The real gas effect on the stagnation properties for supercritical carbon dioxide flows

Abstract

This paper presents a comprehensive study on the stagnation properties namely the total pressure and total temperature for supercritical CO2 flows including the methodology, applications and detailed analysis. Due to the high nonlinear real gas effect, it is practically impossible to have explicit expressions between static and its corresponding stagnation properties. The equations of obtaining the real gas stagnation properties as well as their physical meanings related to fluid dynamics need to be reconsidered. In this paper, the stagnation pressure and temperature for sCO2 flows are accurately calculated in a way that implicitly iterated from stagnation enthalpy and entropy without any addendum assumptions. Accordingly, this approach is applied to typical applications that essentially exert stagnation properties. The total pressure and total temperature of typical sCO2 flows in which contain significant real gas characteristics are numerically studied by using our in-house CFD code coupled with real gas models. It is found that the real gas tends to preserve more internal energy than the ideal gas during irreversible flow process especially with the presence of shockwaves. Finally, as a regular indicator of viscous flow loss, the total pressure loss for a sCO2 compressor cascade is evaluated.