Influence of dimethyl ether and diethyl ether addition on the flame structure and pollutant formation in premixed iso-octane flames
Influence of dimethyl ether and diethyl ether addition on the flame structure and pollutant formation in premixed iso-octane flames
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DOI：
10.1016/j.combustflame.2017.05.028
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发表时间：
2017-10
影响因子：
4.4
通讯作者：
Meirong Zeng;J. Wullenkord;Isabelle Graf;K. Kohse-Höinghaus
中科院分区：
文献类型：
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作者：
Meirong Zeng;J. Wullenkord;Isabelle Graf;K. Kohse-Höinghaus
虽然已经详细研究了许多单独燃料在火焰中的燃烧反应，通常提供了许多实验物种概况，并结合动力学模型的开发和关键测试，但关于燃料混合物的类似工作仍然很少，特别是对于常规燃料和生物燃料的混合物。因此，在本研究中，我们选择了异辛烷作为基础燃料，二甲醚（DME）和二乙醚（DEE）作为潜在的生物衍生燃料组分，异辛烷是决定汽油辛烷值和爆震倾向的主要参考燃料之一。本文系统地研究了不掺加DME或DEE以及掺加DME或DEE的异辛烷低压预混火焰，分析了掺混后火焰结构和组分组成的变化。所有的火焰都是在40毫巴（4千帕）的压力下，50%氩气稀释和60 cm s-1的冷气体速度下研究的。碳氧比固定在0.47，而当量比从1.47变为1.84。通过电子电离分子束质谱（EI-MBMS），在每个火焰中鉴定和定量了C 0-C9范围内的多达70种物质。此外，还提供了大约300个实验物种的概况。首先，一个新的物种数据集的pureiso-octane火焰的报道，因为这种燃料的预混火焰条件下的形态数据是令人惊讶的稀缺。第二，DME和DEE添加量增加的异辛烷基火焰的影响进行了研究，特别注意火焰结构和污染物物种的形成。第三，联合燃烧模型foriso-octane，二甲醚，和DEE混合物组成的379种和1931反应提出了对目前的数据和参考实验的条件下的更大范围内进行了检查。利用该混合物模型揭示了醛类、烯烃类和碳烟前体等重要物种的主要生成途径。DME和DEE的加入对异辛烷火焰结构的影响相似，但对C2和C3中间体的影响不同。DME和DEE的加入减少了碳烟前体的形成，同时增加了甲醛的产生。
While the combustion reactions of many individual fuels in flames have been studied in detail, often providing numerous experimental species profiles in combination with the development and critical testing of kinetic models, similar work on fuel mixtures has remained scarcer, especially for blends of conventional and biogenic fuels. In the present study, we have thus choseniso-octane, one of the primary reference fuels that determine octane number and knocking tendency of gasoline, as the base fuel, and dimethyl ether (DME) and diethyl ether (DEE) as potentially bio-derived fuel components. Premixed low-pressure flames ofiso-octane without and with different amounts of DME or DEE, of up to 50% of the fuel in the mixture, have been investigated systematically to analyze the change of the flame structure and species composition upon blending. All flames were studied at a pressure of 40 mbar (4 kPa) with 50% argon dilution and a cold gas velocity of 60 cm s−1. The carbon-to-oxygen ratio was fixed at 0.47 while the equivalence ratio changed from 1.47 to 1.84. Up to 70 species in the range of C0–C9were identified and quantified in each flame by electron ionization molecular-beam mass spectrometry (EI-MBMS). Moreover, about 300 experimental species profiles were provided.The aim of this study is thus threefold. First, a new species dataset for a pureiso-octane flame is reported, since speciation data under premixed flame conditions for this fuel is surprisingly scarce. Second, the effects of DME and DEE addition in increasing amounts to theiso-octane base flame are investigated with special attention to the flame structure and pollutant species formation. Third, a joint combustion model foriso-octane, DME, and DEE mixtures consisting of 379 species and 1931 reactions is proposed that was examined against the present data and reference experiments for a larger range of conditions. Key pathways of interesting species, including aldehydes, alkenes, and soot precursors were revealed with the present mixture model. DME and DEE addition were found to have a similar influence on the flame structure ofiso-octane, except for some C2and C3intermediates. The addition of DME as well as of DEE decreases the formation of soot precursors while it enhances the production of formaldehyde.