Effects of the Karlovitz number on the evolution of the flame surface density in turbulent premixed flames

被引:35
|
作者
Han, Insuk [1 ]
Huh, Kang Y. [1 ]
机构
[1] Pohang Univ Sci & Technol, Div Mech Engn, San 31 Hyojadong, Pohang 790784, Kyungbuk, South Korea
关键词
Turbulent premixed flame; Direct numerical simulation; Flame surface density; Displacement speed; Karlovitz number; REACTION-ZONES REGIME; LARGE-EDDY SIMULATION; STRAIN-RATE; COMBUSTION; CURVATURE; PROPAGATION; EQUATION; SCHEMES; STRETCH;
D O I
10.1016/j.proci.2008.07.041
中图分类号
O414.1 [热力学];
学科分类号
摘要
Direct numerical simulation (DNS) is conducted to investigate the effects of the Karlovitz number (Ka) on displacement speed and consequent evolution of flame surface density (FSD). Parametric study is performed for the Ka between 2 and 10 in the thin reaction zone regime with independent variation of laminar flame speed and turbulent intensity. Previous study showed the effect of the turbulent intensity without noticeable influence of the Ka lower than 2.4 [I. Han, K.Y. Huh, Combust. Flame 152 (2008) 194-205]. A higher Ka involves a lower displacement speed on the positive curvature side primarily due to the influence on the normal diffusion component. It leads to a negative curvature term to act as a sink for FSD throughout a flame brush. The maximum FSD increases with increasing turbulent intensity, while a higher Ka leads to an asymmetric profile of FSD due to suppressed production at the leading edge. A higher Ka decreases total flame area and turbulent burning velocity as well, while a limiting behavior is shown for low Da cases. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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页码:1419 / 1425
页数:7
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