Highly viscous polymeric foam flowing through an orifice

The rapid movement of gas-liquid foams through narrow contractions is commercially challenging and technically important, with wide industrial applications, including the flow and moulding of aerated products, e.g. ice cream and shaving foam, foam-sclerotherapy for varicose veins, and oil-well cementing when foam-cement slurries are pumped into narrow annuli. This study investigates the flow of wet foams with a polymeric liquid phase, which has a high viscosity and complex rheology, using a Multi-Pass Rheometer. The in-situ visualization of foam flowing through an orifice, recorded by high-speed camera, reveals rich and complex behaviour and interaction between bubbles. The bubble behaviour in the polymer melt is qualitatively compared with that observed in a highly viscous Newtonian liquid.