分隔室压燃式天然气发动机燃烧过程模拟

3-Dimensional Simulation in Compressed Ignited Natural Gas Engine with a Separated Chamber

为了研究分隔室压燃式天然气发动机燃烧系统的燃烧机理和缸内气体运动的规律,依据该发动机的工作特点以及天然气燃料本身的特性,开发了一简化的天然气化学动力学模型(其中包含23 种组分和74个反应式)。应用相关文献中提供的试验数据,首先对该化学动力学模型的精度进行了验证,然后用所建模型对分隔室压燃式天然气发动机中的燃烧和流动进行了三维模拟计算。模拟计算结果表明,在采取进气预热措施后,天然气在分隔室燃烧室中可以可靠着火,并能迅速燃烧。压缩上止点时在分隔室中存在较强的涡流及副涡流。此外,还对着火时刻及NO排放进行了模拟计算及分析。

In order to study the combustion mechanism and gas flow in cylinder of a compression-ignited natural gas engine with separated chamber,a reduced chemical kinetic controlling model,consisting of 23 chemical species and 74 elementary chemical reactions,is developed.Firstly,this prediction accuracy of the model was validated by using the experimental data from related literatures,and then it was used to make a 3-dimensionnal simulation for combustion and gas flow in a compression-ignited natural gas engine with separated chamber.The simulated results showed that by preheating the inlet air,natural gas can realize the self-ignite in the separated chamber and burn quickly.There exists a strong swirl and auxiliary swirl in combustion chamber when piston reaches the top dead center.Meanwhile,a simulation in the ignition timing and NO emission are also taken and analyzed.