引信振动压电发电机气流致声激励特性研究

为满足引信振动压电发电机的驱动性能要求，解决激励能量关键问题，设计了一个环形喷嘴—共振腔结构的喷注发生器声源。应用计算流体动力学方法，通过仿真模拟解释喷注激发声波致共振腔振动特性；用试验所测的响应电压与仿真获得的共振腔底部声压对比。研究结果表明：共振腔内的声压和轴向质点速度随时间的变化曲线近似于正弦波，相位差为90°，说明了在共振腔内形成了驻波声场；共振腔底部声压幅值和频率较稳定，且幅值较大；压电片的开路响应电压频率与仿真声压频率很接近，从而验证了喷注发生器声源产生纯音的特征。因此，这种根据气流致振原理设计的无活动零件的喷注发生器声源，有利于提高引信振动压电发电机的激励能量。

Study of Drive Characterization of Fuze Vibration Piezoelectric Generator Based on Airflow-induced Sound

In order to satisfy the drive performance of fuze piezoelectric generator and solve the key problem of excitation energy, an annular nozzle-resonator structure is proposed. CFD method is applied to simulate aerodynamically driven acoustic vibration induced by jet in the resonator. And also, the experiment testing response voltage of piezoelectric transducer is compared with the simulating sound pressure at the bottom of resonator. The results show that the curves of sound pressure and axial velocity varying with time are both similar to sine wave, and their phase difference is approximate 90°, which indicates that a standing wave acoustic field is established inside the resonator. Amplitude and frequency of the simulating sound pressure at the bottom of resonator are much stable and have large amplitude. The frequency of the response voltage is close to that of the simulating sound pressure, which verifies that the jet generator source can produce very stable pure tone. Therefore, the designed jet generator sound source, according to the principle of air flow induced vibration, has non moving components, which is beneficial to improve excitation energy of fuze piezoelectric generator.