旋转盘式雾化雾滴粒径分布实验研究(英文)

Experimental Investigation of Spray Droplet Size Distribution Using a Spinning Disk Atomizer

旋转雾化盘是喷雾干燥系统中的重要部件,但是文献很少涉及到关于这类雾化器产生的雾滴粒径的分布和变化情况。采用一个工业化的2 000 t/a生产可再分散性乳胶粉的雾化机作为模型雾化器,该雾化器最大处理量为2 000 kg/h。实验的雾化盘直径是180 mm,盘上有24个通道,激光粒径分析仪用于实测雾化器产生的雾滴粒径分布。采用变频器控制转速在10 000～16 000 r/min间变化。喷雾干燥后粉体的平均粒径为72μm,比雾化盘产生的雾滴平均粒径92μm小,同时喷雾干燥后最大粉体直径比雾化盘产生雾滴直径小,表明喷雾干燥过程中存在着雾滴间团聚效应。

Spinning disk atomizer is a key part in many spray drying systems.Few works exist in the literatures dealing with size distribution and changes of the droplets produced by such a type of atomizer.In this work,a model atomizer is used to spray-dry a re-dispersible glue emulsion on an industrial scale production 2 000 t/a.The maximum spray capacity of such an atomizer is 2 000 kg/h.The disk tested has a diameter of 180 mm and 24 channels.A laser analyzer was used to measure the droplet size distribution of sprays produced by the spinning disk atomizer.The effects of the disk rotating speed on water droplet size distribution were investigated.The rotating speed of the disk was varied from 16 000 to 10 000 r/min using a frequency-inverter.In order to investigate the change of droplet size to dried particle size from the spray dryer,the droplet size distribution of the re-dispersible glue emulsion and the dried particle size distribution produced were measured.The results show that the mean size was reduced from 92 μm of droplets to 72 μm of dried particles.It was also observed that the maximum dried particle size was larger than that of droplets due to droplet and particle agglomeration taking place within the spray drying chamber.