Numerical study of the effects of injector needle movement and the nozzle inclination angle on the internal fluid flow and spray structure of a group-hole nozzle layout
Numerical study of the effects of injector needle movement and the nozzle inclination angle on the internal fluid flow and spray structure of a group-hole nozzle layout
复制标题
DOI：
10.1016/j.apm.2015.04.032
复制
发表时间：
2015-12
影响因子：
5
通讯作者：
H. Taghavifar;M. T. Shervani-Tabar;M. Abbasalizadeh
中科院分区：
文献类型：
--
作者：
H. Taghavifar;M. T. Shervani-Tabar;M. Abbasalizadeh
在这项研究中，我们探讨了喷嘴喷孔倾角变化和针头往复运动时，喷雾流动特性的微观变化。在喷嘴倾角分别为10°、15°和30°的情况下，测量了0.01、0.25和0.24 mm三种针尖模式下的体积分数和粘度分布。以不同的针头位置和喷嘴夹角为目标变量，确定了液体粘度这两个关键参数(在液囊体积和喷嘴中发展)与喷嘴内的体积含汽率与喷雾特性和当量比之间的关系。结果表明，夹角越小，空化程度越低的喷嘴粘度越大，而倾角越大，气泡体积段的粘度幅度越大，喷嘴内的粘度越小，空化程度越高。倾角为15°时粘度最低，有利于喷雾雾化过程中的一次破碎。喷嘴倾角为15°时，喷雾分散性最好，这主要是由于喷嘴具有较高的空化程度和较低的空间粘度分布。模型与实验数据的比较表明，基于数值模拟的喷雾结构在穿透深度和液滴直径方面是有效的。
In this study, we explored the spray behavior as a result of microscopic variations in the flow characteristics when the nozzle hole inclination angle was varied and the needle reciprocated. The volume fraction and viscosity contours were investigated at three needle modes of 0.01, 0.25, and 0.24 mm using three nozzle inclination angles of 10°, 15°, and 30°. We determined the relationship between the two key parameters of liquid viscosity (which developed in the sac-volume and nozzles) and volume vapor fraction in the injector with the spray characteristics and the equivalence ratio by considering different needle positions and inter-nozzle angles as objective variables. It was found that a lower included angle led to higher viscosity development in nozzles with low cavitation formation, whereas increasing the inclination angle increased the viscosity amplitude in the sac-volume section and decreased the viscosity in the nozzles, as well as yielding more cavitation formation along the nozzles. The lowest viscosity was obtained with an inclination angle of 15°, which may facilitate the primary breakup process during spray atomization. The highest spray dispersion was achieved with a nozzle angle of 15°, which was due mostly to higher cavitation and a lower spatial viscosity distribution. Comparisons of the model and experimental data demonstrated the validity of the predicted spray structures based on simulations in terms of penetration and the droplet diameter.