In this study, a piezoelectric stack actuator is used to oscillate a piston in a single cylinder pump. The pump is intended to directly supply a hydraulic actuator for motion control, and power output of about 1kW is targeted. Flow rectification is achieved by the use of passive check valves. The valve resonant frequency is found to have a significant effect on output flow. The expected increase in pump flow rate with driving frequency has been confirmed in simulation to hold true in a certain frequency range only. In addition, check valve size and therefore orifice area has to be adequate in order not to prohibitively restrict flow. Valve spring stiffness and valve mass need to be simultaneously optimized for the area of the valve to achieve the highest flow rate.
Calculations indicate that there is a power limitation due to the high current demand and also a high temperature rise for a large continuously operated piezo stack. Thus the piezo pump appears more promising for smaller scale applications, and those that require intermittent power (i.e. a low duty cycle).