Chemical reaction for mixing studies

We introduce an original chemical reaction between two transparent reactant solutions (fluorescin and potassium ferricyanide), producing a fluorescent product in water (fluorescein). The has tunable kinetics, allowing the quantitative investigation of interplay molecular diffusion kinetics various field topologies. document its sensitivity to ambient pH, temperature, reactants concentrations, etc., we implement it simple reactant-contacting geometries Hele-Shaw cell. resulting reaction-diffusion zones formation rates exhibit either reaction-controlled or diffusion-controlled regimes, as well new “diffusio-chemical” regime which show be inherent early time transient dynamics any bimolecular initially segregated reactants. potential interest this reaction, opening prospects for study reactive mixing, is underlined.Received 22 December 2020Accepted 27 October 2021DOI:https://doi.org/10.1103/PhysRevFluids.6.114501©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasChemical reactionsPattern formationReacting flowsPhysical SystemsReaction systemsTechniquesHele-Shaw cellFluid Dynamics