PZT bimorph actuated atomizer based on higher order harmonic resonance and reduced operating pressure

This paper presents the design, fabrication and testing of a PZT bimorph actuated atomizer. The atomizer with the size of 43 mm × 37 mm × 7 mm is composed of a PZT bimorph actuator, which is sandwiched by top and bottom flow channel plates and cover shields. The micronozzle plate is attached onto the top cover shield. UV laser machining and micro electrical discharge machining (μEDM) are applied to fabricate the micronozzles with different geometry. The experimental results indicate that we can justify the frequency response of flow rate by acoustic pressure analysis. The peak flow rates occur at higher order resonances, and the operating pressure is less than 0.1 MPa, which is much lower than that of existing atomizers. Also, the influence of flow rate by changing the distance between the PZT bimorph and the nozzle plate, as well as the flat plate on the bottom cover shield are discussed. The maximum flow rate of 8 ml/min is obtained by using the μEDM-made micronozzle plate, when the atomizer is driven with square pulses at 7 kHz with 50% duty cycle and 27 V peak-to-peak.