Large Eddy Simulation on the Flame Structure for Split Injections of n-dodecane at Different Temperatures and Densities
Large Eddy Simulation on the Flame Structure for Split Injections of n-dodecane at Different Temperatures and Densities
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不同温度和密度正十二烷分流喷射火焰结构的大涡模拟
DOI：
10.1080/00102202.2018.1498485
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发表时间：
2018-08
影响因子：
1.9
通讯作者：
Wei Haiqiao
中科院分区：
文献类型：
--
作者：
Zhou Lei;Zhao Wanhui;Wei Haiqiao
摘要采用大涡模拟与线性涡模型相结合的方法，对正十二烷多次喷射（0.5ms喷射/0.5ms停留/0.5ms喷射）喷雾火焰进行了数值模拟。通过将内工况下的蒸汽穿透长度和反应工况下的点火延迟时间预测值与实验结果进行比较，验证了模型的正确性。预测值与实测值吻合较好。分析了初始温度、环境气体密度等初始条件对双喷射发展的影响。通过降低环境气体密度或初始温度，高温核的出现被延迟。当初始气体密度在900 K的初始温度下从22.8 kg/m3减小到15.2 kg/m3时，对于第一次和第二次注射，尖端穿透行进得更快。通过将初始气体温度从900 K降低到800 K，尖端穿透行进得慢得多。这是因为在900 K时高温燃烧出现得很早。第一次喷射的燃烧导致局部速度的增加，并且这种影响随着点火延迟期（ID）的缩短而变得更加明显。在后面的时间，穿透速度几乎与第二次注射相同。此外，当第二喷雾被注入到含有不同关键中间物质的较热环境中时，第二喷射的ID减小。ID的减少还与第二次喷雾赶上第一次喷雾的时间有关。与第一喷射相比，燃料和空气之间的被抑制的混合导致第二喷射中更浓的点火。对于混合物分数大于0.1的富燃料电池，迅速形成甲醛（CH 2 O）。此外，所有这些细胞中的CH 2 O质量分数与第一次注射相比具有更高的值。
ABSTRACT Large eddy simulation coupled with linear eddy model is applied for the simulation of n-dodecane spray flames with multiple injections (0.5 ms injection/0.5 ms dwell/0.5 ms injection). The numerical model is validated by comparing the vapour penetration length at inner condition and the predicted ignition delay times at reacting conditions with the experimental results. Good agreement between the predicted and measured data is observed. The effects of initial conditions, including the initial temperature and ambient gas density on the development of double injections are analyzed. By decreasing the ambient gas density or initial temperature, the appearance of high-temperature kernels is delayed. The tip penetration travels faster both for the first and second injections when the initial gas density is reduced from 22.8 to 15.2 kg/m3 at an initial temperature of 900 K. By decreasing the initial gas temperature from 900 to 800 K, the tip penetration travels much slower. This is because that the high-temperature combustion appears very early at 900 K. The combustion of the first injection leads to the increase in local velocity and this effect becomes more obvious as the ignition delay (ID) is shortened. At latter times, the penetration velocity is almost the same for the second injection. Moreover, as the second spray is injected into hotter environment containing different key intermediate species, ID is reduced for the second injection. The reduction in ID is also related to the time when the second spray catches up with the first one. The inhibited mixing between fuel and air leads to richer ignition in the second injection compared with the first injection. For fuel-rich cells with the mixture fraction greater than 0.1, formaldehyde (CH2O) is quickly formed. Moreover, CH2O mass fractions in all of these cells have higher values compared with the first injection.
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影响因子：
2.5
作者：
D. Jarrahbashi;Sayop Kim;Benjamin Knox;C. Genzale
通讯作者：
D. Jarrahbashi;Sayop Kim;Benjamin Knox;C. Genzale
影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1016/j.proci.2008.05.077
发表时间：
2009
期刊：
--
影响因子：
--
作者：
B. Sen;S. Menon
通讯作者：
B. Sen;S. Menon
影响因子：
4.4
作者：
Y. Pei;S. Som;E. Pomraning;P. Senecal;S. Skeen;J. Manin;L. Pickett
通讯作者：
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