A systematic analysis of foam drainage: Experiment and model

Foam drainage describes the flow of a liquid through a foam, driven by gravity and capillarity. This is an important factor for foam stability, and thus of great relevance to many sectors including the oil and gas industries. We are proposing a generalized version of the drainage equation along with an exponential equation to predict the foam life at the later time. The models yield the foam height values as a function of time. It was observed that in early times foam volume, V(t), varies linearly with time and that at later times, it displays power or exponential asymptotes with the exponents depending on the dissipation mechanism. The models were tested through foam experiments in static conditions where the ascending and descending foam heights were monitored as a function of time. Conventional and nanoparticle fortified foams stability under static conditions were tested up to 115 °C and 2.8 MPa. Furthermore, the effect of nanoparticle concentration and different surfactants on foam drainage rate were investigated systematically. Subsequently, measurements were fitted to the empirical expressions. The model coefficients relate to film properties, which vary with pressure, temperature and chemical composition.