Study on oscillatory extinction dynamics mechanism of dimethyl ether spherical diffusion flame

被引：0

作者：

Kang Y. ^{[1
]}

Zhang Y. ^{[1
]}

Zhang P. ^{[2
]}

Lu X. ^{[1
]}

机构：

[1] Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, Chongqing University, Chongqing

[2] School of Civil Engineering, Chongqing University, Chongqing

来源：

Huagong Xuebao/CIESC Journal | 2020年 / 71卷 / 04期

关键词：

Chemical reaction; Computational fluid dynamics; Fluid mechanics; Fuel; Reaction kinetics;

D O I：

10.11949/0438-1157.20190808

中图分类号：

学科分类号：

摘要：

The oscillatory extinction mechanism of micro-gravitational dimethyl ether (DME) spherical diffusion flame in hot- and cool-flame conditions was studied by numerical modeling with detailed chemistry and transport model. The results show that a stable self-sustaining cold flame can be established under microgravity conditions, and the cold flame reaction can significantly expand the flammability limit of flameout. Oscillation existed prior to the steady-state extinction turning point of either hot or cool flame. The oscillatory extinction of DME hot flame was governed by a single oscillatory mode, and its frequency (1 Hz or so) was independent of the ambient oxygen mole fraction. By contrast, the cool-flame oscillatory extinction was governed by dual mode of oscillation with distinct frequencies, and the oscillation period of the high-frequency mode significantly increased when approaching the extinction limit. Moreover, the dual oscillatory modes showed strong coupling interaction, so the cool-flame extinction was more complicated than hot flames. The sensitivity analysis indicated that the hot flame extinction was controlled by the competition reactions of high-temperature exothermicity/endothermicity and chain-branching/termination involving small molecules, and the cool flame extinction was controlled by competition of low-temperature branching and termination reactions in the negative temperature coefficient regime. © All Right Reserved.

引用

页码：1469 / 1481

页数：12

共 32 条

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