掺烧乙醇/水对柴油机燃烧与排放性能的影响

针对TBD234V6型柴油机,采用AVL-fire软件对额定工况下,不同乙醇/水掺混比进行三维数值模拟研究,对比分析缸内压力、缸内温度、缸内温度场、燃烧放热率、NOx浓度、NOx浓度场、Soot浓度、Soot浓度场,并通过赋权法确定最优乙醇/水掺混比。结果表明：随着乙醇/水掺混比的增加，缸内压力逐渐升高，燃烧放热率滞后，燃油消耗率呈上升趋势，但在0E10W时，最高燃烧压力下降率约为3.7%；燃油消耗率下降0.38%；缸内高温分布区域缩小，NOx和Soot浓度下降。通过计算确定最优掺混比为20E10W，此时，最高燃烧压力提升5.6%，燃油消耗率上升2.41%，NOx排放下降率约为18.8%，Soot排放下降率约为29.6%。研究结果可为船用柴油机采用柴油/乙醇/水三燃料燃烧提供一定的指导依据。

Effect of Blending Ethanol/Water on Combustion and Emission Performance of Diesel Engine

For the TBD234V6 diesel engine, AVL-fire software is used to carry out three-dimensional numerical simulation research on different ethanol/water mixing ratio under rated conditions, and compare and analyze cylinder pressure, cylinder temperature, cylinder temperature field, combustion heat release rate and NOx. Concentration, NOx concentration field, Soot concentration, Soot concentration field, and the optimal ethanol/water blending ratio was determined by the weighting method. The results show:With the increase of ethanol/water blending ratio, the in-cylinder pressure and the fuel consumption rate increases, but the combustion heat release rate lags. However, at 0E10W, the maximum combustion pressure drop rate is about 3.7%; the fuel consumption rate drops by 0.38 %; the high temperature distribution area in the cylinder is reduced, and the NOx and Soot concentrations are decreased. The optimal blending ratio was determined to be 20E10W. At this time, the maximum combustion pressure increased by 5.6%, the fuel consumption rate increased by 2.41%, the NOx emission reduction rate was about 18.8%, and the Soot emission reduction rate was about 29.6%. The research results can provide a certain guidance for the use of diesel/ethanol/water three fuel combustion for marine diesel engines.