Two dimensional simulation of rapid expansion of supercritical carbon dioxide

Abstract

The expansion of supercritical fluid solution through a nozzle is a key step for producing fine particles. It makes use of the density change of a fluid from its supercritical state to its gaseous state due to expansion to lower pressure environment. Simulation of rapid expansion of supercritical carbon dioxide requires a set of basic equations of fluid flow field and thermodynamic properties of carbon dioxide from suitable equation of state (EOS). From investigation, it was found that Soave-Redlich-Kwong EOS incorporated with the compressibility factor of carbon dioxide is suitable for estimating of the carbon dioxide thermodynamic properties. The explicit finite-difference and implicit finite-different methods are employed to solve two-dimensional Euler equations for fluid flow field. The calculation results shown that the inlet temperature and inlet pressure gave impact effects on the predicted temperature of flowing fluid passed through the nozzle and for inlet velocity, it could be seen that it rarely gave effect on the predicted temperature of fluid.