The ignition delay times (IDTs) of n-alcohol/diesel blends were measured in a heated shock tube (ST) and a heated rapid compression machine (RCM). Three sets of blends were formulated to investigate the effect of n-alcohol (the volume ratio of n-alcohol/diesel being 20%/80% for four blends), cetane number (CN = 43, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 20.5%/79.5% n-propanol/diesel, 23.5%/76.6% n-butanol/diesel, 25.8%/74.2% n-pentanol/diesel), and oxygen content (mass fraction of oxygen w_O2 = 6.65%, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 25.6%/74.4% n-propanol/diesel, 31.4%/68.6% n-butanol/diesel, 37.2%/62.8% n-pentanol/diesel) on the autoignition characteristics. In the RCM temperature region, the IDTs decrease with increasing n-alcohol chain length from ethanol to n-pentanol for all three sets of blends, while those in the ST temperature region show indiscernible variations. Interestingly, the intersection of IDTs for ethanol/diesel blend with other n-alcohol/diesel blends is observed when the temperature is below ~700 K. A recently-released detailed mechanism from the CRECK modeling group was used to predict the experimental results. The simulations show relatively good agreement with high-temperature (HT) ignition data, while the mechanism pronouncedly overpredicts the reactivity of blends at low-to-intermediate temperatures. Sensitivity analyses at three temperatures of 675 K, 800 K, and 1300 K were conducted to identify the dominant reactions during the autoignition of 20% n-alcohol/80% diesel blends and to kinetically elaborate and discuss the discrepancies between simulations and experiments. At the end, a preliminary mechanism tune-up was carried out grounded on the sensitivity analyses. The improved mechanism regains its predictive ability for IDTs of 20% n-butanol/80% diesel blend at RCM temperatures, while fails to precisely simulate the remaining three blends.

在加热的冲击管（ST）和加热的快速压缩机（RCM）中测量n-醇/柴油混合物的点火延迟时间（IDT）。配制了三组共混物以研究正酒精的影响（四种共混物的正酒精/柴油体积比为20％/ 80％），十六烷值（CN = 43，正酒精/柴油体积比）柴油为20％/ 80％乙醇/柴油，20.5％/ 79.5％正丙醇/柴油，23.5％/ 76.6％正丁醇/柴油，25.8％/ 74.2％正戊醇/柴油）和氧气含量（质量氧气含量w _O2 = 6.65％，正酒精/柴油的体积比为20％/ 80％乙醇/柴油，25.6％/ 74.4％正丙醇/柴油，31.4％/ 68.6％正丁醇/柴油，37.2％/ 62.8％正戊醇/柴油）的自燃特性。在RCM温度区域中，对于所有三组共混物，IDT随从乙醇到正戊醇的n醇链长的增加而降低，而ST温度区域中的IDT则显示出明显的变化。有趣的是，当温度低于约700 K时，观察到乙醇/柴油混合物的IDT与其他正醇/柴油混合物的交集。CRECK模型组最近发布的详细机制被用来预测实验结果。仿真结果表明，该数据与高温（HT）点火数据相对较好，而该机制明显低估了混合物在中低温度下的反应性。在675 K，800 K和1300 K的三个温度下进行了敏感性分析，以识别20％正酒精/ 80％柴油混合物自燃过程中的主要反应，并从动力学上阐述并讨论了模拟与实验之间的差异。最后，基于敏感性分析进行了初步的机制调整。改进的机制恢复了其在RCM温度下对20％正丁醇/ 80％柴油混合物的IDT的预测能力，而无法精确模拟其余三种混合物。在1300 K和1300 K的条件下进行了实验，以确定20％正酒精/ 80％柴油共混物自燃过程中的主要反应，并从动力学上阐述和讨论了模拟与实验之间的差异。最后，基于敏感性分析进行了初步的机制调整。改进的机制恢复了其在RCM温度下对20％正丁醇/ 80％柴油混合物的IDT的预测能力，而无法精确模拟其余三种混合物。在1300 K和1300 K的条件下进行了实验，以确定20％正酒精/ 80％柴油共混物自燃过程中的主要反应，并从动力学上阐述和讨论了模拟与实验之间的差异。最后，基于敏感性分析进行了初步的机制调整。改进的机制恢复了其在RCM温度下对20％正丁醇/ 80％柴油混合物的IDT的预测能力，而无法精确模拟其余三种混合物。