祝传艮，李研芳，刘志宇

中国北方发动机研究所，天津 300400

摘要：为研究煤层气发动机燃烧室结构对燃烧特性的影响，建立燃烧仿真模型；根据影响燃烧室结构的压缩余隙、坑口直径和坑底圆角半径3个参数设计4种燃烧室方案，利用三维软件Converge仿真分析不同燃烧室方案对发动机缸内燃烧过程的影响。结果表明：较小的压缩余隙可以促进缸内流体运动，有利于减小燃烧室未燃区体积，对燃烧过程有利；增大坑底圆角半径不利于提高缸内气流的流动，对燃烧过程不利；在小范围内优化坑口直径对提升发动机燃烧性能作用不明显。

关键词：煤层气发动机；燃烧室；压缩余隙；坑口直径；坑底圆角半径

Abstract：In order to study the influence of the combustion chamber structure of the coalbed methane engine on the combustion characteristics, a combustion simulation model is established, and 4 combustion chamber schemes are designed according to the 3 parameters affecting the combustion chamber structure: compression clearance, pit diameter and pit bottom fillet radius. The Converge software conducts combustion simulation analysis for different combustion chamber schemes respectively. The results show that the smaller compression clearance can promote the fluid movement in the cylinder, and the smaller compression clearance is also beneficial to reduce the volume of the unburnt area of the combustion chamber,which is beneficial to the combustion process. Increasing the radius of the pit bottom is not conducive to improve the flow of air in the cylinder, which is unfavorable to the combustion process.Optimizing the pit diameter in a small range has little effect on combustion performance.

Keywords:coalbed methane engine; combustion chamber; pit diameter; pit bottom fillet radius