Effects of DME mixing on number density and size properties of soot particles in counterflow non-premixed ethylene flames
Effects of DME mixing on number density and size properties of soot particles in counterflow non-premixed ethylene flames
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DOI：
10.1007/s12206-015-0447-9
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发表时间：
2015-05
影响因子：
1.6
通讯作者：
Jong-Woong Choi;Byung Chul Choi;S. M. Lee;Suk Ho Chung;K. Jung;W. Jeong;Sang-Kyu Choi;Sung-Cheol Park
中科院分区：
文献类型：
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作者：
Jong-Woong Choi;Byung Chul Choi;S. M. Lee;Suk Ho Chung;K. Jung;W. Jeong;Sang-Kyu Choi;Sung-Cheol Park
为了研究二甲醚（DME）掺混对碳烟颗粒数密度和尺寸的影响，将DME以5%、14%和30%的掺混比掺混到逆流式非预混乙烯火焰中。激光消光/散射技术已被采用来测量的体积分数，数密度，和平均尺寸的烟尘颗粒。实验结果表明，最高的碳烟浓度观察到的火焰与混合比为5%和14%，然而，为30%的混合比的碳烟浓度下降。数值结果表明，在5%和14%的DME混合物中，炔丙基自由基（C3 H3）的浓度高于乙烯基火焰中的浓度，苯（C6 H6）的生成量也有所增加.这表明炔丙基在苯环形成中的关键作用。除了A1- + H2→ A1 + H（-R554）和n-C4 H5 + C2 H2 → A1 + H（R542）外，这些反应一般随着DME混合的增加而变得更强。因此，表明添加DME到乙烯火焰促进苯环的形成。注意，虽然最大C6 H6浓度在30%DME混合火焰中最大，但碳烟体积分数小于5%和14%混合比的碳烟体积分数。这是因为在发生碳烟生长的燃料侧的相对低温区域中，局部C6 H6浓度降低。
In order to investigate the effect of DME mixing on the number density and size of soot particles, DME was mixed in a counter flow non-premixed ethylene flame with mixture ratios of 5%, 14% and 30%. A laser extinction/scattering technique has been adopted to measure the volume fraction, number density, and mean size of soot particles. The experimental results showed that the highest soot concentrations were observed for flames with mixture ratios of 5% and 14%; however, for a mixture ratio of 30% the soot concentration decreased. Numerical results showed that the concentrations of propargyl radicals (C3H3) at the 5% and 14% ratios were higher than those measured in the ethylene-based flame, and the production of benzene (C6H6) in the 5% and 14% DME mixture flames was also increased. This indicates the crucial role of propargyl in benzene ring formation. These reactions generally become stronger with increased DME mixing, except for A1- + H2→ A1 + H (-R554) andn-C4H5+ C2H2→ A1 + H (R542). Therefore, it is indicated that adding DME to ethylene flames promotes benzene ring formation. Note that although the maximum C6H6concentration is largest in the 30% DME mixing flame, the soot volume fraction is smaller than those for the 5% and 14% mixture ratios. This is because the local C6H6concentration decreases in the relatively low temperature region in the fuel side where soot growth occurs.