Visualization study of ignition modes behind bifurcated-reflected shock waves

Yamashita, Hideaki; Kasahara, Jiro; Sugiyama, Yoshinobu; Matsuo, Akiko

doi:10.1016/j.combustflame.2012.05.009

Cited by 50 publications

(20 citation statements)

References 27 publications

(45 reference statements)

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“…Lamnaouer et al also showed the presence of local hotspots in the wall jet after the passage of the bifurcation. Further simulations, such as those from Yamashita et al, 35 give evidence for hotspots in bifurcated flows. Combined with experimental schlieren results that indicate early ignition due to hotspots near the shock-tube walls, the numerical results of Yamashita et al 35 and Lamnaouer et al 31 give depth of understanding in determining the mechanism for this autoignition behavior.…”

Section: Experimental Nonidealitiesmentioning

confidence: 93%

Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation

Hargis

Petersen

2015

Energy Fuels

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Experiments were performed in a shock-tube facility to examine experimentally the kinetic effect, if any, of excess amounts of CO 2 as part of natural-gas-based fuel−oxidizer mixtures. An important aspect of these experiments was to also observe the role excess amounts of CO 2 play in causing nonidealities, particularly shock bifurcation, in shock-tube experiments using real (nondilute) fuel−air mixtures. Mixtures were composed of methane fuel at an equivalence ratio of 0.5 to represent a typical natural gas in a modified "air" mixture designed to study the effect of large levels of CO 2 dilution. These oxidizer compositions maintained constant levels of O 2 while exchanging N 2 for CO 2 in stages to give oxidizer mixture concentrations ranging from (0.21O 2 + 0.79N 2 ) to (0.21O 2 + 0.79CO 2 ). Low-pressure and high-pressure (near 1 and 10 atm, respectively) experiments were conducted over an approximate temperature range of 1450 to 1900 K. Results showed that the observed effect of CO 2 relating to reflected-shock bifurcation was quite significant, giving stronger bifurcation as amounts of CO 2 increased, as determined by a sidewall pressure transducer. Despite the presence of significant reflected-shock bifurcation in the mixtures containing high levels of CO 2 , the resulting ignition delay times were commensurate with the results expected if one were to assume the test conditions were at the inferred temperature and pressure immediately behind the reflected shock wave. That is, the main ignition events occurred in the gas closest to the endwall, where the effects of the shock bifurcation were minimal for the ignition delay time range of the present study. When the ignition delay times for mixtures with and without CO 2 dilution were compared, the effect of the CO 2 was minimal and within the uncertainty of the data, particularly for the experiments near 1 atm. A small effect of CO 2 addition was seen for the higher pressure near 10 atm, with a general increase in ignition delay time for the largest levels of CO 2 dilution. Predictions from a modern chemical kinetics model also showed a minimal effect of CO 2 addition on the methane ignition delay times, in agreement with the shock-tube data.

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Section: Experimental Nonidealitiesmentioning

confidence: 93%

Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation

Hargis

Petersen

2015

Energy Fuels

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“…The authors analyzed experiments by Meyer and Oppenheim (1971a), Yamashita et al (2012), Penyazkov et al (2005) and their own simulations and found transition from weak to strong ignition in the shock bifurcation regime at Da bif ≈ 1 . In contrast to the previously introduced models, this approach does not involve chemical sensitivity parameters.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 97%

“…The authors found that this criterion reproduced experimental data at low pressure more accurately than the extended second explosion limit. Yamashita et al (2012) studied ignition modes in stoichiometric C 2 H 2 /O 2 at 56 kPa < p 5 < 203 kPa. The criterion by Meyer 85 and Oppenheim seemed to be applicable for C 2 H 2 /O 2 .…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Models for shock-induced ignition evaluated by detailed chemical kinetics for hydrogen/air in the context of deflagration-to-detonation transition

Boeck

Mével

Sattelmayer

2017

Journal of Loss Prevention in the Process Industries

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“…However, if solid boundaries are present, the reflection of a shock wave generates high temperature and pressure in which local auto-ignition, and possibly DDT can occur [38]. For example, a shock which reflects off an obstacle, or end-wall, will propagate backwards into the region of pre-heated, unburned gas between the lead shock and trailing deflagration [39].…”

Section: Detonation Initiation By Shock Reflectionmentioning

confidence: 99%

Visualization of detonation propagation in a round tube equipped with repeating orifice plates

Rainsford

Aulakh

Ciccarelli

2018

Combustion and Flame

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This study used self-luminous high-speed photography to visualize quasi-detonation propagation and deflagration-to-detonation transition (DDT) in a transparent round tube equipped with repeating orifice plates. Experiments were conducted in a combustion channel consisting of a 3.16 m square channel with a 7.6 cm by 7.6 cm cross-section connected to a 1.55 m cylindrical channel filled with orifice plates. Rectangular 'fence-type' obstacles were installed on the top and bottom of the square channel with a 3.8 cm opening between them. Two sets of orifice plates with different diameters, d, representing different blockage ratios (BR) were tested (d=5.33 cm for 50% BR and 3.81 cm for 75% BR orifice plates). Stoichiometric hydrogen-oxygen mixtures at initial pressures of 4-60 kPa were ignited at one end of the combustion channel. Average propagation velocities were derived from shock-time-of-arrival measurements using pressure transducers in the square channel and high-speed video filmed through the round tube. First and foremost, I'd like to thank my supervisor, Dr. Gaby Ciccarelli, for his guidance, support and teaching over the past two years. This degree has been a wonderful opportunity and it has been a real pleasure to work on this project with him.

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Visualization study of ignition modes behind bifurcated-reflected shock waves

Cited by 50 publications

References 27 publications

Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation

Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation

Models for shock-induced ignition evaluated by detailed chemical kinetics for hydrogen/air in the context of deflagration-to-detonation transition

Visualization of detonation propagation in a round tube equipped with repeating orifice plates

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Visualization study of ignition modes behind bifurcated-reflected shock waves

Cited by 50 publications

References 27 publications

Methane Ignition in a Shock Tube with High Levels of CO2 Dilution: Consideration of the Reflected-Shock Bifurcation

Methane Ignition in a Shock Tube with High Levels of CO2 Dilution: Consideration of the Reflected-Shock Bifurcation

Models for shock-induced ignition evaluated by detailed chemical kinetics for hydrogen/air in the context of deflagration-to-detonation transition

Visualization of detonation propagation in a round tube equipped with repeating orifice plates

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Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation

Methane Ignition in a Shock Tube with High Levels of CO₂ Dilution: Consideration of the Reflected-Shock Bifurcation