A bidirectional valveless piezoelectric micropump with double chambers based on Coanda effect

Micropumps are essential parts of many microfluidic devices. The valveless micropump has the advantage of simple structure and easy manufacture. A bidirectional valveless piezoelectric micropump with double chambers based on Coanda effect has been presented in this paper. The micropump has better performance at low Reynolds number and can change the flow direction by regulating the voltage. The numerical simulations have been done for studying the performance of the micropumps. The results show the volume efficiency of the micropump can be over 50 %. The prototype micropump is fabricated by PMMA with precision machining and the experiment has been carried out to obtain the flow rate and back pressure. As only one piezoelectric actuator is excited and the voltage is set at 500 Vp-p, both the flow rate and back pressure reach the maximum which are 0.26 ml/min and 1.79 kPa, respectively, at the frequency of 10 Hz. As the other piezoelectric actuator is excited and the voltage reach 300 Vp-p, the flow rate and back pressure are 0.408 ml/min and 3.18 kPa, respectively, which are 57 and 78 % larger, respectively, than those at zero voltage.