Mass Transfer from a Single Spherical Bubble with the Presence of Chemical Reaction - the Effect of Interface Contamination at Low Reynolds Number

A. Dani, A. Cockx, and P. Guiraud
Ingénierie des Systèmes Biologiques et des Procédés, CNRS, INRA, INSA, Toulouse, France

The objective of this work is to compute the mass transfer with chemical reaction (first order reaction) from a single spherical bubble at a low Reynolds number by Direct Numerical Simulation.

Firstly, the contamination of the bubble's surface by the surfactants is considered, since this can reduce the slip velocity at the interface. The stagnant cap model is used to represent these phenomena and to simulate the influence on hydrodynamics and on mass transfer.

Corresponding transport equations are solved with COMSOL and characterized by the Reynolds numbers and the Schmidt numbers. Secondly, the reaction rate is considered for three chemical reaction types (slow, intermediate and rapid) which can be characterized by the Damköhler number.