In this paper, the idea of adding an expansion segment over traditional airblast atomizer is proposed to improve the spray performance. According to the systematic experiments, the Sauter mean diameter, the droplet size distribution, and the droplet axial mean velocity were obtained to evaluate the spray performance. The correlations between spray performance and four geometrical parameters of the expansion segment which include the length, the angle, the throat area, and position of liquid jet are considered. The atomizer operates at atmospheric pressure and temperature, and the air liquid ratio range is from 0.48 to 2.85. The data of the results were measured by Phase Doppler Particle Analyzer. The results show that more uniform droplet size distribution can be achieved with the addition of expansion segment, and the droplet size distribution factor of the case adding the expansion segment is 52.8% bigger than that of the case with no expansion segment. increases as the length and angle of expansion segment increase. The Sauter mean diameter can be reduced by either reducing the length or angle of expansion segment. As for droplet velocity, it is determined that the droplet velocity increases along the radial direction, which is noteworthy because opposite trend is reported for traditional plain-jet atomizers. With an increase of the length, angle, and throat area of the expansion segment, the droplet axial velocity decays.

中文翻译：

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扩展段几何形状对平喷喷气机雾化器雾化影响的实验研究

在本文中，提出了在传统的鼓风雾化器上增加一个扩展段的想法，以改善喷雾性能。根据系统实验，获得了索特平均直径，液滴尺寸分布和液滴轴向平均速度，以评估喷雾性能。考虑了喷雾性能与膨胀段的四个几何参数之间的相关性，这些参数包括长度，角度，喉部面积和液体射流的位置。雾化器在大气压和温度下工作，气液比范围为0.48至2.85。通过相位多普勒粒子分析仪测量结果的数据。结果表明，增加膨胀段可以实现更均匀的液滴尺寸分布，增加扩展部分的案例比没有扩展部分的案例大52.8％。随着扩展段的长度和角度的增加而增加。索特平均直径可以通过减小扩展段的长度或角度来减小。对于液滴速度，确定液滴速度沿径向方向增加，这是值得注意的，因为对于传统的平喷式雾化器报道了相反的趋势。随着膨胀段的长度，角度和喉部面积的增加，液滴的轴向速度衰减。