A new experimental device was developed to observe and measure the dynamic generation of supercritical CO2 (scCO2) in a closed chamber. The temperature and pressure were measured locally using a thin thermocouple and a pressure transducer, respectively. The Rayleigh scattering in the chamber was visualized using a high-speed video camera. The liquid CO2 was heated by a ceramic heater located at the top or bottom of the chamber. Using this new experimental device, the color variation due to Rayleigh scattering was observed. The temperature profile was stable and scCO2 was generated slowly within a few seconds when heating occurred at the top. For heating at the bottom, scCO2 was created faster within 1 s. Additionally, natural convection, turbulence, and a phenomenon resembling boiling were observed. Numerical simulations of the scCO2 creation in a chamber were also performed using the COMSOL Multiphysics application along with the PROPATH package to obtain the thermophysical properties of CO2. The simulation results showed that scCO2 creation for heating at the top was stable due to the gas-like properties of the scCO2 near the heater. For heating at the bottom, the density distribution initially depended on the temperature distribution. However, as natural convection developed, the flow in the chamber was perturbed and the density distribution depended on both the temperature distribution and the density fluctuation caused by the convection vortices. The same tendency was observed in the experimental results. Using PROPATH, the density variation in the scCO2 generation was estimated from the measured temperature and pressure. The P-T diagram and density variation were compared in each experiment.

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