Online monitoring of transit-time ultrasonic flowmeters based on fusion of optical observation

It is well-known that transit-time ultrasonic flowmeters (TTUF) are unsuitable for bubble-contained flows. This paper presents a new online monitoring method based on optical observation, which monitors the functionality of the TTUF in the presence of bubbles in the fluid. The method avoids the unnecessary Emergency Shutdowns (ESD) due to bubble presence in the fluid by bubble detection. The proposed method accomplishes bubble identification through a combination of image processing and wavelet analysis. In addition, a new method is proposed which estimates single bubble size in horizontal pipes using a data fusion approach.