Xie Zhuwei, Zhao Zhongtai, Li Dingfu, Li Fei, Zhang Chaojun, Huang Chen, Xiao Yimin
College of Civil Engineering, Chongqing University, Chongqing 400045, China.
Chongqing Research Institute of China Coal Technology & Engineering Group, Chongqing 400000, China.
Sci Total Environ. 2023 Oct 10;894:164994. doi: 10.1016/j.scitotenv.2023.164994. Epub 2023 Jun 17.
The inadequacy of the existing research in characterizing the atomization performance of the whole atomization field by the local region at nozzle axis hinders the improvement of dust removal performance of a spray system, especially for fan-shaped nozzles with large atomization angle. To solve this inadequacy, 88 measuring points were designed in this study to reveal the spatial distribution characteristics of atomization parameters of a fan-shaped pressure atomization nozzle using a 3D Fiber Phase-Doppler Anemometer. Moreover, the atomization performance and dust removal performance of the whole atomization field under different spray pressures were characterized. The results showed that the spatial distribution of atomization parameters in the axis and radial direction of the nozzle was inhomogeneous. As the axial distance from the nozzle outlet increased, the average droplet size showed a trend of first decreasing and then increasing, the proportion of the droplet of 15-70 μm showed a trend of first increasing and then decreasing, while the average droplet velocity and droplet flux showed a decreasing trend. In addition, the spray orientation was perpendicular to gravity, and the atomization field was parallel to gravity, resulting in a significant difference in the average droplet size between the upper region and the axis. Compared with the upper and lower regions, the atomization effect at the axis was superior, manifested by higher average droplet velocity and droplet flux, indicating that characterizing nozzle atomization performance with atomization parameters at the axis will lead to overestimation. The increase of spray pressure can improve atomization performance and dust removal efficiency to a certain extent, but the improvement effect had a limit. The atomization field can be divided into atomization region, expansion region and contraction region, and the expansion region was considered as an effective dust removal region. These findings provide reference for the design and operation of a spray system.
现有研究通过喷嘴轴线上的局部区域来表征整个雾化场的雾化性能存在不足，这阻碍了喷雾系统除尘性能的提升，尤其是对于雾化角较大的扇形喷嘴。为了解决这一不足，本研究设计了88个测量点，使用三维光纤相位多普勒风速仪揭示扇形压力雾化喷嘴雾化参数的空间分布特征。此外，还表征了不同喷雾压力下整个雾化场的雾化性能和除尘性能。结果表明，喷嘴轴线方向和径向方向上雾化参数的空间分布不均匀。随着距喷嘴出口轴向距离的增加，平均液滴尺寸呈先减小后增大的趋势，15 - 70μm液滴的比例呈先增大后减小的趋势，而平均液滴速度和液滴通量呈减小趋势。此外，喷雾方向垂直于重力方向，雾化场平行于重力方向，导致上部区域和轴线处的平均液滴尺寸存在显著差异。与上部和下部区域相比，轴线处的雾化效果更好，表现为平均液滴速度和液滴通量更高，这表明用轴线处的雾化参数来表征喷嘴雾化性能会导致高估。喷雾压力的增加可以在一定程度上提高雾化性能和除尘效率，但改善效果有限。雾化场可分为雾化区、扩展区和收缩区，扩展区被认为是有效的除尘区域。这些研究结果为喷雾系统的设计和运行提供了参考。
