用流动可视化技术研究混合器内研究简报流场及混合效果

引言 不同流体的混合是化工、生物制品、食品工业等工艺过程中一道重要的工序,仅依靠流体在输送过程中的自然湍流扩散不能进行有效的混合,因此必须使用混合器,使液体在短时间内获得均匀的特性,达到满意的混合效果,并使损失的能量较小.不同行业由于介质性能和混合要求不同,相应混合器的结构也不同.通常国内外多采用经验类比法设计混合器,用取样分析法检验混合效果.随着新技术的发展,深入研究流体混合机理对于高效节能混合器的设计具有重要意义.

FLOW FIELD AND MIXING RESULT IN MIXER BY FLOW VISUALIZATION TECHNIQUE

In this paper the flow field in a static mixer is measured by Particle Image Velocimetry (PIV), which belongs to the technique of flow visualization. The vorticity field is obtained from the velocity field. The sequences of particle images are analyzed statistically and the mixing homogeneity degrees are also determined by calculating probability densities. The relation between the mixing result is also related to the state of flow. The experiment show that the mixing is mainly affected by the motion of vortices, not turbulence diffusion.