The Design Of Airborne Ultrasonic Transducer With A Matching Layer Based On Radial Vibration Of Vibrator

With the steady implementation of the strategy about natural gas,the demand for ultrasonic gas flow meter has been increased sharply.The cost of natural gas infrastructure will be unacceptable if the ultrasonic gas flow meters still rely on importation.Developing a domestic economic ultrasonic gas flow meter,therefore,become necessary.As one of the important components of gas ultrasonic flow meter,the airborne ultrasonic transducer’s performance will directly affect the overall performance of the ultrasonic gas flow meter.At present,there is no ultrasonic transducer that can meet the demand on the ultrasonic gas flow meter on the market,thus it need to be redesigned.Firstly,according to the requirements of ultrasonic gas flow meter for transducer and some theory of the designing of transducer,it has been determined that the vibrator should work in radial vibration mode and be made by material PZT-5H.The dimensional parameters of the vibrator is then primarily designed.According to the design theory of matching layer,the parameters of matching layer under the ideal condition are obtained.After that,the structure of transducer that has the radial vibration mode of vibrator and a matching layer in the front is designed.Secondly,in order to analyze the working state of the transducer and facilitate the optimization of transducer,the modal and harmonious responses near the radial resonance frequency are analyzed by using ANSYS finite element analysis software.The influence of the size parameters of the piezoelectric vibrator and matching layer on the frequency characteristic and directivity of transducer is then analyzed respectively.In addition,the relationship between the sensitivity of the transducer and the size parameters of the matching layer is also examined by using transient analysis of ANSYS.Finally,a few prototypes of the designed transducer have been fabricated and tested.By comparing the results from the prototypes with the result from simulation analysis,the influence of the parameters of matching layer on the impedance curve of the transducer is validated.The frequency response curve is tested,when using the transducer to send and receive ultrasonic.After that,the working frequency and sensitivity of transducer are analyzed by using the test result and the size parameters of the matching layer.Meanwhile,the variation in the sensitivity of transducer with size parameters of the matching layer has been verified.