Nanoscale Characterization for Improving Turbulent Drag Reduction with Polymers
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Nanoscale Characterization for Improving Turbulent Drag Reduction with Polymers Matthew W. Liberatore, Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 No Stock 10000 ppm Stock 1000 ppm Stock 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 60 ppm Xanthan % D rag R eduction Add 50 mM NaCl In salt free solution, the zero shear rate viscosity scaling with polymer concentration agrees with theory for polyelectrolytes in a good solvent. Three critical concentrations (c*, c e , and c D ) are characterized by changes in scaling. When 50 mM NaCl is added, the scaling is well described by theory for a neutral polymer in a θ–solvent. Further, the addition of NaCl results in dramatic increases in c* (70 ppm to 200 ppm) and c e (400 ppm to 800 ppm) and the disappearance of c D . Turbulent drag reduction experiments using a homogeneous xanthan solution show reductions in drag by up to 37%. However, if an entangled stock solution (10,000 ppm or 1,000 ppm) of xanthan is diluted to the same concentration, the resulting drag reduction is improved by a factor of three. No Salt 50 mM NaCl
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Nanoscale Characterization for Improving Turbulent Drag Reduction with Polymers. Matthew W. Liberatore, Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401. No Salt. 50 mM NaCl. Add 50 mM NaCl. - PowerPoint PPT Presentation
Transcript of Nanoscale Characterization for Improving Turbulent Drag Reduction with Polymers
Nanoscale Characterization for Improving Turbulent Drag Reduction with PolymersMatthew W. Liberatore, Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401
No Stock
10000 ppm Stock
1000 ppm Stock
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
60 ppm Xanthan
% D
rag
Red
uct
ion
Add 50 mM
NaCl
In salt free solution, the zero shear rate viscosity scaling with polymer concentration agrees with theory for polyelectrolytes in a good solvent. Three critical concentrations (c*, ce, and cD) are characterized by changes in scaling. When 50 mM NaCl is added, the scaling is well described by theory for a neutral polymer in a θ–solvent. Further, the addition of NaCl results in dramatic increases in c* (70 ppm to 200 ppm) and ce (400 ppm to 800 ppm) and the disappearance of cD.
Turbulent drag reduction experiments using a homogeneous xanthan solution show reductions in drag by up to 37%. However, if an entangled stock solution (10,000 ppm or 1,000 ppm) of xanthan is diluted to the same concentration, the resulting drag reduction is improved by a factor of three.
No Salt 50 mM NaCl
