The spray characteristics of the pressure swirl nozzle are experimentally studied using particle dynamics analysis (PDA) and high-speed photography system in this paper, specifically focusing on the dependence of geometrical dimensions of orifice on the spray SMD, velocity magnitude and droplet distribution, and the spray cone angle. It is indicated that the increase of orifice diameter makes the initial swirling velocity lower and the spray liquid film thicker. When the spray cone is fully expanded, the flow rate of 900 μm orifice diameter nozzle increases by 30–40% and the SMD of 900 μm orifice diameter nozzle increases by 8.5% compared with that of 700 μm orifice diameter nozzle. According to the experimental conditions, the relationship between Re and spray angle was calculated as θ = 29.97*Re^0.087, ignoring the factors that had little influence on spray angle. The decrease of the orifice length makes the distance of gas-medium shearing action shorten so that thinner oil film near wall cannot be formed by the extrusion of air core, leading to the swirling intensity reducing and the suction effect weakened. The spray cone angle of the 450 μm orifice length atomizer is about 5° smaller than the nozzle of 500 μm orifice length, and more small SMD droplets are not sucked, resulting in the distribution range of spray SMD declining.

本文利用粒子动力学分析（PDA）和高速摄影系统对压力旋流喷嘴的喷雾特性进行了实验研究，重点研究了孔口几何尺寸对喷雾SMD、速度大小和液滴分布的依赖性，以及喷雾锥角。结果表明，孔口直径的增大使得初始旋流速度降低，喷雾液膜变厚。当喷雾锥完全展开时，与700μm孔径喷嘴相比，900μm孔径喷嘴的流量增加30%~40%，900μm孔径喷嘴的SMD增加8.5%。根据实验条件，计算出Re与喷雾角度的关系为θ=29.97*Re ^0.087，忽略对喷雾角度影响不大的因素。孔口长度的减小，使气介质剪切作用的距离缩短，无法通过空气芯的挤压在近壁处形成较薄的油膜，导致旋流强度降低，吸入效果减弱。450μm孔口长度雾化器的喷雾锥角比500μm孔口长度的喷嘴小5°左右，更多的小SMD雾滴没有被吸入，导致喷雾SMD的分布范围下降。