高剪切分散装置内空化效应的研究

Research on Cavity Effect in High-shear Dispersion Devices

流体机械中的空化现象能带来危害,但也能应用于众多领域。高剪切分散设备中,由于叶轮的高速旋转而在中心产生负压从而出现空化效应。通过剪切流场分析知,当叶轮的转速提高到一定值之后可使空化效应得到显著提升。与常规的摩擦碰撞作用相比,空化瞬间聚集的高能量对极易团聚的纳米材料具有独特的分散作用。为此以纳米二氧化钛为例,进行了高剪切分散的试验,取得了一定的效果。

The cavity phenomenon of fluid machinery is harmful. But sometimes they also can be used in many fields. In high-shear dispersion devices, the impeller＇ s high-speed rotation produces megative pressure in the center and ocurrs cavity effect. Analysis of shear flow field showed that the cavity effect will be improved greatly when impeller rotational speed reaches to the certain value. Comapred to conventional friction and collision action, the high-energy caused by cavitation instant gathering can improve the special dispersion of nano materials greatly.