Design of new ultrasonic transducer with two elements for flow rate measurement using ultrasonic Doppler method

Abstract

In this present study, we developed a new two-dimensional velocity profile measurement system by utilizing two-elements ultrasonic transducer with both elements acting as transmitter and receiver. The aim is to obtain two-dimensional velocity information along measurement line and calculate the flow rate. We evaluate the transducer with sound pressure measurement and flow measurement. From the sound pressure measurement, there is one main lobe exist at the center between the elements due to the interference of both waves generated from each element. Therefore two-dimensional velocity measurement is possible. From the flow measurement, we can get two-dimensional velocity profile and calculate the flow rate. We compared the flow rate result with the flow rate reading from the electromagnetic flow meter, and we obtained the error of 4.98% for pipe flow and 10.43% for pipe flow under swirl effect with the measurement range from 8 mm to 50 mm. We used B-spline interpolation with Gaussian fitting to estimate the profile from range 0 mm to 8 mm and finally we were able to obtain full vector profile.