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Dynamics and burning limits of near-limit hot, warm, and cool diffusion flames of dimethyl ether at elevated pressures

Published on Jan 1, 2019
· DOI :10.1016/j.proci.2018.05.082
Eric Lin1
Estimated H-index: 1
(Princeton University),
Christopher B. Reuter8
Estimated H-index: 8
(Princeton University),
Yiguang Ju57
Estimated H-index: 57
(Princeton University)
Abstract
Abstract The near-limit diffusion flame regimes and extinction limits of dimethyl ether at elevated pressures and temperatures are examined numerically in the counterflow geometry with and without radiation at different oxygen concentrations. It is found that there are three different flame regimes—hot flame, warm flame, and cool flame—which exist, respectively, at high, intermediate, and low temperatures. Furthermore, they are governed by three distinct chain-branching reaction pathways. The results demonstrate that the warm flame has a double reaction zone structure and plays a critical role in the transition between cool and hot flames. It is also shown that the cool flame can be formed in several different ways: by either radiative extinction or stretch extinction of a hot flame or by stretch extinction of a warm flame. A warm flame can also be formed by radiative extinction of a hot flame or ignition of a cool flame. A general €-shaped flammability diagram showing the burning limits of all three flame regimes at different oxygen mole fractions is obtained. The results show that thermal radiation, reactant concentration, temperature, and pressure all have significant impacts on the flammable regions of the three flame regimes. Increases in oxidizer temperature, oxygen concentration, and pressure shift the cool flame regime to higher stretch rates and cause the warm flame to have two extinction limits. At elevated temperatures, it is found that there is a direct transition between the hot flame and warm flame at low stretch rates. The results also show that, unlike the hot flame, the cool flame structure cannot be scaled by using pressure-weighted stretch rates due to the its significant reactant leakage and strong dependence of reactivity on pressure. The present results advance the understanding of near-limit flame dynamics and provide guidance for experimental observation of different flame regimes.
  • References (26)
  • Citations (1)
References26
Newest
#1Omar R. Yehia (Princeton University)H-Index: 2
#2Christopher B. Reuter (Princeton University)H-Index: 8
Last.Yiguang Ju (Princeton University)H-Index: 57
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#1Christopher B. Reuter (Princeton University)H-Index: 8
#2Minhyeok Lee (Princeton University)H-Index: 2
Last.Yiguang Ju (Princeton University)H-Index: 57
view all 4 authors...
#1Sili Deng (Princeton University)H-Index: 6
#2Dong Han (Princeton University)H-Index: 14
Last.Chung King Law (Princeton University)H-Index: 81
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#1Christopher B. Reuter (Princeton University)H-Index: 8
#2Sang Hee Won (Princeton University)H-Index: 30
Last.Yiguang Ju (Princeton University)H-Index: 57
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#2Hee Sun Han (Sejong University)H-Index: 1
Last.Sang Hee Won (Princeton University)H-Index: 30
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#1Tianhan Zhang (Princeton University)H-Index: 2
#2Weiqi Sun (Princeton University)H-Index: 6
Last.Yiguang Ju (Princeton University)H-Index: 57
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#1Yiguang Ju (Princeton University)H-Index: 57
#2Christopher B. Reuter (Princeton University)H-Index: 8
Last.Sang Hee Won (Princeton University)H-Index: 30
view all 3 authors...
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#2Michael C. Hicks (Glenn Research Center)H-Index: 8
Last.Frederick L. Dryer (Princeton University)H-Index: 68
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