An Accurate and Efficient Look-up Table Equation of State for Two-Phase Compressible Flow Simulations of Carbon Dioxide

This work presents an efficient and accurate method for the calculation of the properties of carbon dioxide. This is motivated by the massive employment of this fluid in the industrial domain, especially in the refrigeration industry through supersonic ejector cycles, and in the CO₂ capture and storage (CCS) industry. A tabulated equation of state (EoS) is developed in the density-internal energy space, based on the Span-Wagner EoS formulation which is the current international reference for computing CO₂ properties. The tabulated EoS is coupled to the Homogeneous Equilibrium Model to calculate properties of the liquid-vapor mixture. To assess the performance of the developed EoS, three configurations are simulated, namely a shock tube, a tube depressurization, and a converging-diverging nozzle. Throughout the comparisons to other EoSs, such as the Peng-Robinson, the Stiffened Gas and the original Span-Wagner EoSs, the high efficiency of the tabulated equation of state is revealed.