Simulation Study On The Dynamic Performance Of Piezoelectric Transducer

Compared with other traditional flow meters, gas ultrasonic transducer has outstanding advantages. Wits its high accuracy, wide range ratio, stable and reliable performance, no pressure loss, gas flow meter has a wide future especially in the field of natural gas flow measurement. The gas flow meter with 50mm caliber for middle and lower reaches of natural gas pipeline network in our country should provide good economy and performance. However, foreign countries are monopolies of gas ultrasonic flow meter market. Thus with an increasing demand on gas ultrasonic flow meter in our country, we need to develop these products with our own intellectual property right. The ultrasonic transducer used in flow meter is an important and basic sound-electric energy conversion sensor, whose performance will directly affect the meter’s overall performance. Gas flow meter used to measure natural gas puts forward specific design requirements for its own ultrasonic transducer. So this subject aims to develop a gas ultrasonic transducer suitable for economical gas ultrasonic flow meter.Firstly, this paper carried out the ultrasonic theory and ultrasonic transducer’s design theory. On the basis of practical working conditions, piezoelectric ceramic’s material was selected, and its vibration mode and size were defined. Also according to sound’s propagation and transmission in matching layer, the design specification of matching layer was gained in an ideally matched situation.Secondly, ANSYS transient performance simulation was used to analyze that matching layer’s material, diameter and thickness, backing’s thickness have much influence on ultrasonic transducer’s emission sound pressure, receiving voltage response as well as its central frequency. Simulation model about correlation type transducers was set up on the basis of ANSYS’s piezoelectric coupling and fluid-structure coupling analysis, which can directly show ultrasonic transducer’s working condition in time domain. Besides, transducers’ transient performance under different temperature or pressure of medium gas was discussed.Thirdly, structural design of ultrasonic transducer was carried out, which includes piezoelectric ceramics, matching layer, backing and their parameters. In consideration of its working environment, ultrasonic transducer has its strength and protection structures such as metal protection film of matching layer, metal pressing board and seal structure, which improve its working reliability.Then ultrasonic transducers’ performances were tested. Voltage magnitude and signal-to-noise ratio can meet its working requirements. Admittance Grid can show ultrasonic transducer’s frequency characteristic. Consistence of performance is a guarantee for pairing these transducers. The results of pressure or temperature tests were compared with the simulation conclusion. In practice, high temperature will reduce transducer’s performance.Finally, thesis summarizes the research work of this project, and puts forward some prospects.