Concentration measurements of bubbles in a water column using an optical tomography system

• Main Authors: Ibrahim, Sallehuddin, Md. Yunus, Mohd. Amri, Green, R. G., Dutton, K.
• Format: Article
• Published: Elsevier 2012
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/33016/; http://dx.doi.org/10.1016/j.isatra.2012.04.010
• Institution: Universiti Teknologi Malaysia

Optical tomography provides a means for the determination of the spatial distribution of materials with different optical density in a volume by non-intrusive means. This paper presents results of concentration measurements of gas bubbles in a water column using an optical tomography system. A hydraulic flow rig is used to generate vertical air–water two-phase flows with controllable bubble flow rate. Two approaches are investigated. The first aims to obtain an average gas concentration at the measurement section, the second aims to obtain a gas distribution profile by using tomographic imaging. A hybrid back-projection algorithm is used to calculate concentration profiles from measured sensor values to provide a tomographic image of the measurement cross-section. The algorithm combines the characteristic of an optical sensor as a hard field sensor and the linear back projection algorithm.