Mixing intensification using an acoustic microfluidic device aided with multi-lobed sharp edges under various oscillation boundary conditions

Abstract

This paper examines the performance of a micromixer equipped with acoustically oscillated multi-lobed sharp edges, designed to achieve uniform mixing within the device. Numerical simulations are conducted using the generalized Lagrangian mean (GLM) theory and the convection–diffusion equation, implemented through COMSOL Multiphysics software. Unlike other numerical studies, this paper assesses the impact of oscillation boundary condition on mixing performance. The results demonstrate that oscillating the inlet and sharp-edge boundaries significantly improves localized mixing by inducing dynamic, multidirectional acoustic streaming and intricate vortex patterns. For example, oscillating the sharp-edge and inlet boundaries in the X-direction achieves a mixing index (MI) of 84.93%. In contrast, oscillating the sharp-edge and inlet boundaries in both the X- and Y-directions increases the MI to 97.94% for a two-lobed sharp-edge configuration. The results also reveal that the MI improves with an increase in the number of sharp edges, the applied frequency, and the displacement amplitude. However, it decreases as the background inlet velocity increases.