压电振子及流体对泵近场噪声的影响

Influence of piezoelectric vibrator and fluid on close noise field of pump

研究了压电振子的弯曲振动形变及振动辐射噪声。首先建立压电泵压电振子振动方程,导出弯曲振动形变函数;提出用微平面活塞振动理论简化压电振子振动模型,推导了近场声压理论计算方程及泵内流体对泵噪声贡献量方程;最后把理论计算结果与试验结果进行比较分析,分别得出在不同频率下压电振子及泵内流体对泵噪声贡献的大小。在输入频率为50 Hz时,泵噪声的理论值为45 dB,实际值为37 dB,泵内流体对泵噪声的影响较大,实际值与理论值的相对误差为21.6%;在输入频率为120 Hz时,泵噪声的理论值为61 dB,实际值为62 dB,泵内流体对泵噪声的影响较小,实际值与理论值的相对误差为1.6%,证明了本研究所提出理论的正确性。

The flexural vibration deformation and vibration radiation noise of piezoelectric vibrator were researched. The vibration equations were built to deduce the flexural vibration deformation functions. Then, the simplified vibration model of piezoelectric vibrator was introduced using vibration theories of micro-plane piston. Also, theoretical equation of sound pressure in close noise field and noise contribution equation of fluid in pump were deduced. Finally, with comparison of the theoretical calculation and experimental testing,the results show that the theoretical noise level of pump is 45 dB and the actual noise level is 37 dB, when the input frequency is 50 Hz. Under this frequency, the fluid in the pump exerts great influence on the pump noise, and the relative error between the testing value and theoretical calculation is 21.6G. The theoretical noise level is 61 dB and the actual noise level is 62 dB, when the input frequency is 120 Hz. In this case, fluid exerts little influence on the pump noise, and the relative error between the testing value and theoretical calculation is 1.6%. It is con eluded that contribution quantities of piezoelectric vibrator and fluid in pump under different frequeneies are obtained,which proves that the theory introduced by this research agrees with the experimen tal results well.