대한기계학회:학술대회논문집 (Proceedings of the KSME Conference)
- 대한기계학회 2000년도 춘계학술대회논문집B
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- Pages.422-427
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- 2000
대향류 유동장에서 삼지 화염 전파 특성에 관한 연구
Characteristics of Propagating Tribrachial Flames in Counterflow
- 발행 : 2000.04.20
초록
Propagation characteristics of tribrachial flames have been investigated experimentally in both two-dimensional and axisymmetric counterflows. Mixture fraction gradient at stoichiometric location is controlled by varying equivalence ratios at the two nozzles, one of which maintains rich while the other lean premixture. Tribrachial flames propagating through these mixtures are investigated. The propagation speed of tribrachial flames in two-dimensional counterflow decreases with fuel concentration gradient and has much higher speed than the maximum speed predicted previously in two-dimensional mixing layers. From an analogy with premixed flame propagation, this excessively large propagation speed can be attributed to the tribrachial flame propagating with respect to burnt gas. Corresponding maximum speed in the limit of small mixture fraction gradient is estimated and extrapolated experimental results substantiate this limiting speed. As mixture fraction gradient approaches zero, a transition in propagation characteristics occurs, such that the propagation speed of tribrachial flame approaches stoichiometric laminar burning velocity with respect to burnt gas. Similar behavior has been obtained for tribrachial flames propagating in axisymmetric counterflow.