Abstract The atomization characteristics of a commercial spillback hydraulic nozzle were investigated in terms of droplet sizes, velocities, trajectories and spray angles. To replicate the fuel spray of a commercial auxiliary marine boiler, an experimental setup was designed and used to atomize water-glycerol solutions with various viscosities. Droplet size, velocity, position and shape were obtained with a novel pulsating LED backlight imaging system that employs a CCD camera to capture pairs of frames with a delay as short as 1 μs from one another. The overall spray characteristics of the nozzle and distributions for droplet size and velocity were examined for the operating conditions currently used in the burner and by varying three parameters: pressure drop, flow rate through the nozzle and liquid viscosity. Results include droplet size and velocity distributions in different spray regions, a description of the influence of each varying parameter on global indexes such as the Sauter Mean Diameter and a comparison with traditional correlations for pressure swirl nozzles.

中文翻译：

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使用脉动 LED 阴影成像的回溢喷嘴表征

摘要 从液滴尺寸、速度、轨迹和喷射角度方面研究了商用回溢式液压喷嘴的雾化特性。为了复制商用辅助船用锅炉的燃料喷雾，设计了一个实验装置并用于雾化具有各种粘度的水-甘油溶液。液滴尺寸、速度、位置和形状是通过一种新颖的脉动 LED 背光成像系统获得的，该系统采用 CCD 相机来捕获帧对，延迟时间短至 1 μs。喷嘴的整体喷雾特性以及液滴尺寸和速度的分布在燃烧器中当前使用的操作条件下通过改变三个参数进行了检查：压降、通过喷嘴的流速和液体粘度。