Numerical study of the effects of gravity on soot formation in laminar coflow methane/air diffusion flames under different air stream velocities | |
Kong, Wenjun2; Liu, Fengshan1 | |
刊名 | COMBUSTION THEORY AND MODELLING |
2009 | |
卷号 | 13期号:6页码:993-1023 |
关键词 | soot formation laminar diffusion flame microgravity combustion thermal radiation coflow air velocity |
英文摘要 | Numerical simulations of laminar coflow methane/air diffusion flames at atmospheric pressure and different gravity levels were conducted to gain a better understanding of the effects of gravity on soot formation by using relatively detailed gas-phase chemistry and complex thermal and transport properties coupled with a semi-empirical two-equation soot model. Thermal radiation was calculated using the discrete-ordinates method coupled with a non-grey model for the radiative properties of CO, CO(2), H(2)O, and soot. Calculations were conducted for three coflow air velocities of 77.6, 30, and 5 cm/s to investigate how the coflowing air velocity affects the flame structure and soot formation at different levels of gravity. The coflow air velocity has a rather significant effect on the streamwise velocity and the fluid parcel residence time, especially at reduced gravity levels. The flame height and the visible flame height in general increase with decreasing the gravity level. The peak flame temperature decreases with decreasing either the coflow air stream velocity or the gravity level. The peak soot volume fraction of the flame at microgravity can either be greater or less than that of its normal gravity counterpart, depending on the coflow air velocity. At sufficiently high coflowair velocity, the peak soot volume fraction increases with decreasing the gravity level. When the coflow air velocity is low enough, soot formation is greatly suppressed at microgravity and extinguishment occurs in the upper portion of the flame with soot emission from the tip of the flame owing to incomplete oxidation. The numerical results provide further insights into the intimate coupling between flame size, residence time, thermal radiation, and soot formation at reduced gravity level. The importance of thermal radiation heat transfer and coflow air velocity to the flame structure and soot formation at microgravity is demonstrated for the first time. |
WOS标题词 | Science & Technology ; Physical Sciences ; Technology |
类目[WOS] | Thermodynamics ; Energy & Fuels ; Engineering, Chemical ; Mathematics, Interdisciplinary Applications |
研究领域[WOS] | Thermodynamics ; Energy & Fuels ; Engineering ; Mathematics |
关键词[WOS] | NONPREMIXED FLAMES ; MICROGRAVITY ; GAS ; MODEL ; TEMPERATURE ; PREDICTION ; RADIATION ; BEHAVIOR ; BUOYANT ; SIZES |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000285461200004 |
内容类型 | 期刊论文 |
源URL | [http://ir.etp.ac.cn/handle/311046/106386] |
专题 | 工程热物理研究所_中国科学院工程热物理所(论文库)_期刊论文(SCI) |
作者单位 | 1.Natl Res Council Canada, Inst Chem Proc & Environm Tech, Ottawa, ON, Canada 2.Chinese Acad Sci, Inst Engn Thermophys, Beijing, Peoples R China |
推荐引用方式 GB/T 7714 | Kong, Wenjun,Liu, Fengshan. Numerical study of the effects of gravity on soot formation in laminar coflow methane/air diffusion flames under different air stream velocities[J]. COMBUSTION THEORY AND MODELLING,2009,13(6):993-1023. |
APA | Kong, Wenjun,&Liu, Fengshan.(2009).Numerical study of the effects of gravity on soot formation in laminar coflow methane/air diffusion flames under different air stream velocities.COMBUSTION THEORY AND MODELLING,13(6),993-1023. |
MLA | Kong, Wenjun,et al."Numerical study of the effects of gravity on soot formation in laminar coflow methane/air diffusion flames under different air stream velocities".COMBUSTION THEORY AND MODELLING 13.6(2009):993-1023. |
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