SOLVING THE MATHEMATICAL-MODEL OF THE REA CTORS - HAVING THE CATALYSTDEPOSITED AT THE WALL AND AXIAL-FLOW, USING THE MULTIGRADE METHOD

This article presents the multigrid method application to solving the mathematical model equations for a porous catalyst wall reactor with a xial flow. The considered mathematical model made up of a non-linear e quations for the solid phase and partial derivativies diffusion-reacti on and a linear, first order, ordinary differential equations system f or fluid phase is the one proposed by Mihail and Teodorescu (1). The d escritization method employed is the centered finite differences. The non-lineary algebric system got by descritization is solved with the n on-linear, multigrid algorithm (FAS variant [2]) The multigrid, intera tion components are: V cycle with 2+1 smoothings on each level, full w eight restriction, bilinear interpollation prolongation; Gauss-Seidel relaxation method (lines variant). The maximum convergence rare was go l when the fluid-phase variables (corresponding to the ordinary differ ential equations system) are not modified by the coarse grid correctio n. All simulations were done on a wide range of parameters variation, avoiding the steady state multiplicity area [3].