The optimal aspect ratio of the T-shaped rectangular microchannel mixer to achieve excellent mixing and hydraulic comprehensive performance

Pressure loss and mixing efficiency are the two important performances of the micromixer. In order to achieve the excellent mixing and hydraulic comprehensive performance, the present work theoretically and numerically studied the influences of channel aspect ratio on the dimensionless total pressure loss Delta p*, the outlet mixing efficiency M-out and their combination M-out/Delta p* to characterize the mixing and hydraulic comprehensive performance of the T-shaped rectangular microchannel mixer with uniform cross-sectional shape and constant cross-sectional area. The present work found that Delta p* first decreases and then increases with the increasing aspect ratio; however, the mixing efficiency decreases with the increasing aspect ratio. More important, M-out/Delta p* first increases and then decreases with the increasing channel aspect ratio, which means the existence of an optimal channel aspect ratio for the micromixer to reach best mixing and hydraulic comprehensive performance. Furthermore, the present work investigates the effects of inlet velocity, channel length and channel cross-sectional area on this optimal aspect ratio. It is found that the optimal aspect ratio first decreases and then increases with the increasing inlet velocity, channel length and channel cross-sectional area. In addition, an increasing modified exponent over the pressure loss results in the increasing optimal aspect ratio.