Simulation of Styrene Polymerization in Arbitrary Cross-Sectional Duct Reactors by Boundary-Fitted Coordinate Transformation Method


, University of Petroleum Industry


The non-orthogonal boundary-fitted coordinate transformation method is applied to the solution of steady three-dimensional conservation equations of mass, momentum, energy and speciescontinuity to obtain the laminar velocity, temperature and concentration fields for simulation of polymerization of styrene in arbitrary cross-sectional duct reactors. Variable physical properties (except for specific-heat), viscous heat dissipation and free-convection effects are considered in modeling while axial diffusion is ignored. The conservation equations originally written in Cartesian coordinates are parabolized in the axial direction and then transformed to the non-orthogonal curvilinear coordinates to handle arbitrary duct geometries. The transformed equations are discretized by the control-volume finite-difference approach in which the convective and diffusive terms are handled by the upwind-difference and central-difference approximation schemes respectively. Results are obtained for eight different geometries. The results show that not a specific geometry is in general superior to conventional circular duct reactors for the highest conversion of the chemical reaction under study, considering also the least pressure-drop in the reactors.