Physicochemical Effects on the Chemohydrodynamic Oscillation by the Surface Tension Variation Driven by A + B → C Reaction

Abstract

The influences of physicochemical parameters on chemohydrodynamic oscillations, driven by surface tension variations due to a bimolecular reaction, are examined numerically. By considering mass, momentum, and chemical species balances across the air–solution interface, we derived interface conditions and incorporated them into the conventional momentum equation, i.e., the Navier–Stokes equation. By considering the reaction rate, the initial reactant ratio, the reactor size, and Marangoni numbers of the reactants and product, we derived some dimensionless physiochemical parameters, and analyzed their effects on the temporal oscillation of the reaction system. Even though the surface tension gradient due to a faster chemical reaction promotes the damped oscillation, the chemical reaction rate plays little role in the onset of oscillation and its period for the fast reaction system. Furthermore, during the initial reaction period, the temporal oscillation of the reaction system is influenced by the physical parameters, i.e., the Marangoni numbers and the initial reactants ratio. However, the effects of these physical parameters become weaker as the reaction progresses.