对醇类燃料(甲醇和乙醇)进行了高压旋流喷雾特性的试验和数值模拟的研究。试验研究表明,醇类燃料的旋流喷射在油束的外形结构上与汽油类似:在低背压条件下油束分布宽广,喷雾总体形状为中空锥形结构,且在主喷雾前端存在初始喷雾液团。在高背压条件下油束紧密宽度减小,整个油束喷雾呈现出实心圆锥的形状。在油束两侧边缘有两个相对旋转的涡流结构,低背压条件下涡旋出现在油束中后部两侧边缘,高背压条件下出现在油束中部两侧边缘。甲醇、乙醇与汽油旋流喷雾的贯穿度曲线基本上重叠在一起。甲醇喷雾锥角最大,乙醇和汽油则差别很小。数值模拟表明,甲醇和乙醇旋流喷雾的SMD比汽油略大。低背压时,甲醇和乙醇SMD曲线几乎重叠在一起。随背压增大,由于甲醇蒸发性大于乙醇,极小液滴汽化,导致甲醇的SMD比乙醇略大。数值模拟比较准确地模拟了高压旋流喷雾的涡旋现象。
High-pressure swirl injection using methanol and ethanol was studied with experiments and numerical simulation. Experiments show that swirl injection of methanol and ethanol has the same trend as that of gasoline: under low back pressure the spray is a hollow cone and spread widely with initial spray at the tip, while the spray is a solid cone under higher back pressure. Swirls in opposite direction exist on both side of the spray, locating at the middle-rear part of the spray under low back-pressure while it is in the middle part under high back-pressure. Experiments also showed that methanol has the biggest cone angle, ethanol and gasoline have almost the same cone angle. Numerical simulation indicated that for swirl injection, methanol and ethanol have a little larger SMD than that of gasoline. The SMD curves of methanol coincide with those of ethanol under low back-pressure, but gives a little larger value under higher back-pressure due to the evaporation. Numerical simulation also clearly demonstrates the swirling phenomena of the high-pressure swirl injection.