直叶涡轮及斜四叶桨搅拌槽层流流场的数值分析

NUMERICAL ANALYSIS OF LAMINAR FLOW FIELD IN A STIRRED TANK WITH A RUSHTON IMPELLER AND PITCH 4-BLADED TURBINES

采用计算流体力学(CFD)方法,对直叶圆盘涡轮桨(Rushton)和斜四叶桨(PBT)搅拌槽流场进行研究。利用Laminar层流模型对其在甘油中产生的流场进行数值计算,得到四种形式的搅拌桨以恒定转速200r/min在搅拌槽内转动时所产生的流场结构,对比分析轴向、径向和切向的速度矢量图、速度云图以及速度分布曲线,比较所需的搅拌功率。结果表明:Rushton桨的搅拌效果优于PBT桨,但能量损耗较高;不同倾角的PBT桨具有类似的流动特性。

Computational fluid dynamics （CFD） method was applied to the study of flow field in stirred tank with a Rushton impeller and pitch 4 bladed turbines. The laminar model was employed to simulate the flow field of stirred tank with glycerin fluid, and the flow structure in a stirred tank with four different impellers rotating at constant speed of 200 r/min was obtained. By comparing the velocity vector plots,velocity contours and velocity distribution curves in the directions of axial, radial and tangent,it was found that the stirring effect of Rushton impeller was better than that of pitch 4-bladed turbines, however,high power consumption was accompanied according to the calculated values of required power. The flow characteristics of the pitch 4 bladed turbines with various blade pitch angles were similar.