An axial scanning system for investigating vertical gas–liquid flows in the slug and bubbly-slug transition regimes

This paper describes a novel axial scanning technique, using a sensor array comprising 64 conductance sensors, which enables estimates to be made of the mean liquid and gas velocities in two phase flows in the slug and bubbly-slug transition regimes. In experiments carried out in an 80 mm diameter vertical pipe, the technique was found to estimate the mean liquid velocity with a systematic error of −3.22% and an additional random error with a standard deviation of 6.37%. The mean gas velocity was estimated with a systematic error of +1.4% and an additional random error with a standard deviation of 4.35%. Since the measurement technique is non-intrusive, it could potentially be used in oil well monitoring applications.