Ultrasonic multi-frequency piezoelectric transducer for generation different sound pressure field patterns

The paper represents numerical and experimental investigation of ultrasonic piezoelectric transducer which operation is based on three different vibration modes. Multi-frequency operation of the transducer allows to obtain sound pressure fields with different patterns, sound fields intensities and frequencies which allows to obtain more flexible and adjustable agglomeration process of fine and ultrafine. Results of numerical investigations have shown that vibration modes of transducer at 25.83 kHz, 34.73 kHz and 52.41 kHz frequencies are suitable for acoustic pressure generation. Moreover, the calculations revealed that at these frequencies sound pressure levels (SPL) reaches up to 142 dB while SPL patterns at different frequencies are different. Experimental investigations have confirmed results of numerical investigations and showed that resonant frequencies of transducer are at 25.65 kHz, 31.1 kHz, 50.8 kHz while SPL values reaches up to 132.5 dB.