LAUSR

Ultrasonic flowmeters (UFMs) based on the principle of transit time difference are widely used in process industries. The transit time difference is obtained through analyzing received acoustic signals generated by a couple of transducers located upstream and downstream respectively. The quality of received acoustic signal will directly affect the measurement accuracy of UFM. For this reason, a measurement-calculation coupled approach combining measurement tools and numerical simulation for calculating the acoustic signal of UFM is proposed in this paper. The method can predict the acoustic signals of UFM with different flowrates. First, important boundary condition (vibration velocity on transmitter transducer surface) is measured by measurement tool, which can reduce computational complexity and also avoid modeling transmitter transducers. Second, simulating the wave propagation (difficult to access experimentally) within moving medium by using the measured vibration velocity. Third, obtaining the transfer function of receiver by comparing estimated force acting on the receiver transducer surface with measured voltage signal from receiver, which can avoid modeling receiver transducer. Finally, predicting the received acoustic signal at different flowrates by using the transfer function. The rationality of predicted data was validated by comparing experimental and predicted acoustic signal on receiver transducer at different flowrates. A good agreement between simulated and experimental data was obtained, which means that the working processes of the acoustic signal generated by actual transducers inside UFMs can be accurately predicted based on this method. Analysis of the predicted results will provide good guides and advices to the design of UFMs involving actual application.