Effect of wall thermal condition on the nonequilibrium condensation of CO2 in supersonic flows

Carbon capture, storage and utilization is currently one of the most powerful measures to minimize carbon emissions, and previous studies have demonstrated the ability of low-temperature flows in nozzles to separate CO2 from gas mixture. To describe the condensation behavior and supersonic flows in the separator, a CFD model including mathematical and numerical methods is proposed. The effect of wall boundaries including adiabatic wall and isothermal wall on condensation behavior is investigated and the temperature range of isothermal boundary is between 250 degrees C and 290 degrees C. The results show that the isothermal and adiabatic boundaries have no obvious impact on the flow structure in the separator, but have an impact on the CO2 condensation behavior. The axial parameters indicate that the wall temperature has no obvious impact on the heat transfer between phases and the normal shock wave, but has an obvious influence on the nucleation and condensation nuclei growth. The radial parameters show that when the wall temperature increases by 40 degrees C, the radial range of nucleation decreases by 13.33%, the condensed CO2 fraction and liquid phase section decreases by 34.48% and 9.61%, respectively.