Abstract: 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．

Key words: Rushton impeller, pitch 4-bladed turbines, stirred tank, laminar model, numerical analysis