Numerical study of concentration fluctuations and stirring effects in a batch reactor

Abstract

The Linear-Eddy Model has been applied to simulations of stirring effects on the decay of concentration fluctuations in the chemical system A → X, 2X → P in a batch reactor. The reactor size and the size of the stirrer are the same as in experiments with the Belousov-Zhabotinskii reaction with oxalic acid in which oscillations appear when the stirring rate is between 50 and 150 rpm but are suppressed above 200 rpm. An interesting coincidence has been found between our simulations and experimental observations. The results support the idea that stirring affects especially rapid chemical reactions with reactants in low concentrations. Simulations show that the combination of concentration fluctuations, turbulent mixing and chemical kinetics may be the key to understanding this stirring effect.