摘要
用CFD多维数值分析软件对BUMP燃烧室内柴油喷雾的撞壁混合过程进行了模拟计算,并与用PLIF法取得的试验结果进行了对比,二者基本吻合。试验和模拟计算结果均表明,撞壁射流在遇到BUMP后会剥离燃烧室壁面,形成二次空间射流,扩大撞壁射流与空气的空间混合体积及混合速率,出现与周围空气迅速混合的闪混现象,燃烧室壁面燃油堆积量下降。计算结果还表明,BUMP的位置、高度、形状和角度不同对形成二次空间射流及稀混合气的作用也不相同,在实际应用中应对其进行优化和合理匹配,以便降低柴油机的NOx和碳烟排放。
Numerical simulations of the wallimpingement mixing process of a diesel spray in the BUMP combustion chamber were carried out by means of a CFD multidimensional numerical analysis code. The computed results agreed well with the experimental ones obtained by planar laserinduced fluorescence (PLIF) method by comparison. Both measured and computed results indicated that the wallimpingement jet would stripped off the combustion chamber surface and formed a secondary space jet when it met with the BUMP on the wall. This resulted in the rises of space mixing volume and mixing rate of the wallimpingement jet with the surrounding air, and a flash mixing phenomenon of rapid mixing of diesel fuel with air appeared. And the amount of fuel accumulated on the wall decreased. The computational results also showed that the location, height, shape and angle with the chamber wall of a BUMP on the wall had significant effects on the formation of a secondary space jet and lean mixture and should be optimized and matched rationally in practical applications in order to reduce NOx and soot emissions of diesel engines.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2003年第6期389-394,共6页
Transactions of Csice
基金
国家自然科学基金重点项目"车用内燃机新概念燃烧过程"(59936130)
国家重点基础研究发展规划项目"新一代内燃机燃烧理论"(2001CB209202)。
