Intensification of mixing-pumping process in a novel active micropump-mixer with maximum efficiency and minimum energy cost: A LBM-RSM approach

Abstract

In the present paper, a double multiple-relaxation-time lattice Boltzmann simulation and response surface optimization are performed to optimize the performance of a novel active micropump-mixer at high-Peclet number flows. The micropump-mixer is comprised of rotationally oscillating rectangular stirrer and two identical square rotors. Effects of three important non-dimensional parameters of the stirrer, including its diameter (DS), maximum velocity (US), and amplitude (K) are investigated on the mean mixing efficiency (εout), time-averaged of the instantaneous dimensionless averaged velocity (Uave), mixing energy cost (mec) and pumping energy cost (pec). All calculations are carried out for the non-dimensional US and K in the range of 0.1-1, and for DS in the range of 0.5−0.9, at fixed Reynolds and Peclet numbers of Re=1 and Pe=10000. Results indicated that εout increases with DS, and especially with K, while it displays a non-monotonic behavior with US. Furthermore, Uave and mec decrease with increasing DS and K. However, Uave is not influenced by US variations, but mec shows a decrease-increase trend with increasing US. The pec increases with increasing of all three parameters. Finally, optimization results indicated that non-dimensional values of 0.5, 0.702 and 1 respectively for Ds, Us and K are optimum values for multiple-response optimization.