预燃室参数对大缸径天然气发动机燃烧过程影响的研究

Influence of Pre-Chamber Parameters on Combustion Process in Large Natural Gas Engine

在对大缸径天然气发动机燃烧系统开发的过程中,设计了小容积预燃室加浅盆型主燃室的燃烧系统,之间通过8个直径2mm的均匀布置的通道连接,针对2种角度的布置结构进行数值模拟及试验分析。通过简化的甲烷反应动力学模型模拟分析了主燃室内的燃烧过程。分析结果表明:大的连接通道夹角有利于加快燃烧室径向的火焰传播速度,但主燃室中心部位燃烧较慢;小夹角的方案则相反。单缸试验机上的试验也得到了相同的结果,并证明大夹角通道方案有较好的抗爆震性能和排放性能。

Combustion systems for large natural gas engine were designed, which included a small volume pre-combustion chamber and a shallow basin shape main combustion chamber connected between them by eight equally-spaced holes of dia. 2 mm. Two schemes of connected hole angle were studied by CFD simulation and experimental method. Combustion process in the main chamber was simulated using simplified methane reaction kinetic model. Results show that in the big included angle scheme the flame radial propagation is accelerated and burn at the combustion chamber centre is slow, while the trend is contrary with the small included angle one. The same results are demonstrated by single cylinder engine test. In addition, the big included angel scheme has better anti-knocking ability and emissions.