Testing Method Of Dynamic Performance Of Gas Ultrasonic Transducer

As a kind of non-contact instrument,gas ultrasonic flowmeter has many advantages,such as high precision,low pressure loss,wear-resistance and wide range ratio.Gas ultrasonic flowmeter is used for flow measurement in natural gas,petrochemical industry and civil aviation due to these advantages.Gas ultrasonic transducer plays an important role for the performance of the gas ultrasonic flowmeter,which can realize the conversion of sound and electricity.O n the one hand,the measurement accuracy of the flowmeter is affected by the different performance between the gas ultrasonic transducers.On the other hand,the stability of the flowmeter is also influenced by the variable performance of gas ultrasonic with the changes of temperature and pressure.The consistency of gas ultrasonic transducers is generally evaluated by the steady-state characteristic between transducers,but it is not evaluated for the actual work state.In view of the above problems,the dynamic performance testing system for gas ultrasonic transducer is designed for echo signal sampling.Based on the sampled echo signal,a method for evaluating the consistency of gas ultrasonic transducer is proposed.Firstly,the hardware circuit is designed for echo signal sampling,transit time measurement and serial transmission,which includes transducer drive circuit,signal receiving and processing circuit,echo signal acquisition circuit and RS485 communication circuit.Then,software design mainly includes MSP430 program design,CPLD program and Matlab program.Finally,the Gaussian model of ultrasonic echo and the artificial fish-swarm algorithm are used to obtain the characteristic parameters of echo signal.The consistency of transducer is evaluated by comparing the Euclidean distance between characteristic parameters of the echo signal.The experiment results show the gas ultrasonic flowmeter whose transducer has consistency evaluation is more accurate.The validity of the dynamic performance testing system and the consistency evaluation method of the gas ultrasonic transducer designed in this paper are verified.