Micropump, which controls small volume of fluid, was investigated for application in microfluidic system. In this study, micropump used piezoelectric actuation, and dynamic passive valves (diffuser/nozzle elements). Piezoelectric diffuser/nozzle-based micropump is expected that it is able to response rapidly, consume lower energy, have lower fatigue, and handle fluid mediums independently of its electrical properties. Pumping efficiency is related to rectification efficiency of diffuser/nozzle elements that is decided by shape of diffuser/nozzle elements.
Previous studies on the micropump were tend to investigate with the experiment and focus on the diffuser/nozzle elements. In this study, we observed the micropump system that included the diffuser/nozzle elements and pumping chamber by numerical simulation with shorter time range (one cycle) than experimental. We used time dependent and deforming mesh scheme with boundary conditions of zero static pressure at inlet and outlet.
As the result, when frequency of actuation increase, the pumping rate increase. During supply mode, maximum pumping efficiency was observed at zero deflection. Varying the opening angle of diffuser/nozzle elements, it was found that there are maximum efficiency at small angle, and minimum at large angle. And we also observed the circular flow in pump chamber at supply mode that is expected mixing pumped medium.