Enhancing Jet Velocity and Power Conversion Efficiency of Piezoelectric Synthetic Jet Actuators

The present work discusses an experimental investigation into the effect of piezoceramic employed to drive a synthetic jet actuator into a quiescent flow. The electromechanical coupling ratio of polycrystalline piezoceramics, lead zirconate-titanate 5A/5H (PZT-5A/5H), conventionally used in synthetic jet actuators, is inherently low. Therefore, this study aims to investigate using more electromechanically efficient piezoceramics, such as single-crystal, lead magnesium niobate-lead titanate (PMN-PT). In addition, two different orifice-diaphragm configurations of synthetic jet actuators, opposite and adjacent, are tested. It is identified that PMN-PT piezoceramic promotes three times higher transverse diaphragm displacement and two times more peak jet velocity compared to the PZT-5A piezoelectric actuator for the same input diaphragm voltage. A peak exit jet velocity of 99.5 m.s(-1) was obtained at 40 V of peak supply voltage, which can be classified as a low voltage supply compared to other studies in the literature that obtained similar exit jet velocity. Also, a power conversion efficiency of 72% was achieved, corresponding to the Helmholtz resonance frequency. A new figure-of-merit, momentum coefficient per power consumption, is defined to evaluate the potential impact for full-scale implementation. A state-of-the-art value of 0.09 MW-1 is achieved.