Abstract
In this work, coalescence of gas bubbles is investigated in the presence of gas dissolution and surfactants through a film drainage model. The study on dissolution is carried out for three cases considering low Pe, constant mass flux, and variable mass flux applying for all ranges of Pe. It is seen through the low Pe case that any involved reactions in the system have no noticeable impact on coalescence. The last two cases indicate that gas dissolution delays the coalescence time under specific conditions. While the extent of the dissolution effect for the constant mass flux case depends on the contact time of the two bubbles, the one for the variable mass flux case considers the important impact of the film saturation in addition to the gas solubility and Pe. The effect of dissolution seems to be dependent of the tangential mobility which is strongly influenced by the presence of surfactants. The study is summarized in a map which exhibits the conditions for negligible effect of surfactants and the complete immobilization, depending on the extent of the surface tension changes with the total amount of the surfactants present in the system and how unevenly the surfactants are distributed along the interface. It is found that some realistic cases require other immobilization mechanisms in addition to the Marangoni stresses to reach complete immobilization.
