Turbulent mixing of concentrated viscoelastic polymer solution: Influence of submerged sparge shape and orientation

Turbulent mixing of concentrated (0.2%) polymer solutions sparged into turbulent flows within a transparent channel was captured using high-speed imaging to understand the complex mixing phenomena. Square and round sparges were investigated at 0 or 180° to the channel flow. At 0°, vortex shedding from square sparge edges enhanced mixing, but the 180° orientation produced better overall mixing. Image analysis gave the first quantification of flow past bluff bodies issuing viscoelastic fluid jets at industrial flow regimes, from which more appropriate turbulence model closures for fluid dynamics modelling of the process may be derived.