著者

Yamashita Hiroki Kasahara Jiro Sugiyama Yuta Matsuo Akiko

出版者

Elsevier Inc.

雑誌

Combustion and flame (ISSN:00102180)

巻号頁・発行日

vol.159, no.9, pp.2954-2966, 2012-09

被引用文献数

47 1

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This study was a numerical and experimental investigation of low-temperature auto-ignitions behindreflected shock waves in which a shock tube was employed as the experimental system. We used ahigh-speed video camera and the Schlieren method to visualize the ignition phenomena. Experimentswere performed over a temperature range from 549 ± 10 to 1349 ± 11 K and a pressure range from56 ± 2 to 203 ± 13 kPa, and a non-diluted stoichiometric acetylene–oxygen mixture was chosen as thecombustible gas. We introduced a numerical simulation to help us understand the disturbed temperaturedistribution behind bifurcated shock waves due to interference between reflected shock waves and theboundary layer developed behind incident shock waves. Additionally, we experimentally observed andevaluated quantitatively a tendency for ignition positions to be located farther from the reflecting wallas the temperature decreased behind reflected shock waves. To focus our attention on the ignition positions,we classified the ignition types behind reflected shock waves as near-wall ignition and far-wallignition by 4.7 mm distance from reflecting wall. The criterion for these ignition types was estimatedto be -1.0≦(∂ti/∂T5t)p5t≦-0.5. As a main object in this manuscript, we proposed an ignition modelin which local ignition is induced at some distance from reflecting wall based on the numerical simulationand results; the local ignitions at a point distant from the reflecting wall are induced by the temperaturerise, with the distance from the reflecting wall, immediately behind concave reflected shock wavesdue to developing of bifurcated shock waves. We confirmed that there is no discrepancy between the proposedmodel and experimental results.