Abstract: Single-phase flow patterns generated by axial impeller are investigated by 3D Particle Dynamic Analyzer. Mean flow and turbulence intensities are measured for the impeller zone and the bulk regions. The effect of D/T and blade tip angle on flow pattern is studied as well. The measured results show that the flow in impeller zone oscillates periodically at the frequency of blade sweep. The flow patterns generated by different ratios of impeller diameter to tank diameter impeller are approximately the same below impellers,but a small second recirculation loop is formed in the upper part of vessel at the ratio of impeller diameter to tank diameter D/T=0.35.