Steady-state supercritical fluid flow through both isotropic and anisotropic cylindrical yam packages is modeled as 2-D, axisymmetric flow through porous media. A numerical flow model using a finite-difference method predicts pressure and velocity profiles based on user-defined package geometry, permeability profile, and fluid properties. The use of variable permeability in the model allows simulation of typical package heterogeneities that result from radial variations and relatively denser edges usually associated with package winding. The numerical model is compared with results obtained from analytical expressions for radial flow, axial flow, and 2-D flow in an annulus of isotropic, porous material. The model is then verified using experimental pressure drop measurements for a range of supercritical CO, flows through polyester yam packages. Model predictions show very good agreement with experimental data. (C) 2000 Elsevier Science B.V. All rights reserved.