Rigid impeller is widely used in stirring mixer. Two mixing regions are usually generated easily: chaotic mixing region and isolated mixing region. Reasonable design of impeller is an effective way to enhance fluid mixing

so that the behavior of chaotic mixing can be regulated. In this study

the signal of pressure fluctuation in the fluid and the chaotic characteristic parameter of Kolmogorov entropy are managed by Labview and Matlab software

and the variation of Kolmogorov entropy with revolving speed in punched impeller system is investigated. The results indicate that the punched impeller system has a negligible influence on Kolmogorov entropy comparing to the traditional rigid impeller system. With punched-flexible impeller

the flow field structure can be regulated efficiently by the co-effect between punch hole and flexible impeller

resulting in excellent chaotic mixing in fluid field with the best effect at 180 r·min-1. Simultaneously

the Kolmogorov entropy of punched-flexible impeller system achieves 0.285

while the value is 0.125 for the traditional rigid impeller system. Obviously

the mixing time in punched-flexible impeller system is superior to that in traditional rigid impeller system

which is decreased by about 17% at revolving speed of 120 r·min-1.