Ultrasonic tomographic flowmeter using dual-transducers for the reconstruction of an asymmetric velocity profile

Abstract

Tomographic ultrasonic flow meter (TUF) is a system that is capable of reconstructing the velocity profile and estimating the average flow velocity with better accuracy than the conventional ultrasonic flow meter (USM). Unfortunately, the TUF has a lower temporal resolution due to its need of large number of measurement data from tranduscers. In this work, two pairs of transducer modules, called dual-ultrasonic transducers, are implemented to reduce the required time for data collection. Each pair of the transducers consists of a transmitter and a receiver. This technique can measure the time of flight(TOF) of ultrasonic wave from upstream to downstream, and vice versa, simultaneously. Numerical simulations and experiments are conducted to investigate the performance of the TUF for reconstructing an asymmetric velocity profile. The numerical simulation result shows that the TUF with six pairs of ultrasonic transducers successfully reconstruct a 2D velocity profile that is close to the results obtained by theoretical analysis. The path configuration of six pairs of dual-ultrasonic transducers has been implemented experimentally on a TUF prototype. The experimental results show that the processing time for data acquisition is about 40ms. The velocity profile obtained by TUF is also confirmed with the USM technique, based on the diametrical and mid radius configurations. The results show that the air velocity measured by every path of those configurations is consistent with that obtained by the TUF in the same position. The differences vary from 0.355% to 19.62% and from 0.304% to 14.51% for mid radius and diametral, respectively, even though none of their acoustic path are directly coincide.