Drainage and attenuation capacity of particulate aqueous foams

It is well established, nowadays, that if the particles added to aqueous foams are hydrophilic, have proper size and shape they concentrate within the Plateau borders and decrease the liquid drainage. The fact that solid additives can increase the protective performances of a particulate aqueous foam is also well known and even patented. This study bridges the gap between these two different features, which have been investigated to date independently. The experimental finding that small particles (about 45 mu m coal fly ash) slow down temporal and spatial variations of the liquid fraction clarified in the drainage tests was further related to the dynamics of the shock wave propagation in a shock tube. To the best of our knowledge, the results that are reported for the first time can help in better understanding the fundamentals of shock wave/particulate foam interaction.