A numerical model for solid-gaseous two-phase flow of CO2 with sublimation in pipes

In the present study, an approach was developed to simulate the flow sublimation of CO2 in pipes. This approach combines a modified two-layer model for solid-gas flow which consists of a dilute phase suspension flow on the upper side of the pipe and a dense phase moving-bed type flow on lower side of the pipe. A heat and mass transfer model is also applied between the phases and layers. Thermal non-equilibrium between the gaseous and solid phase is considered, and the first validation of the model was carried out using experimental data from the literature. The knowledge gained in this study has proven to be helpful in further design and development efforts for a sublimation heat exchanger, which is the primary portion of the next steps of this research.