The thesis related to this dataset investigates, for the first time, the tomography-based real-time control of multiphase flows. A gas-liquid axial cyclone separator is used in the experiments, that combine (i) the development of fast tomography algorithms for real-time control applications, (ii) the physics of swirling gas-liquid flows, (iii) the phase distribution dynamics in the axial cyclone, and (iv) the tomography-based real-time control of the phase distribution near the cyclone outlets. This dataset contains experimental data related to: (i) the real-time Electrical Resistance Tomography (ERT) image reconstruction algorithm proposed in the current research to measure cyclone flows in the columnar regime, resulting in phase distribution reconstructions more precise and up to three orders of magnitude faster than traditional ERT algorithms ( Chapter 2 of the thesis); (ii) flow pattern maps of the vertical upward swirling gas-liquid pipe-flow patterns that can be created in axial cyclones for a wide range of …