..." refers methods in this paper
...A detailed description of the model is demonstrated in previous publications [15–27]....
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TL;DR: In this paper, the laminar burning velocity of propane-air mixtures has been measured in the pressure range 0.4 to 40 atm and temperature range 298 to 750 K for equivalence ratios from 0.8 to 1.5.
511 citations
"Measurement of Laminar Burning Spee..." refers methods in this paper
...This model was developed by Metghalchi and Keck [14] and was modified to account for the energy losses to electrode and vessel wall and radiation from the burned gas to the wall as well as the temperature gradient in the preheat zone....
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01 Feb 1974
TL;DR: In this paper, a model for describing turbulent flame propagation in internal combustion engines is presented, and an approximate analytic method for determining the equilibrium state of the burned gases is also presented.
Abstract: A model for describing turbulent flame propagation in internal combustion engines is presented. An approximate analytic method for determining the equilibrium state of the burned gases is also presented. To verify the predictions of the model, experiments were carried out in a single-cylinder research engine at speeds from 1000-3200 rpm, spark advances from 30-110 deg btc and fuel-air equivalence ratios from 0.7-1.5. Simultaneous measurements of the cylinder pressure and the position of the flame front as a function of crank angle were made, and good agreement with the predictions of the model was obtained for all operating conditions.
407 citations
"Measurement of Laminar Burning Spee..." refers background in this paper
...Among these are ignition delay [4], effect of wall quenching layers [5], and minimum ignition energy [6]....
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01 Jan 2012
TL;DR: In this paper, an experimental system was designed to stabilize steady counterflow methane diffusion flames at elevated pressures, up to 3 MPa, and the replacement of nitrogen with helium as inert was found to be critical to stabilize well behaved flames with respect to steadiness, laminarity, adiabaticity, one dimensionality and flame thickness.
Abstract: An experimental system was designed to stabilize steady counterflow methane diffusion flames at elevated pressures, up to 3 MPa. In contrast with the much more common coflow configuration, the counterflow one is advantageous for the following reasons: the suppression of buoyancy instabilities that typically plague coflow flames at high pressures; the one-dimensionality of the flame, that enables computational modeling with very large chemical kinetic mechanisms; and the high level of control that it provides on soot loading. Above 0.8 MPa, the replacement of nitrogen with helium as inert was found to be critical to stabilize well behaved flames with respect to steadiness, laminarity, adiabaticity, one-dimensionality and flame thickness. Scaling and experimental considerations allowed for the identification of acceptable operating conditions in terms of pressure and strain rate and yielded a synthetic representation of a domain of diffusion flames of good quality. Such a graph can inform the design of a high-pressure counterflow system with respect to the selection of burner geometry, diagnostic techniques and experimental conditions, allowing for the experimentalist to sidestep costly and time consuming trial and error. Measurements by thin-filament pyrometry and numerical simulations confirmed the proposed scaling.
246 citations
"Measurement of Laminar Burning Spee..." refers methods in this paper
...[6] measured laminar burning speeds in stoichiometric hydrogen and hydrogenhydrocarbon gas mixtures using constant volume method....
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