The investigation of hollow hemisphere-shape actuator

Abstract

In this paper we are investigating two possible excitation methods of how to simultaneously excite two vibration types – longitudinal and radial. The first method – is to glue the PZT element to a specifically prepared surface area of the hemisphere. The second way is to connect the hemisphere to a Langevin type longitudinal transducer. For both cases we did modeling to find eigen frequency as well as harmonic analysis in a lower ultrasonic frequency range (20-30kHz). Impedance- frequency characteristic and mechanical vibration amplitudes are measured around resonant frequency. Comparative tests for both systems are performed using proposed actuators for algae ultra-sonication for bio-fuel production. We have determined the relation of longitudinal and radial waves that are traveling from the excitation source to a hemisphere opposite end. The prototypes of proposed systems are designed and manufactured. Comparative algae destruction results are obtained.