圆柱超声换能器的负载特性及其电声效率

对圆柱超声换能器在液体中的负载特性进行了研究,推导得出了换能器在液体介质中径向声辐射阻抗,并得出了有载圆柱压电超声换能器的频率方程;探讨了有负载的圆柱换能器输入阻抗随液面半径变化的关系.理论计算表明:随着液面半径的增加,换能器径向辐射阻抗在-∞～∞周期性变化;换能器在液体中会产生谐波共振,谐波数随液面半径的增大而增加.通过实验测量了圆柱换能器在水介质中的谐波共振频率,理论和实验测量结果吻合较好.此外,实验测定了换能器在水介质中的电声效率.

The load characteristic and electroacoustic efficiency of the cylindrical ultrasonic transducer

The load characteristic and electroacoustic efficiency of the cylindrical ultrasonic transducer were studied.The radiation impedance of the transducer in liquid was derived.Based on the equivalent circuit,the frequency equation of the transducer with load was obtained and the relationship between input impedance of the transducer and the radii of liquid surface were analyzed.By numerical calculation,it was showed that the radiation impedance of transducer varied periodically from-∞ to ∞versus the radius of the container.Moreover,harmonic frequencies appeared when the transducer worked in liquid and the number of harmonic resonance frequency increased as the radius of the container increased.The measured harmonic frequencies of the cylindrical transducer in water showed a good agreement with the theoretical frequencies.Moreover,the electroacousitc efficiency of cylindrical transducer was also examined.