Determination of bubble velocities in vertical gas-liquid pipe flows using ultrafast X-ray tomography

The development of new two-phase flow CFD models is an important goal for industry and research. Such new CFD models have to be validated with suitable experimental quantitative data with high spatial and temporal resolution. Such data are generated by wide experimental series at the vertical titanium pipe test section of the TOPFLOW test facility. Using ultrafast X-ray tomography, air-water and steam-water experiments at co-current upward and downward flows were performed as soon as counter current flows. These generated data were segmentated and analyzed with in-house codes into quantitative data like gas hold ups, velocity profiles, bubble size distributions or interfacial area densities.
In this publication, different methods for determining bubble velocities are presented. The results are discussed as soon as compared.