This work focuses on measuring the velocity profiles of the liquid phase in annular flows by high-speed camera snapshots. This parameter is important for developing flow models and, therefore, improving engineering processes involving heat and mass transfer. This study introduces an image-based technique based on two-dimensional phase correlation to estimate the velocity profiles of liquid films in downward annular gas–liquid flows. High-speed camera images capture the dynamic behavior of disturbance waves and ripples on the liquid film surface. By analyzing sequential images, the method calculates translational offsets, from which velocity profiles are derived. These velocities are input into a mass conservation model to compute the average liquid film thickness, which is then compared with measurements from a conductance sensor. The results show deviations from reference sensor data of approximately 5% for a 26 mm pipe diameter and up to 20% for a 50 mm diameter, indicating reasonable agreement. Additionally, the technique successfully detects and quantifies droplet entrainment from disturbance waves, with deviations within 10% compared to manual measurements.

This work presents a numerical study of performance characteristics and flow dynamics of a centrifugal rotor operating with gas-liquid flow. An Euler-Euler polydispersed model is adopted, which was validated in a previous publication and is used in this work to assess quantities not addressed in the earlier study. An analysis of the rotor performance under two-phase is performed, for which suitable expressions are presented. In particular, an analysis of the rotor head components is carried out including the dynamic head evaluation through the rotor, which is often neglected in most studies. The numerical model is explored further to analyze flow patterns and relevant gas-liquid flow quantities. This includes analysis of the three-dimensional distribution of the gas phase inside the rotor, evaluation of gas-liquid interphase forces, and the effect of the intake gas flow rate on the bubble diameter, gas-liquid relative velocities, and the overall turbulence levels through the rotor. Such analyses, which are usually hard to obtain through experimental methods, are also rarely found in related numerical studies. Thus, this work could bring useful information to help in the understanding of the gas-liquid flow behavior in centrifugal rotors, while also contributing to the progress of numerical solution of this problem.