Use of dynamically adaptive grid techniques for the solution of electrochemical kinetic equations Part 7. Testing of the finite-difference patch-adaptive strategy on example kinetic models with moving reaction fronts, in one-dimensional space geometry

The patch-adaptive strategy described in Part 5 proves to provide correct, fairly efficient, and nearly automatic solutions to three representative ex ample electrochemical kinetic models in one-dimensional space geometry, tha t exhibit difficult-to-resolve moving reaction fronts in the electrolyte, a way from the electrode. The models describe: double potential step experime nts for a simple mechanism of electrochemically generated luminescence, lin ear potential sweep voltammetry for an EE-DISP mechanism with Nernstian cha rge transfers and a reversible homogeneous disproportionation reaction, and linear potential sweep voltammetry for an RRC-initiated electropolymerizat ion reaction scheme. The strategy dynamically creates spatio-temporal grids that adaptively concentrate in the regions of the reaction fronts, without any a priori knowledge about their location. Numerical difficulties. such as electric current oscillations observed with the previously described ada ptive moving grid technique in the case of moving reaction fronts, do not o ccur in the present strategy. However, further work is needed to improve th e performance of the strategy in the cases of reaction fronts associated wi th fast and irreversible second-order homogeneous reactions, for which the computational costs are too large. Improvements are also desirable in the c ase of the simulation of a rapidly moving reaction front occurring in the e lectropolymerization model, for which the strategy tends to provide incorre ct front positions. (C) 2000 Elsevier Science S.A. All rights reserved.