离心旋流式喷嘴雾化特性实验研究

Research on Atomizing Properities of Centrifugal Swirl Nozzle

目的进一步优化低温多效蒸馏技术中的喷淋布液方式,提高海水淡化换热效率。方法采用马尔文激光粒度分析仪、高速摄像机和翻转水量仪对不同口径的CJ-9型离心旋流式喷嘴进行研究。结果同一口径的喷嘴,随着水流压力的增加,液滴粒径分布的均匀性显著提高。随着水压的增加,同一个喷嘴液体破碎的纹路变密,同时液膜破碎的长度变短,破碎效果越好,雾化性能越好。同一口径的喷嘴,入口压力越大,其边缘流峰值越高,空心化率现象越明显。同一压力下不同口径的喷嘴,口径越大,其形成双波峰的跨度越短;同一口径的喷嘴,入口压力越大,其形成双波峰的跨度越长,其边缘流峰值越高。结论液滴粒径分布的均匀性随着水压的增加或孔径的减小而显著提高,喷淋密度在直径方向上存在两个峰值,运用"峰谷叠加"原理,来满足低温多效蒸发器布液均匀的整体要求。

Objective To optimize the spraying method in LT-MED system and improve the heat exchange efficiency of seawater desalination. Methods Malvern spray droplet analyzer, high-speed camera and auto overturn water meter were used to research CJ-9 centrifugal swirl nozzle of different diameters. Results For nozzles of the same diameter, uniformity of droplet size distribution significantly increased as the flow pressure increased. With the increase of water pressure, the liquid breakage lines of the same nozzle thickened and length of the broken liquid film decreased. The better the crushing effect was, the better atomization performance would be. The higher the inlet pressure was, the higher the peak value of the edge flow and the more obvious the hollowing rate was. For nozzles of different diameters, at the same pressure, the higher the nozzle diameter was, the shorter the span of double-crest formation was. For nozzles of the same diameter, the greater the inlet pressure was, the longer the span of double crest formation was, the higher the peak value of edge flow was. Conclusion The uniformity of droplet size distribution significantly improves with the increase of water pressure or decrease of diameter. Spraying density has two peak values in the direction of diameter. The principle of superposition of ＂peak-valley overlying＂ could be used to meet the overall uniform disrtibution requirements of LT-MED system.