Visualization during chemical reacting flow progress in acid-base system

Abstract

In this study, the propagation of the reaction front in the aqueous solutions of acetic acid (CH₃COOH) and sodium hydroxide (NaOH) has been investigated. First of all, we developed the measuring system of refractive index distribution using laser speckle method because of our objective. When the densities of CH₃COOH aq. and NaOH aq. were almost same, the mixing layer of CH₃COOH aq. and sodium acetate (CH₃COONa) aq. with relatively low density could be formed. Then the reaction front had small disturbances and big swell due to Rayleigh-Taylor instability. As time elapsed, the disturbances united and transformed to the large plumes. As the downward flows generated between the plumes, the configuration of the reaction front became more complex.