船用低速二冲程柴油机燃烧与排放数值模拟研究

使用CFD软件对一台船用低速二冲程柴油机额定工况点缸内喷雾、燃料着火和燃烧过程、排放物NOx浓度分布及生成总量进行了数值模拟研究。模拟所得压缩压力和最高燃烧压力与实测值基本一致。在额定工况点运行时,柴油机预混合燃烧比例很小,基本呈现单峰状的扩散燃烧特征;燃烧放热初始时刻在上止点附近,整个燃烧持续期约为45℃A。同时,计算所得的NOx生成总量与实测值存在19.15%的偏差。

Simulation Research on the Combustion and Emissions of Marine Low-speed Two Stroke Diesel Engine

CFD software was used to carry out simulation research on a marine low-speed two stroke diesel engine about its in cylinder spray,ignition and combustion process,NOx emission concentration distribution and total amount under the rated operating mode.The simulated compression pressure and maximum combustion pressure are basically the same with measured results.The pre-mixing combustion occupies very small percentage,and basically show the unimodal diffusion combustion characteristics.The initial combustion exothermic takes place around the TDC,and the whole combustion duration lasts for 45℃A.The calculated total amount of NOx emission is 19.15 % deviate from the measured value.