A novel vortex mixer actuated by one-shot electricity-free pumps

Effective mixing is vitally important to many microfluidic devices in the areas of biotechnical industries, analytic chemistry and medical industries. However, most micro-mixers require complicated fabrication procedures, possibly inappropriate for practical microfluidic utilization. These mixers generally operate under low Reynolds-number conditions, causing a relatively long reaction time in various biochemical processes. This study presents a novel hemisphere-shaped vortex mixer to rapidly mix two liquids with simple geometric configuration. To simulate mixing behavior, computational analysis is based on the transient three-dimensional conservation equations of mass, momentum and species concentration. The test flow are treated as laminar, incompressible, miscible, uniform-property flows with insignificant gravity and temperature variation effects over the calculation domain. Considering the proposed mixer concurrently actuated by two finger-pressed pumps without electrical power, both experimental and simulation results show an intense swirling eddy generated in the core region of mixing chamber, achieving a mixing index up to 93% in a one-shot mixing event. 2013 Elsevier B.V. All rights reserved.