Experimental and modeling study on the autoignition characteristics of methyl stearate in a rapid compression machine
Experimental and modeling study on the autoignition characteristics of methyl stearate in a rapid compression machine
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DOI：
10.1016/j.combustflame.2023.112942
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发表时间：
2023-07-11
影响因子：
4.4
通讯作者：
Lu，Xingcai
中科院分区：
文献类型：
--
作者：
Zhou，Wei;Liang，Yueying;Lu，Xingcai
随着对先进燃烧模式的广泛探索以及对极高效率和低排放发动机的需求日益增加，生物柴油作为一种拥有广泛原材料的可再生燃料来源，已获得了极大的关注和研究。在新型加热式快速压缩机（RCM）上测定了生物柴油的主要组分之一硬脂酸甲酯的着火延迟时间（IDT）。在当量比为0.3-0.8和压缩温度为820 K至1000 K的情况下，在8、10和12 bar的三种不同压力下获得了数据。在实验条件下，系统地讨论了压缩温度、压缩压力、当量比和氧摩尔分数对着火延迟时间的影响，揭示了硬脂酸甲酯在中温条件下的自燃特性。此外，CRECK模型和骨架模型与实验结果进行了验证，表明类比获得的模型显着高估了硬脂酸甲酯的低温反应活性。此外，在敏感性分析的基础上，对CRECK模型中低温基元反应的指前因子进行了适当的调整。结果表明，优化后的模型能较好地反映出叉指换能器在不同工作条件下的性能变化，模拟结果与实验数据吻合较好。最后，通过激波管和射流搅拌反应器的实验数据对优化模型进行了验证。据作者所知，这项研究代表了纯硬脂酸甲酯，这是一个蜡状固体在室温下进行的第一个气相RCM实验。
With the extensive exploration of advanced combustion modes and the increasing demand for engines with extremely high efficiency and low emissions, biodiesel has garnered significant attention and research as a renewable fuel source that boasts a wide range of raw materials. The ignition delay times (IDT) of methyl stearate, one of the main components in biodiesel, were measured in a new heated rapid compression machine (RCM). The data were obtained for the equivalence ratio of 0.3–0.8 and the compressed temperatures ranging from 820 K to 1000 K under three different pressures of 8, 10, and 12 bar. The influence of compressed temperature, compressed pressure, equivalence ratio, and oxygen mole fraction on ignition delay times was systematically discussed under experimental conditions, revealing the autoignition characteristics of methyl stearate in intermediate temperatures. Besides, the CRECK model and a skeletal model were verified against the experimental results, revealing that the model obtained by analogy significantly overestimates the low-temperature reactivity of methyl stearate. Furthermore, appropriate adjustments were made to the pre-exponential factors for the low-temperature elementary reactions in the CRECK model based on sensitivity analysis. The results indicate that the present model with optimization can well capture the dependence of the IDTs on the operating parameters under the investigated conditions, and the simulation results are in satisfactory agreement with the experimental data. Finally, the optimized model was verified against the experimental data from both the shock tube and jet-stirred reactor. To the authors' knowledge, this study represents the first gas-phase RCM experiment conducted on pure methyl stearate, which is a waxy solid at room temperature.