Student Posters Repository

Turbulent multiphase flows are common in a wide number of industrial applications and nature;  dispersions or emulsions of two immiscible phases are frequently found, for example, in the food and chemical processing industry, the extraction and transport of crude oil and oil spills in seas and oceans. In many cases an additional element is often present: surfactants are present as impurities or are added to enhance the process efficiency. Surfactants, also known as surface active agents, are amphiphilic molecules, characterised by polar heads and non-polar tails, which accumulate over the interface between the two phases and locally reduce surface tension of this interface. 

These molecules, even at extremely low concentrations, have a strong effect on the dynamics of the entire multiphase flow: the lower surface tension at the interface enhances breakage and deformation of the interface, thus generating more and smaller droplets. This change in the morphology of the dispersed phase strongly affects the overall efficiency of the process: smaller droplets are more dispersed and the total interfacial area is larger, thus favouring mixing and transfer of mass, energy and species through the interface. Numerical simulations are used to shed light on the physics underlying these extremely complex phenomena.