Antagonistic stirring effects in nonlinear chemical systems, experimental and numerical studies

grantor: University of TorontoA little investigated aspect of stirring effects in nonlinear chemical systems in flow reactors is the appearance of qualitative differences such as shifts of steady states in opposite directions, between feeding modes, i.e. premixing or nonpremixing of the feedstreams. It is demonstrated by numerical simulations and experiments that these antagonistic stirring effects, as we refer to them, exist for characteristic properties of a bimolecular reaction, the bistable bromate-sulfite system and the ferrocyanide oscillator. This phenomena is explained by the different ways in which feedstream mixing, the mixing of reagents, and bulk mixing, the global homogenisation of the fluid, affect reaction rates. Necessary conditions for the appearance of antagonistic stirring effects in a kinetic model are established. It is shown that the presence of incomplete macromixing can introduces qualitative differences with respect to stirring effects due to incomplete micromixing alone. An experimental result was thus ascribed to incomplete macromixing.M.Sc