Abstract Chemical reactions in stoichiometric to fuel-rich methane/dimethyl ether/air mixtures (fuel air equivalence ratio ϕ = 1–20) were investigated by experiment and simulation with the focus on the conversion of methane to chemically more valuable species through partial oxidation. Experimental data from different facilities were measured and collected to provide a large database for developing and validating a reaction mechanism for extended equivalence ratio ranges. Rapid Compression Machine ignition delay times and species profiles were collected in the temperature range between 660 and 1052 K at 10 bar and equivalence ratios of ϕ = 1–15. Ignition delay times and product compositions were measured in a shock tube at temperatures of 630–1500 K, pressures of 20–30 bar and equivalence ratios of ϕ = 2 and 10. Additionally, species concentration profiles were measured in a flow reactor at temperatures between 473 and 973 K, a pressure of 6 bar and equivalence ratios of ϕ = 2, 10, and 20. The extended equivalence ratio range towards extremely fuel-rich mixtures as well as the reaction-enhancing effect of dimethyl ether were studied because of their usefulness for the conversion of methane into chemically valuable species through partial oxidation at these conditions. Since existing reaction models focus only on equivalence ratios in the range of ϕ = 0.3–2.5, an extended chemical kinetics mechanism was developed that also covers extremely fuel-rich conditions of methane/dimethyl ether mixtures. The measured ignition delay times and species concentration profiles were compared with the predictions of the new mechanism, which is shown to predict well the ignition delay time and species concentration evolution measurements presented in this work. Sensitivity and reaction pathway analyses were used to identify the key reactions governing the ignition and oxidation kinetics at extremely fuel-rich conditions.

中文翻译：

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极其富含燃料的甲烷/二甲醚混合物反应性的实验和建模研究

摘要 通过实验和模拟研究了化学计量到富含燃料的甲烷/二甲醚/空气混合物（燃料空气当量比 ϕ = 1-20）的化学反应，重点是通过部分氧化将甲烷转化为化学价值更高的物种。测量和收集来自不同设施的实验数据，以提供一个大型数据库，用于开发和验证扩展当量比范围的反应机制。快速压缩机点火延迟时间和物种分布在 660 到 1052 K 之间的温度范围内收集，压力为 10 bar，当量比为 ϕ = 1–15。在 630–1500 K 的温度、20–30 bar 的压力和 ϕ = 2 和 10 的当量比下，在激波管中测量点火延迟时间和产品成分。此外，在 473 到 973 K 之间的温度、6 bar 的压力和 ϕ = 2、10 和 20 的当量比下，在流动反应器中测量物质浓度分布。扩展的当量比范围适用于极其富含燃料的混合物以及研究了二甲醚的反应促进作用，因为它们可用于在这些条件下通过部分氧化将甲烷转化为具有化学价值的物质。由于现有的反应模型仅关注 ϕ = 0.3-2.5 范围内的当量比，因此开发了一种扩展的化学动力学机制，该机制也涵盖了甲烷/二甲醚混合物的极度富燃料条件。将测得的点火延迟时间和物种浓度分布与新机制的预测进行比较，这表明可以很好地预测这项工作中提出的点火延迟时间和物种浓度演变测量。敏感性和反应路径分析用于确定在极度富燃料条件下控制点火和氧化动力学的关键反应。