受限空间内气动雾化效果影响因素

Influencing Factors of Pneumatic Atomization Effect in Confined Space

中文关键词:  气动雾化喷嘴  旋向组合  供油压力  下游受限空间  雾化特性  索太尔平均直径

英文关键词:airblast atomizer  swirling combination  fuel supply pressure  downstream confined space  atomization characteristics  Sauter Mean Diameter （SMD）

中文摘要:

      旋流杯气动雾化喷嘴旋向及其下游受限空间会影响喷嘴下游大尺度涡的形态、大小及位置，从而影响燃油液滴在空间 中的分布。针对气动雾化喷嘴下游液滴分布不均匀的问题，采用试验与数值模拟相结合的方法研究了气动雾化喷嘴下游受限空 间及旋流器旋向组合对燃油液滴粒径的影响。结果表明：采用2级反向旋流方案的气动雾化喷嘴在下游受限空间内产生的大尺 度回流对涡对液滴的卷吸、汇聚能力更强，测得的液滴索太尔平均直径（SMD）大于2级同向旋流方案液滴SMD，最大值达到26 μm；气动雾化喷嘴下游空间径向直径由133 mm增加到173 mm，回流对涡从1对增加为2对，液滴沿轴向向上游汇聚的程度增加， 直径为173 mm受限空间内测得的液滴SMD相比于直径为133 mm空间内液滴SMD，随供油压力的不同增大3～5 μm；测量位置与 大尺度涡结构距离越近，大尺度涡对周围液滴卷吸、汇聚作用越强，测量位置液滴SMD越大。

英文摘要:

      The swirling direction of a swirl cup airblast atomizer and its downstream confined space will affect the shape, size, and position of large-scale vortices downstream of the nozzle, thus affecting the distribution of fuel droplets in space. Aiming at the problem of uneven droplet distribution downstream of the airblast atomizer, the influence of the combinations of the downstream confined space of the airblast atomizer and the swirling direction of the swirler on the particle size of the fuel droplet was studied by a combination of experiment and numerical simulation. The results show that the large-scale backflow paired-vortices generated by the airblast atomizer with a two- stage counter-swirl scheme in the downstream confined space has stronger entraining and converging ability to the droplets, and the measured droplet Sauter Mean Diameter (SMD) is larger than that of the two-stage co-swirl scheme, with a maximum value of 26 μm. When the radial diameter of the downstream confined space of the airblast atomizer increases from 133 mm to 173 mm, the backflow paired-vortices increase from one pair to two pairs, the degree of fuel droplets converging upstream along the axial direction increases, and the droplet SMD measured in the confined space with a diameter of 173 mm increases by 3-5 μm with different fuel supply pressures compared to the droplet SMD in the space with a diameter of 133 mm. The closer the distance between the measurement position and the large-scale vortex structure, the stronger the entraining and converging effect of the large-scale vortex on the surrounding droplets, and the larger the SMD of the droplets at the measurement position.