A comparative study on ignition delay time and combustion characteristics of four typical oxygenated fuel/air mixtures of dimethyl ether (DME), diethyl ether (DEE), ethanol and E92 ethanol gasoline was conducted through the chemical shock tube. The fuel/air mixtures were measured under the ignition temperature of 1100 to 1800 K, initial pressure of 0.3 MPa and the equivalence ratios of 0.5, 1.0 and 1.5. The experimental results show that the ignition delay time of these four oxygenated fuels satisfies the Arrhenius relation. The reaction H + O₂ = OH + O has a high sensitivity in four fuel/air mixtures during high‐temperature ignition, which makes the ignition delay lengthen with the increase of the equivalence ratios. By comparing the ignition delay of four fuels, ether fuels have excellent ignition performance and ether functional group has better ignition promotion than hydroxyl group. Moreover, the carbon chain length also significantly promotes the ignition. Due to the accumulation of a large number of active intermediates and free radicals during the long ignition delay time before ignition, the four fuels all have intense deflagration and generate the highest combustion peak pressure at the relatively low ignition temperature (1150‐1300 K). For DME, DEE and ethanol, due to the high content of oxygen in their molecules, the combustion peak pressure and luminous intensity increased with the equivalence ratio, and the combustion is intense after ignition. E92 ethanol gasoline with low oxygen content has a lower combustion peak pressure and a longer combustion duration than the other three fuels, and its highest combustion peak pressure appears in the stoichiometric ratio. The combustion process of E92 ethanol gasoline is more oxygen‐dependent than the other three fuels.

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冲击管研究高温下含氧燃料的点火延迟和燃烧特性

通过化学冲击管对四种典型的含氧燃料/空气混合物（二甲醚（DME），二乙醚（DEE），乙醇和E92乙醇汽油）的点火延迟时间和燃烧特性进行了比较研究。在点火温度为1100至1800 K，初始压力为0.3 MPa，当量比为0.5、1.0和1.5的条件下测量燃料/空气混合物。实验结果表明，这四种含氧燃料的点火延迟时间均满足阿伦尼乌斯关系式。反应H + O ₂= OH + O在高温点火期间对四种燃料/空气混合物具有很高的灵敏度，这使得点火延迟随着当量比的增加而延长。通过比较四种燃料的点火延迟，醚燃料具有优异的点火性能，醚官能团的点火促进性优于羟基。此外，碳链长度也显着促进了点火。由于在点火前很长的点火延迟时间内大量的活性中间体和自由基的积累，这四种燃料都具有强烈的爆燃并在相对较低的点火温度（1150-1300 K）下产生最高的燃烧峰值压力。对于DME，DEE和乙醇，由于分子中的氧气含量很高，燃烧峰值压力和发光强度随当量比的增加而增加，点火后燃烧剧烈。含氧量低的E92乙醇汽油的燃烧峰值压力较低，燃烧持续时间长于其他三种燃料，其最高燃烧峰值压力以化学计量比出现。E92乙醇汽油的燃烧过程比其他三种燃料对氧气的依赖性更大。