Research on the relation of flame front curvature and oscillatory flame propagation by external laser irradiation method
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- 作者：Masakazu Tsuchimoto ; Osamu Fujita ; Teruaki Honko ; Yuji Nakamura ; Hiroyuki Ito
- 关键词：Premixed flame ; Instability ; Flame structure ; Lewis number effect
- 刊名：Proceedings of the Combustion Institute
- 出版年：2009
- 出版时间：2009
- 年：2009
- 卷：32
- 期：1
- 页码：1003-1009
- 全文大小：1001 K
文摘
Oscillatory propagation phenomena of ethylene premixed gas induced by absorption of externally supplied CO2 laser was investigated. Premixed gas was filled in a combustion tube of 50 mm in diameter at 0.1 MPa and CO2 laser beam of different diameter was irradiated along the center axis of the tube. The experimental results showed that the flame front curvature was controlled by the irradiated beam diameter and had strong effect on the oscillatory propagation behavior. When the beam diameter is narrow, the flame oscillation phenomena clearly appeared and the oscillation frequency became larger with increased flame front curvature. On the other hand, oscillation phenomena could not be observed when beam diameter was lager than a certain value. According to the time-resolved observation, it was found that the flame front curvature fluctuated with time when oscillatory propagation appeared and the instant of the maximum curvature presence corresponded to the instant of flame propagation deceleration or pause. The observed results could support the mechanism of the oscillation propagation proposed in the previous study, which included the relation of the flame front curvature and thermal-diffusive instability.