Numerical investigation of the pulsation frequency of the flow rate effect on the mixing efficiency of the active T-shaped micromixer

Flow patterns and mixing efficiency of fluids with different inlet flow rate pulsation frequencies in T-shaped micromixer were numerically investigated at Reynolds numbers Re = 100 and Re = 180. The flow rate pulsations were set sinusoidal with different frequencies of 0; 1; 10 and 50 Hz. The relative mixing efficiency means the mixing efficiency of active mixer regarding the mixing efficiency of an identical passive mixer without pulsations at the input; it was considered as the main value. The dependences of such value on the pulsation frequencies were obtained. It was found that active micromixers are much more efficient than the passive ones. Herewith, in the engulfment regime, the mixing efficiency increases twofold regarding the passive mixer, and in the region, before the onset of the engulfment regime, the mixing efficiency increases by about 170 times. In addition, it was found that the increase in mixing efficiency is almost independent of the frequency of pulsations.