启喷阶段高压柴油射流雾化机理的大涡模拟  

LES Simulation of High-Pressure Fuel Jet Atomization Mechanism During the Start of Injection

作　　者：王勇[1] 李国岫[1] 虞育松[1] 丁佳伟[1] 

机构地区：[1]北京交通大学机电学院,北京100044

出　　处：《燃烧科学与技术》2012年第5期441-447,共7页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51076008);中央高校基本科研业务费专项资金资助项目(M11JB00300;M11JB00450)

摘　　要：采用气液两相流大涡模拟(LES)方法,结合VOF模型对高压柴油射流在启喷阶段的雾化过程进行数值求解.LES与实验结果(喷雾结构和贯穿距离)具有较好的一致性.然后结合LES模拟的流场信息(速度场、压力场和亚网格黏度场)对雾化过程进行分析.同时通过对比LES结果、实验结果和线性不稳定理论结果对启喷阶段的雾化机理进行了探讨,并提出了新的喷束结构(比Hiroshi Hattori提出的喷束结构更准确地描述了喷束迎风面结构).最后,研究了环境背压对喷雾结构的影响.研究表明,对于无空泡射流,启喷阶段射流头部迎风面存在的RT不稳定机制分裂的液滴是液滴的主要来源.Large eddy simulation （LES）methodology coupled with volume of fluid （VOF）method was used to study the breakup process of spray atomization during the start of injection （SOI）. Results show that the spray configuration simulated by multiphase LES methodologies was in good agreement with the experimental results. Then the effects of the simulated field results, e.g. velocity field, pressure and subgird viscosity partial distribution, on spray atomization were discussed. After the analysis of the simulated （e.g. LES and linear stability theory＇s model）and experimental results, the mechanisms of spray fragmentation were analyzed. Moreover, a new spray configuration model which can more accurately describe the spray frontal area than that proposed by Hiroshi Hattori, was put forword. Eventually, the effects of ambient back-pressure on spray structure were studied. The results indicated that liquid droplets and fragmentations were mainly produced by RT instability in the frontal area during the SOI for non-cavitation fuel spray.

关 键 词：燃油射流 雾化机理 大涡模拟 喷雾结构 空气背压 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]