摘要
Driven by the goal of lowering the critical Reynolds number for the transition from vortex to engulfment flow in passive micro mixers, this research employs 3-D computational fluid dynamics to analyze the impact of geometric features. Specifically, we examine mixing angles and vortex generator placements within a micro T-mixer framework (100 ×100 μm2 inlet, 200 ×100 μm2 outlet and 3000-μm mixing length). By systematically varying the mixing angle from 0° to 120° at Reynolds numbers of 50, 100 and 150 (within the vortex flow regime), we determine that the 105° angle is the optimal condition for facilitating the transition to engulfment flow. Furthermore, a comprehensive analysis of 24 vortex generator placements at the inlets reveals that a symmetric placement near the mixer corners, with enlarged horizontal offsets, successfully induces engulfment flow at a Reynolds number of 150. Finally, the combined effect of the optimized mixing angle and vortex generator placement results in a substantial increase in engulfment flow and performance index.
•An optimal mixing angle of 105° promotes engulfment flow at relatively low Reynolds numbers.•Symmetric corner-placed vortex generators with large offsets induce engulfment flow and reduce pressure drops.•The combined effect of an optimal mixing angle and vortex generators enhances engulfment flow.•The mechanisms of engulfment flows induced by geometric modifications are elucidated.