Experimental investigation on foam formation through deformable porous media

Foam formation in porous media is a topic of growing scientific and industrial interest due to its range of applications, from daily life consumer products to oil recovery. Despite the work done on foams flowing through complex structures, this field still needs to be fully elucidated. An additional complexity to the problem arises when the porous medium is deformable, a situation which has only been faced from a modeling point of view. To address this, the investigation of foam formation in deformable porous media was conducted using commercial sponges as a deformable porous media system, with special emphasis on the effect of confinement on foam bubble size distribution. Foam was formed by wetting the sponge with an aqueous surfactant solution and then squeezing the sponge either between two glass cover slides or between a plastic net and a cover slide. Results revealed that the latter system allowed the formation of drier foams (i.e., with lower liquid fraction, fL < 0.3), more similar to the ones obtained in dish-washing applications. Also, the effect of sponge type, in terms of material and microstructure, on final foam was considered.