Development and validation of an n-dodecane skeletal mechanism for spray combustion applications
Development and validation of an n-dodecane skeletal mechanism for spray combustion applications
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DOI：
10.1080/13647830.2013.872807
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发表时间：
2014-03
影响因子：
1.3
通讯作者：
Zhaoyu Luo;S. Som;S. M. Sarathy;M. Plomer;W. Pitz;D. Longman;T. Lu
中科院分区：
文献类型：
--
作者：
Zhaoyu Luo;S. Som;S. M. Sarathy;M. Plomer;W. Pitz;D. Longman;T. Lu
正十二烷是一种很有前途的柴油机代用燃料，因为它的物理化学性质与实际柴油相似。在本研究中，一个骨架机制，正十二烷的105个物种和420个反应的喷雾燃烧模拟。还原开始于劳伦斯利弗莫尔国家实验室开发的由2755种物质和11，173个反应组成的正构烷烃的最新详细机制。采用直接关系图与专家知识（DRGX）和灵敏度分析相结合的算法进行骨架约简。骨架机理首先在0-D和1-D燃烧系统中得到了广泛的验证，包括自燃、喷射搅拌反应器（JSR）、层流预混火焰和逆流扩散火焰。然后将其与成熟的喷雾模型耦合，并在类似发动机条件下的三维湍流喷雾燃烧模拟中进一步验证。这些模拟进行了比较，最近的实验与正十二烷作为柴油燃料的替代品。可以看出，燃烧特性，如点火延迟和火焰升离长度很好地捕获的骨架机制，特别是在高环境温度的条件下。模拟也捕捉瞬态火焰发展现象相当不错。结果进一步表明，点火延迟可能不是控制本火焰稳定的唯一因素，因为点火延迟的良好匹配不一定导致改进的火焰离地长度预测。
n-Dodecane is a promising surrogate fuel for diesel engine study because its physicochemical properties are similar to those of the practical diesel fuels. In the present study, a skeletal mechanism for n-dodecane with 105 species and 420 reactions was developed for spray combustion simulations. The reduction starts from the most recent detailed mechanism for n-alkanes consisting of 2755 species and 11,173 reactions developed by the Lawrence Livermore National Laboratory. An algorithm combining direct relation graph with expert knowledge (DRGX) and sensitivity analysis was employed for the present skeletal reduction. The skeletal mechanism was first extensively validated in 0-D and 1-D combustion systems, including auto-ignition, jet stirred reactor (JSR), laminar premixed flame and counter flow diffusion flame. Then it was coupled with well-established spray models and further validated in 3-D turbulent spray combustion simulations under engine-like conditions. These simulations were compared with the recent experiments with n-dodecane as a surrogate for diesel fuels. It can be seen that combustion characteristics such as ignition delay and flame lift-off length were well captured by the skeletal mechanism, particularly under conditions with high ambient temperatures. Simulations also captured the transient flame development phenomenon fairly well. The results further show that ignition delay may not be the only factor controlling the stabilisation of the present flames since a good match in ignition delay does not necessarily result in improved flame lift-off length prediction.