APPLICATION OF PIEZOELECTRIC FILM IN CAVITATION RESEARCH

A research program was conducted at the St, Anthony Falls Laboratory t o investigate impulse pressures caused by the collapse of transient ca vitation bubbles. The impulsive pressures associated with vibratory as well as hydrodynamic cavitation were measured. Both a stationary spec imen subjected to vibratory cavitation and a hydrofoil of NACA 0015 se ction were instrumented with custom-made pressure transducers using po lyvinylidene fluoride (PVDF) piezoelectric polymer film. These transdu cers provided in situ measurement of impulse pressures. A practical ap plication of this measurement technique was demonstrated in testing th e viability of air injection as a means of mitigating cavitation erosi on. The high sensitivity, minimal thickness, high frequency response, high spatial resolution, and low cost of the piezoelectric transducers point to their applicability in a wide range of field measurements.