掺烧DME对某型柴油机燃烧和排放性能仿真研究

Effect of Dimethyl Ether on Combustion and Emission Performance of a Marine Diesel Engine

本文基于TBD234V6型增压柴油机,采用AVL-fire软件对柴油机额定工况下,0%、10%、20%及30%共四组二甲醚掺混比进行三维数值模拟研究,结果表明:额定工况下,与纯柴油相比,随着二甲醚掺混比增加,缸内爆压与温度峰值随之下降,且相应的曲轴转角均推迟,30%掺混比,下降幅度最大,下降率分别约10.3%、7.8%,曲轴转角分别推迟约2°CA和2.2°CA;CO生成质量分数随之升高;NO生成质量分数下降明显,最大降幅约66.8%;Soot排放整体呈先升高后降低的趋势.因此,掺烧DME能显著改善柴油机NO排放性能,但也一定程度上弱化了柴油机动力性,后期可通过调整柴油机喷射规律加以完善,研究结果可为掺烧二甲醚实船应用提供一定的指导依据.

This paper is based on the TBD234V6 supercharged diesel engine,using AVL-fire software to determine the diesel engine under rated operating conditions,0%,10%,20%and 30%,a total of four groups of two A three-dimensional numerical simulation study on the mixing ratio of methyl ether showed that compared with pure diesel under rated conditions,as the mixing ratio of dimethyl ether increased,the explosion pressure and temperature peak in the cylinder decreased,and the corresponding crankshaft The rotation angles are all delayed.When the blending ratio is 30%,the decrease is the largest,which decreases by about 10.3%and 7.8%respectively.The crankshaft angle is delayed by about 2°CA and 2.2°CA;the mass fraction of CO production increases accordingly;the mass fraction of NO production increases.The decline is obvious,with the largest drop of about 66.8%%;Soot emissions as a whole show a trend of first increasing and then decreasing.Therefore,blending dimethyl ether can significantly improve the NO emission performance of diesel engines,but it also weakens the power of diesel engines.In the later stage,it can be improved by adjusting the injection law of diesel engine,and the research results can provide a certain guiding basis for the application of burning dimethyl ether in real ships.