Spatio-temporal patterns are analysed for a wire catalysing an exothermic oscillatory reaction while subject to control of the average temperature. With monotonic reaction kinetics the uncontrolled system admits noisothermal oscillations caused by a slow process of activation and deactivation. The controlled wire undergoes spatial symmetry-breaking and different sections of it oscillate out of phase (or in antiphase) in order to maintain the set-point. Nonmonotonic kinetics, due to reactant inhibition for example, induce nonisothermal oscillations in the absence of control while the controlled system may admit truly isothermal oscillations. Even more complex patterns occur when the system admits multiplicity of oscillatory and stable states. This analysis demonstrates again the falsification of kinetics induced by controlling an unstable system. It invalidates the conclusion that the origin of oscillations in controlled catalytic wires is purely kinetic. Similar patterns were observed in an electrochemical reaction subject to a constant current.
|Number of pages||9|
|Journal||Chemical Engineering Science|
|State||Published - 1989|