循环流化床液液雾化过程转型的实验研究

建立了循环流化床液液雾化的实验装置,对水在非相溶介质中喷射雾化进行了研究。采用高分辨率数码摄像仪实时采集不同工况条件下的雾化形态,对比分析了雾化过程转型现象;通过图像处理与数值计算相结合的方法,对实验结果进行了分析。结果表明,雾化过程与相间相对雷诺数密切相关,在相对雷诺数为1 632时,由鼓泡型转变为连续射流型,而当相对雷诺数增加到1.14×105时,雾化则由连续射流型转变为紊态射流型;在雷诺数大于1.62×105后,液滴粒径急剧减小。在紊态射流形态中,雾化液滴数多且粒径微小,符合液液循环流化床制取流体冰技术对液滴尺度的要求。

Experimental study on form transition of drops formation in liquid-liquid circulating fluidized bed

The experimental apparatus of liquid-liquid circulating fluidized bed for drops formation was built up,by which the mechanism of drops formation of water in another immiscible liquid was investigated systematically.The high-resolution digital CCD(charge coupled device) camera was employed to acquire the process of drops formation in real-time,and the phenomena of form transition were studied based on comparison of the presentation of the photographs.The data extracted from photographs was reduced and analyzed by means of image processing and numerical calculation.The results show that the course of drops formation rests seriously with the relative Reynolds number between the two phases.It takes on three absolutely different developing forms as increasing the relative Reynolds number.The bubbling form of drops formation converts into the continuous jetting form when the Reynolds number is at 1 632,and then into the confused jetting form at 1.14×105.Furthermore,the drop-size decreases as increasing the relative Reynolds number,especially when the Reynolds number exceeds 1.62×105,and decreasing sharply.In the confused jetting form,jet breaks up intensely into a large number of smaller drops,which is perfect in the technique of circulating fluidized bed for ice slurry production in liquid-liquid system.