高浓度CO2对柴油着火延迟特性的影响

Effects of High Concentration CO2 on Diesel Ignition Delay Characteristics

为了研究柴油在高浓度CO2环境中的着火延迟特性,提出适用于该环境下的着火延迟时间公式。该公式考虑了CO2的热效应和第三体效应对着火延迟的影响,分析了CO2浓度与着火延迟的关系,运用Chemkin模拟了CO2对OH自由基生成速率的影响。对该环境下柴油的着火问题进行了定容燃烧弹的可视化实验研究和仿真计算。结果表明:着火延迟时间公式在CO2物质的量分数小于60%时能够有效表达CO2对着火延迟时间的影响;CO2物质的量分数大于60%时,反应H2O2+M→20H+M中的第三体效率降低导致着火延迟增长变慢。

In order to study ignition delay characteristics of diesel in high concentration CO2 environment,an ignition delay time formula was proposed,which considered thermal effect and third body effect of CO2 on ignition delay.The relationship between CO2 concentration and ignition delay was analyzed then.The CO2 effect on OH radicals formation rate was simulated by Chemkin software.The visualized experimental research and simulation of constant-volume combustion bombs were carried out for diesel ignition in this environment.The results show that the ignition delay time formula can effectively describe the CO2 effect on the ignition delay time when the CO2 volume fraction is less than 60%.In reaction H2O2+M→20H+M,the decrease of third body efficiency leads to a slower growth of ignition delay when the CO2 volume fraction is more than 60%.