A novel approach for quantitative characterization of aqueous in-situ foam dynamic structure based on fractal theory

Abstract

In this study, a quantitative characterization method of in-situ foam microstructure is proposed based on fractal theory and the captured two dimension(2D) microstructure image for the study of its fractal characteristic, evolution law, sensitivity of temperature and concentration, as well as the relationship between average particle size and fractal dimension of in-situ foam. The results demonstrate that in-situ aqueous foam in the bulk phase exhibits fractal characteristics with a box-counting fractal dimension ranging from 1.4 to 2.0. Distinct from the “exponential” evolution law of conventional foam, in-situ foam displays the “check mark” evolution law, which can be precisely described by two items with clear physical meaning in our proposed fitting model. Additionally, the in-situ foam's evolutionary characteristic exhibits high adaptability towards temperature and foaming agent concentration. Elevated temperatures accelerate coalescence, resulting in shorter effective times, while higher concentrations of foaming agents prolong the overall stability of in-situ foam. Besides, the variation of average particle size of in-situ foam correspond closely with the evolution of fractal dimension under different temperatures and foaming agent concentrations, providing the potential for predicting changes in microstructure of in-situ foam by fractal dimension.