Research on ultrasonic process fusing tomography for numerical and laboratory imaging in liquid-background two-phase flow

Abstract

Real-time ultrasonic process tomography (UPT) could be suitable for the conditions including various sizes and locations as well as amount of the interesting targets and different pipelines. However, the difficulty in determining flow-pattern segmentation in the back-projection for both transmission mode and reflection mode was not overcome for real-time imaging. This work focused on an ultrasonic process fusing tomography (UPFT) for implementing both reflection-mode and transmission-mode tomography draw support from an 8-channel scanning technique. The behavior of fan-shaped ultrasonic beam propagation and the characteristics of acoustic field in two phases had been studied, by which the tomographic size resolution about UPFT had been analyzed numerically. The resultant impact on reconstructed image quality due to the operation conditions was discussed in detail. Transmitted waves were adopted as a base of imaging, and reflected waves were integrated as supplementary information to execute threshold optimization. To carry out a validation, a digital 8-channel prototype of UPFT was developed for the laboratory investigation of stratified flow with continuous injection of water. It was found that such ultrasonic tomography yielded significant improvements in reconstruction, compared to single-mode imaging merely using transmitted or reflected waves. At the same time, quantitative results showed that the proposed method facilitated automatic and reasonable flow-pattern identification, and the developed system represented a fast data acquisition and processing as well as strong noise resistance capability.