液-液循环流化床制取流体冰雾化机理实验

对液-液系统射流雾化机理进行了实验研究.通过改变水的喷射速度和非相溶介质的流速,来研究不同条件对雾化的影响,利用高速摄像仪捕捉各种工况下的雾化结果.采用图像处理与数值计算相结合的方法对雾化结果进行了统计整理,对雾化过程中影响雾化液滴平均粒径、射锥高度以及雾化现象的关键因素进行了探讨,并应用Rosin-Rammler分布函数对液滴粒径分布进行了分析.结果表明:每种工况下的雾化液滴粒径存在着离散性,能很好地符合Rosin-Rammler分布规律;当非相溶介质流速保持不变时,雾化液滴统计平均粒径与射锥高度分别在喷射速度为2.3与 3.5m/s时,达到最大值;而在相同的喷射速度下,改变非相溶介质流速所得雾化结果也完全不同.喷射速度以及周围非相溶介质的流速是影响雾化结果的重要因素,合理选择其值对优化雾化性能及控制雾化过程有着重要的意义.

Experimental study on mechanism of drops formation in liquid-liquid circulating fluidized bed for ice slurry production

The mechanism of jet breakup and subsequent drops formation was studied experimentally.A high-speed CCD(charge coupled device) camera was employed to acquire in real-time the process of drops formation.Crucial factors that strongly influence the mean drop-size,jet length and the appearance of drops formation were investigated systematically by means of image processing and numerical calculation.Further,the Rosin-Rammler function was applied to analyze the drop-size distribution.Final results show that the drop-size distributes non-uniformly even under the same condition and agrees relatively well with the Rosin-Rammler distribution function.When the flow rate of the ambient immiscible liquid maintains invariable,the mean drop-size and the jet length reach the maximum respectively at the jetting-velocity of 2.3 m/s and 3.5 m/s.However,for a constant jetting-velocity,the process of drops formation appears completely different as the flow rate of the immiscible liquid changes.The process of drops formation rests seriously with the jetting-velocity and the flow rate of the immiscible liquid,and the values specified for them play a key role in optimization and control of drops formation.