Design and Experimental Verification on Characteristics of Valve-Less Piezoelectric Pump Effected by Valve Hole Spacing

Valve-less piezoelectric pumps possess the advantages of simple structure and absence of electromagnetic interference, which has accordingly drawn widespread attention. In this paper, in order to improve the performance of valve-less piezoelectric pumps, various kinds of the prototypes had been designed and fabricated to discover the relationship between the performance and the structural parameters of valve hole spacing. The prototype is comprised of a piezoelectric actuator and a pump chamber through a conical tube that connects the pump chamber with the buffer chamber. First, the flow characteristics of the valve-less pump were performed by using COMSOL Multiphysics. According to the simulation result, the decline of flow velocity around the valve holes on the side far from the center of the pump chamber may be the reasons for the performance degradation. Second, the effect of valve hole spacing on the prototype was investigated with respect to several parameters, such as the chamber height and cone angle. The experimental results indicated that the valve-less piezoelectric pump output flowrate can be improved by reducing spacing valve hole spacing. A maximum flowrate of 8.43mL/min was achieved at valve hole spacing of 3 mm, which is 13.6% and 47.1% higher than that at 15 mm and 25 mm, respectively. We finally verify the feasibility of improving the capacity of valve-less piezoelectric pumps by reducing valve hole spacing.