A reduced mechanism for biodiesel surrogates for compression ignition engine applications
A reduced mechanism for biodiesel surrogates for compression ignition engine applications
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DOI：
10.1016/j.fuel.2012.04.028
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发表时间：
2012-09
期刊：
影响因子：
7.4
通讯作者：
Zhaoyu Luo;M. Plomer;T. Lu;S. Som;D. Longman;S. M. Sarathy;W. Pitz
中科院分区：
文献类型：
--
作者：
Zhaoyu Luo;M. Plomer;T. Lu;S. Som;D. Longman;S. M. Sarathy;W. Pitz
为了降低三维发动机模拟的计算成本，建立了包含115种物质、460种反应的癸酸甲酯、9-癸酸甲酯和正庚烷三组分生物柴油替代物骨架机制。采用劳伦斯利弗莫尔国家实验室（LLNL）开发的生物柴油详细机理作为启动机理。首次更新了详细机理中正庚烷和较大烷烃亚组分的速率常数。然后通过直接关系图（DRG）、异构体集总和DRG辅助敏感性分析（DRGASA）对详细机理进行约简，并对其进行改进，以实现更大程度的约简。在消光和点火应用中，当压力从1到100atm，等效比从0.5到2时，进行了降低。初始点火温度为700 ~ 1800K，覆盖了压缩点火（CI）发动机工况。利用空间均匀系统、一维火焰和三维湍流喷雾燃烧的详细机理和实验数据，对0-D模拟进行了广泛的验证。该骨架机制能够准确预测不同环境条件下的点火延迟、起燃长度、起燃位置等效比等燃烧特性。与包含3299种物质和10806个反应的详细机制相比，骨架机制在保持良好的准确性和全面性的同时，在尺寸上减少了约30倍。
A skeletal mechanism with 115 species and 460 reactions for a tri-component biodiesel surrogate, which consists of methyl decanoate, methyl 9-decenoate and n-heptane, was developed to reduce computational costs for 3-D engine simulations. The detailed mechanism for biodiesel developed by Lawrence Livermore National Laboratory (LLNL) was employed as the starting mechanism. The rate constants for the n-heptane and larger alkane subcomponents in the detailed mechanism were first updated. The detailed mechanism was then reduced with direct relation graph (DRG), isomer lumping, and DRG-aided sensitivity analysis (DRGASA), which was improved to achieve a larger extent of reduction. The reduction was performed for pressures from 1 to 100atm and equivalence ratios from 0.5 to 2 for both extinction and ignition applications. The initial temperatures for ignition were from 700 to 1800K, covering the compression ignition (CI) engine conditions. Extensive validations were performed against 0-D simulations with the detailed mechanism and experimental data for spatially homogeneous systems, 1-D flames and 3D-turbulent spray combustion. The skeletal mechanism was able to predict various combustion characteristics accurately such as ignition delay, flame lift-off length, and equivalence ratio at flame lift-off location under different ambient conditions. Compared with the detailed mechanism that consists of 3299 species and 10806 reactions, the skeletal mechanism features a reduction by a factor of around 30 in size while still retaining good accuracy and comprehensiveness.