Experimental Study On Airflow - Induced Excitation Technology Of Small Vibration Piezoelectric Generator

A small vibration piezoelectric generator is a kind of generator making use of the airflow injected into the tube inside a projectile during flight. It is followed by the excited vibration of the piezoelectric crystal, where the energy of the airflow is tranduced. The generator is efficient, structurally simple and compact. In this thesis, airflow induced vibration of the excited mechanical system for the generator has been studied. Based on our previous research, special strength has been paid onto the flow field performance inside the airflow injected tube and the mechanism of the airflow induced vibration. The frequency pumping structure of the vibration piezoelectric generator has been designed.Based on the research background, key technologies of the airflow induced vibration for the excited mechanical system have been proposed. Based on the application of pneumatic technology to the fuze and the current research status of Hartman resonator, a pumping tube structure for airflow induced piezoelectric resonator has been designed.Then, with computational fluid dynamics, influence of inner curve of the nozzle, resonator length, distance between the nozzle and the resonator, diameter and length of the centre column on the turbulent flow field, especially at the end of the resonator has been analyzed.Finally, in-lab air compressor driving simulation has been performed. The influence of the injected airflow velocity, resonator length, distance between the nozzle and the resonator on the output characteristic of the piezoelectric transducer has been analyzed. The result indicates that all these parameters influence the performance of the generator.The method and result in this study could be provided as a reference for the further studies and designs of the airflow induced vibration generator in the future.