Abstract The impaction-pin spray nozzle is widely used in chemical and process industries. To study the atomization characteristics of the impaction-pin nozzle, a high-pressure atomization apparatus was developed and an optical imaging system for the measurement of droplet parameters was proposed. The droplet size and velocity vector were extracted from the shadowgraph images and the influence of liquid pressure drop especially nozzle orifice diameter on atomization was analyzed in detail. Finally, prediction models for Sauter mean diameter were proposed and the atomization efficiency was analyzed. The results indicate that the range of droplet Sauter mean diameter is 8.55 μm ∼ 37.5 μm while arithmetic mean velocity is 0.483 m/s ∼ 1.921 m/s at the pressure drop range of 0.525 MPa ∼ 4.95 MPa for PJ6. For PJ8, the range of diameter is 20.6 μm ∼ 53.9 μm while velocity is 0.746 m/s ∼ 2.879 m/s at the pressure drop range of 0.43 MPa ∼ 3.32 MPa. The size and velocity of atomized droplets both follow the law of logarithmic normal distribution. The droplet diameter is negatively and the velocity is positively related to the pressure drop, while both of the diameter and velocity are positively related to the nozzle orifice diameter. The atomization efficiency declines with the rise of pressure drop and orifice diameter. Besides, empirical correlation models related to gas Weber number and liquid Reynolds number for droplet size and the atomization efficiency were also built accurately. The research provides guides for studies on atomization properties of spray nozzles and their applications.

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基于成像分析的冲击针喷嘴雾化特性实验研究

摘要 冲击销喷嘴广泛应用于化工和加工工业。为研究撞击针式喷嘴的雾化特性，研制了一种高压雾化装置，并提出了一种用于液滴参数测量的光学成像系统。从阴影图图像中提取液滴尺寸和速度矢量，并详细分析了液体压降特别是喷嘴孔口直径对雾化的影响。最后，提出了索特平均直径的预测模型，并对雾化效率进行了分析。结果表明，PJ6 在 0.525 MPa ～ 4.95 MPa 的压降范围内，液滴 Sauter 平均直径范围为 8.55 μm ～ 37.5 μm，算术平均速度为 0.483 m/s ～ 1.921 m/s。对于 PJ8，直径范围为 20.6 μm ∼ 53。9 μm，而速度为 0.746 m/s ∼ 2.879 m/s，压降范围为 0.43 MPa ∼ 3.32 MPa。雾化液滴的大小和速度均遵循对数正态分布规律。液滴直径与压降呈负相关，速度与压降呈正相关，而直径和速度均与喷嘴孔口直径呈正相关。雾化效率随着压降和孔口直径的增加而下降。此外，还准确建立了与气体韦伯数和液体雷诺数有关的液滴尺寸和雾化效率的经验相关模型。该研究为喷嘴雾化特性的研究及其应用提供了指导。雾化液滴的大小和速度均遵循对数正态分布规律。液滴直径与压降呈负相关，速度与压降呈正相关，而直径和速度均与喷嘴孔口直径呈正相关。雾化效率随着压降和孔口直径的增加而下降。此外，还准确建立了与气体韦伯数和液体雷诺数有关的液滴尺寸和雾化效率的经验相关模型。该研究为喷嘴雾化特性的研究及其应用提供了指导。雾化液滴的大小和速度均遵循对数正态分布规律。液滴直径与压降呈负相关，速度与压降呈正相关，而直径和速度均与喷嘴孔口直径呈正相关。雾化效率随着压降和孔口直径的增加而下降。此外，还准确建立了与气体韦伯数和液体雷诺数有关的液滴尺寸和雾化效率的经验相关模型。该研究为喷嘴雾化特性的研究及其应用提供了指导。而直径和速度都与喷嘴孔口直径正相关。雾化效率随着压降和孔口直径的增加而下降。此外，还准确建立了与气体韦伯数和液体雷诺数有关的液滴尺寸和雾化效率的经验相关模型。该研究为喷嘴雾化特性的研究及其应用提供了指导。而直径和速度都与喷嘴孔口直径正相关。雾化效率随着压降和孔口直径的增加而下降。此外，还准确建立了与气体韦伯数和液体雷诺数有关的液滴尺寸和雾化效率的经验相关模型。该研究为喷嘴雾化特性的研究及其应用提供了指导。