Numerical investigation on intensified mixing performance with modified dual impeller

Abstract

Process intensification is important for achieving efficient fluid mixing. In this study, the process intensification mechanism of mixing was investigated based on the evolution of sub-steady flow pattern. The results showed that the modified dual impeller (Mod-DI) could eliminate the isolation zone and symmetry of the flow pattern, which always appears in the traditional dual impeller (Trad-DI) system. Furthermore, the mixing time (tm) and dynamic equilibrium time (tde) of the Mod-DI system were significantly shorter than those of the Trad-DI system, which could be attributed to the enhancement of fluid flow fluctuations caused by the loss of stability of sub-steady flow field. In the presence of baffles, tm and tde could be further reduced. The shortening of time was at the expense of increasing power consumption. Overall, the intensification mechanism of the Mod-DI is mainly since the formation of sub-steady flow field, which enhances the instability of the fluid flow.