摘要
Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines,in-cluding Rushton turbine,concaved blade disk turbine,half elliptical blade disk turbine,and parabolic blade disk turbine.Phase-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in detail.The location,size and strength of vortices were determined by the simplified λ2-criterion and the results showed that the blade shape had great effect on the trailing vortex characteristics.The larger curvature resulted in longer residence time of the vortex at the impeller tip,bigger distance between the upper and lower vortices and longer vortex life,also leads to smaller and stronger vortices.In addition,the turbulent ki-netic energy and turbulent energy dissipation in the discharge flow were determined and discussed.High turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with them.Although restricted to single phase flow,the presented results are essential for reliable de-sign and scale-up of stirred tank with disc turbines.
粒子图象 velocimetry 技术被用来分析后面的旋涡并且阐明他们与在 0.48 m 直径的一辆搅动的坦克的骚乱性质的关系，由四台不同磁盘汽轮机，包括的 Rushton 汽轮机， concaved 片磁盘汽轮机，半椭圆的片磁盘汽轮机，和寓言的片鼓动了磁盘汽轮机。impeller 片附近的平均阶段、解决阶段的流动领域被测量，后面的旋涡的结构详细被学习。旋涡的地点，尺寸和力量被简化 2 标准决定，结果证明片形状在后面的旋涡特征上有大效果。更大的弯曲在 impeller 尖端，在上面、更低的旋涡之间的更大的距离和更长的旋涡生活导致了旋涡的更长的住处时间，也导致更小、更强壮的旋涡。另外，在分泌物流动的狂暴的动能和狂暴的精力驱散坚定、讨论。高狂暴的动能和狂暴的精力驱散区域在上面、更低的旋涡之间被定位并且与他们一起移动了。尽管限制了挑选阶段流动，介绍结果为有圆盘汽轮机的搅动的坦克的可靠设计和按比例增加是必要的。
基金
Supported by the National Natural Science Foundation of China（20776008 20821004 20990224）
the National Basic Research Program of China（2007CB714300）
