ABSTRACT

Pressure swirl nozzles are widely applied in various mineral industries, and their excellent spray performances have been found to be directly related to dust removal results. In this study, in order to examine the influencing effects of the swirl intensity levels of pressure swirl nozzles on atomization characteristics and dust-reduction efficiency, five spiral guide grooves were added for the purpose of improving the quality of the atomization and dust control. The swirl intensities of pressure swirl nozzles were first theoretically investigated using the established models. The effects of the swirl intensities on the atomization angles and distributions of the atomization sizes were comparatively studied using theoretical calculations, numerical simulations, and experimental methods. A dynamic wind tunnel was built in order to conduct dust-reduction experiments with different swirl intensities. The proximate and ultimate analysis results and the sizes of the coal samples were characterized, and the mechanism of the dust reduction was summarized. The results demonstrated that the applications of spiral guide grooves improved the atomization angles and coverage areas by up to 98.8° and 73%, respectively. At the same time, the enhancements of the swirl intensities were observed to reduce the uniformity index of the distribution sizes,` which significantly decreased the Sauter mean diameter (SMD) from 101.3 μm to 22.1 μm. The atomization results revealed that the increasing of the stagger angles benefited the larger atomization angles and smaller SMD. In addition, the proposed theoretical model had achieved better prediction accuracy. Also, the high atomization quality had obviously improved the dust-reduction ability of the pressure swirl nozzles, with the efficiency of total dust and respirable dust removeable increased by approximately 11.23% and 9.33%, respectively.

摘要

压力旋流喷嘴广泛应用于各种矿产行业，其优良的喷雾性能已被发现直接关系到除尘效果。本研究为考察压力旋流喷嘴旋流强度等级对雾化特性和降尘效率的影响，增加了5条螺旋导槽，以提高雾化和降尘质量。首先使用建立的模型从理论上研究了压力旋流喷嘴的旋流强度。使用理论计算、数值模拟和实验方法比较研究了旋流强度对雾化角度和雾化尺寸分布的影响。建立了动态​​风洞，以进行不同旋流强度的降尘实验。表征了煤样的近、终分析结果和粒度，总结了降尘机理。结果表明，螺旋导槽的应用使雾化角度和覆盖面积分别提高了98.8°和73%。同时，观察到涡流强度的增强降低了分布尺寸的均匀性指数，这使 Sauter 平均直径 (SMD) 从 101.3 μm 显着降低到 22.1 μm。雾化结果表明，交错角的增加有利于较大的雾化角和较小的SMD。此外，提出的理论模型取得了较好的预测精度。此外，高雾化质量明显提高了压力旋流喷嘴的除尘能力，总除尘效率和可吸入除尘效率分别提高了约11.23%和9.33%。