中文摘要：

基于大涡模拟LES（1arge eddy simulation）理论和VOF（Volume of Fluid）方法，考察了燃油喷雾初始时刻即时间尺度为微秒级的液柱破碎过程，分析了初始破碎的机理，给出了该时间尺度下液柱初始破碎过程的模型；通过对一特定条件下的柴油机喷油器的建模和喷雾过程的大涡数值模拟，获得了液柱初始时刻“伞状头部”的喷雾形态，所得计算结果与相应的试验数据符合较好；数值模拟还直观地展现了液滴背风RT破碎、哑铃型破碎以及液滴的聚集融合等液滴的二次雾化过程。同时，也说明了大涡模拟这种准直接数值方法较之DDM（discrete droplets model）方法所具有的优势和潜力。

英文摘要：

Based on the theory of large eddy simulation （LES） and the method of VOF （ Volume of Fluid）, the initial breakup process of fuel liquid jet, which eject from the nozzle exit at the time scale of micro-second level, is investigated. The mechanism of primary atomization is analyzed, and the initial （at that time） breakup model of liquid jet is presented. By modeling and numerical simulation of atomization for a diesel nozzle under the given conditions, the initial umbrella-like spray shapes are obtained, which fits better with the experimental results. Meanwhile, the droplets secondary breakup process, such as leeward RT breakup, dumbbell-like breakup and droplets coalescence, etc. are exhibited visually. It is proved that the LES method, which is also called quasi-DNS （direct numerical simulation）, has more powerful potential compared with the method of DDM （ discrete droplets model）.