RO2 and QOOH Chemistry in Dimethylether Combustion

二甲醚（DME，CH 3 OCH 3）作为一种替代清洁燃料具有相当大的潜力。它的能量密度类似于目前的生物燃料，如乙醇，与现有的发动机技术兼容，燃烧时氮氧化物和烟尘排放量低，并可通过现有的液化石油气网络分配。然而，对于DME的“低温”（500 - 900 K）燃烧知之甚少;在此温度范围内的燃烧在较新的发动机技术如HCCI（均质充气压缩点火）中特别重要。本研究旨在探讨二甲醚燃烧的机理，为燃烧学界和工业界提供有用的信息。该建议是相匹配的EPSRC在能源research.There的优先事项已经有一些以前的研究低温二甲醚氧化，但没有以前的研究已经能够观察到自由基中间体直接或从表面上的反应的潜在并发症。在目前的建议中，我们将使用一种新型的高温（高达900 K），高压（高达5个大气压）湍流管提供一个无壁反应器适合于研究高达几百毫秒的时间尺度上的自由基反应。流管将直接连接到一个用于自由基检测的低压荧光池和一个用于检测链增长和链支化反应（例如CO和甲醛）的拟议产物的飞行时间质谱仪。我们的实验将探讨链增长（受控氧化）和链支化（爆炸氧化）之间的竞争作为温度和压力的函数。观察自由基和稳定的产品，结合使用同位素标记的前体，将使我们能够确定DME氧化的分子机制。实验结果将与利兹大学和阿贡国家实验室（Klippenstein和Harding博士）进行的理论计算相结合，以全面了解该机制，并使我们能够将结果外推到更宽的温度和压力范围。这项工作的影响将与亨利柯伦博士一起进行评估（高威大学燃烧化学中心主任）通过更新的二甲醚燃烧动力学模型，并与激波管或发动机模拟的最终产品研究进行比较，这项工作具有明显的实际和商业意义，我们正在与福特和国际二甲醚协会合作（IDA，并通过IDA到沃尔沃技术和劳斯莱斯等组织），以提高EPSRC投资的影响力。

Dimethylether (DME, CH3OCH3) has considerable potential as an alternative clean fuel. It has energy densities similar to current biofuels such as ethanol, is compatible with existing engine technologies, burns with low NOx and soot emissions and can be distributed via available LPG networks. However, relatively little is known about the 'low temperature' (500 - 900 K) combustion of DME; combustion in this temperature range is particularly important in newer engine technologies such as HCCI (homogeneously charged compression ignition). This proposal seeks to characterise the mechanisms of DME combustion providing useful information to the academic combustion community and industrial collaborators. The proposal is matched to EPSRC priorities in energy research.There have been a number of previous studies on low temperature DME oxidation, but no previous study has been able to observe radical intermediates directly or to be free from potential complications of reactions on surfaces. In the current proposal we will use a novel high temperature (up to 900 K), high pressure (up to 5 atm) turbulent flow tube providing a wall-less reactor suitable for studying radical reactions on time scales of up to several hundred milliseconds. The flow tube will be directly interfaced to a low pressure fluorescence cell for radical detection and a time-of-flight mass spectrometer for detection of the proposed products from chain propagation and chain branching reactions (e.g. CO and formaldehyde).Our experiments will probe the competition between chain propagation (controlled oxidation) and chain branching (explosive oxidation) as a function of temperature and pressure. Observation of radicals and stable products, in conjunction with the use of isotopically labelled precursors, will allow us to determine the molecular mechanism of DME oxidation. The experimental results will be combined with theoretical calculations carried both at the University of Leeds and Argonne National Laboratory (Drs Klippenstein and Harding) to give a full picture of the mechanism and allow us to extrapolate our results to wider ranges of temperature and pressure. The impact of the work will be assessed in conjunction with Dr Henry Curran (Director, Centre for Combustion Chemistry, University of Galway) via updated kinetic models of DME combustion and comparison with end-product studies from shock tubes or engine simulations.The work has obvious practical and commercial implications and we are working with Ford and the International DME Association (IDA, and through to IDA to organisations such as Volvo Technologies and Rolls Royce) to enhance the impact of EPSRC investment.