State of the art in the identification of two-phase transonic flow phenomena in transcritical CO2 ejectors.

The paper presents current developments in both experimental and numerical identification of two-phase flow phenomena in transcritical CO2 ejectors. Neither explicit identification/classification of flow patterns nor determination of velocity field for the CO2 ejector passages, based on experimental methods of flow visualization, has been reported so far. The first trials for determination of spatial fields for the Mach number, pressure, and density inside the CO2 ejector passages, modelled with a validated CFD tool, were reviewed. The influence of the phase transition relaxation on the converging-diverging motive nozzle performance was analysed. Insufficient qualitative and quantitative identification of the phenomena influencing the mass, momentum, and energy transfer was discussed.