j karimi sabet - Department of Chemical and Petroleum Engineering sharif university of Technology, Azadi Ave., Tehran
c ghotbi - Department of Chemical and Petroleum Engineering sharif university of Technology, Azadi Ave., Tehran
f farhadpour - Department of Chemical and Petroleum Engineering sharif university of Technology, Azadi Ave., Tehran

Rapid Expansion of Supercritical Solution (RESS) is a promising technique for ultrafine particles formation The size distribution of particles produced by the RESS process is depen s on the operating conditions, as well as on the geometry of the nozzle. In order to have possibility for particle design, it is crucial to conduct more co prehensive studies involving the hydrodynamic of fluid flow and nucleation through the nozzle. In this study, the computational fluid dynamic CFD) modelling of the supercritical ca bon dioxide passing through a capillary nozzle were studied. The CFD simulation is focused on the expansion devise, including the inlet and inside of nozzle. The flow was governed by compressible Navier stokes equation with axisymetry and turbulence was modelled y using RNG k-E model. The supersaturation, nucleation r te of benzoic acid (as a mod l solute) in carbon dioxide was calculated. Also, sensitivity analyses of nozzle shape has been carried out, the re ults show tha on the flow filed and nucleation rate.theses parameter have significant effect

cfd,ress,hydrodynamic,nozzle shape,supersaturation,nucleation rate