In this study, polyethylene oxides were used as a drag reducing additive. The effect of the concentration and molecular weight of the polymer on the level of drag reduction was examined using, 4 molecular weights (2 ร 10 5 , 4ร10 5 , 9ร10 5 and, 4 ร 10 6 ) and 4 concentrations (1, 5, 10 and, 20 wppm
Reynolds-averaged modeling of polymer drag reduction in turbulent flows
โ Scribed by Gianluca Iaccarino; Eric S.G. Shaqfeh; Yves Dubief
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 678 KB
- Volume
- 165
- Category
- Article
- ISSN
- 0377-0257
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โฆ Synopsis
A novel eddy viscosity model for predicting friction drag reduction induced by polymers in turbulent wall-bounded flows is presented. The approach is based on the elliptic relaxation model modified to account for the modified Reynolds-stress equilibrium established by the presence of elastic polymer chains in the fluid. The increased wall damping of the turbulent fluctuations is obtained by modifying the pressure-strain redistribution term. Polymer solutions are represented using the Finite Extensibility Non-linear elastic FENE-P dumbbell model; only one transport equation for the elongation of the polymer chains is considered. The model reproduces the level of drag reduction observed over a wide range of rheological parameters. In addition, both the mean velocity and the turbulent fluctuations are predicted with good accuracy. The approach is computationally attractive because of its limited increase in computational cost in comparison with its Newtonian counterpart.
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## Abstract In order to investigate the effects of injection position on drag reduction as well as further the effects of polymer additives on turbulent structures, LDA measurements of turbulent pipe flows were conducted. The results show that the amount of drag reduction grows with the increase of