Turbulent mixing in dilute polymer solutions

Abstract

Addition of polymer molecules to solvents influences the turbulence characteristics and in turn it influences the macromixing and micromixing behaviour in such flows in a profound way. The mixing lengths is pipe flows of dilute polymer solutions are known to be several times larger than those for Newtonian flows. A simple phenomenological model of polymer-turbulence interaction is developed to evaluate the reduction in friction factor and it is then used for analysing mixing in one-dimensional turbulent flows. The extent of mixing in dilute polymer solution is then predicted quantitatively. The limited experimental data available show that the model simulates mixing in flows of Newtonian fluids as well as in mildly viscoelastic drag-reducing fluids very well.