CFD modelling of drag reduction effects in pipe flows

CFD modeling of drag reduction (DR) by polymer additives dissolving in hydrocarbon was carried out in pipe flows and in a rotating shear viscometer. Two-layer turbulence model describing the damping of turbulence by the DRA molecules in the near-wall regions was applied. The von Karman constant in the near-wall region was used as the model parameter. Extensive measurements of the DR effect for a rotating viscometer were performed at different Reynolds numbers, apparent molar masses and concentrations of DRA. The model with only one fit parameter was able to reproduce the experimental results both in pipe flows and in the rotating viscometer. Experimental results were utilized in relating the model parameter to the relevant physical properties.