柴油在O_2/CO_2环境下的燃烧特性分析

Analysis of Combustion Characteristics of Diesel Oil in O_2/CO_2 Environment

为了降低柴油机NO_x和碳烟(soot)的排放,对基于O_2/CO_2环境的柴油机燃烧新模式进行了研究,运用KIVA-3V软件对柴油在定容燃烧弹内模拟发动机上止点的燃烧过程进行了数值仿真,对定容燃烧弹内柴油燃烧压力曲线进行了数值模拟分析,最后在定容燃烧弹上对正常空气环境下和O_2/CO_2浓度为50%/50%环境下的柴油燃烧过程进行了可视化研究.仿真结果表明,柴油在O_2/CO_2环境下的着火延迟时间相比在正常空气环境下要有所缩短;随着喷油压力的增高,柴油的雾化混合效果变好,燃烧更加充分,使得容弹内柴油的最大燃烧压力升高.定容燃烧弹可视化试验表明,柴油在O_2/CO_2环境下可以进行预混合自燃及扩散燃烧,同时得到的理想"瓢"型火焰图像表明柴油在O_2/CO_2环境下可以稳定燃烧.

In order to reduce the emission of NO and soot of diesel engine, the new combustion mode of diesel engine based on O2/CO2 environment is studied. Numerical simulation for the combustion process of diesel oil in the constant volume combustion bomb was carried out by using KIVA-3V software. And the diesel combustion pressure curve in constant volume combustion bomb is analyzed. Finally, the combustion process of diesel oil was studied in the constant volume combustion bomb and with the condition of 50% O2/50% CO2 environment and air environment. The simulation results show that the ignition delay time of diesel oil in O2/CO2 environment is shorter than that in air environment. Besides, with the increase of injection pressure, the mixing effect of diesel oil becomes better, and the combustion is more sufficient, so that the maximum combustion pressure of the diesel engine is increased. Constant volume combustion bomb visualization experiments show that the combustion of diesel in O2/CO2 environment is premixed combustion and diffusion combustion, and the ideal ＂scoop＂ type flame images show that diesel in O2/CO2 environment can burn stably.