Concentration dependent changes of apparent slip in polymer solution flow

1990 ◽  
Vol 34 (2) ◽  
pp. 223-244 ◽  
Author(s):  
H. Müller‐Mohnssen ◽  
D. Weiss ◽  
A. Tippe
Keyword(s):  
Polymer Solution ◽  
Solution Flow ◽  
Apparent Slip

Drag Reducing Polymer in Helicoidal Flow

1981 ◽  
Vol 103 (4) ◽  
pp. 491-496 ◽  
Author(s):  
J. T. Kuo ◽  
L. S. G. Kovasznay
Keyword(s):  
Drag Reduction ◽  
Polymer Solution ◽  
Ph Value ◽  
Flow Behavior ◽  
Superposition Principle ◽  
Polymer Concentration ◽  
Second Phase ◽  
Additional Parameter ◽  
Solution Flow ◽  
Screw Pump

A novel flow configuration was explored for the study of the behavior of drag reducing polymers. A screw pump consisting of a smooth cylinder and a concentrically placed screw was used to create a strongly three-dimensional but essentially laminar flow. In the first phase of the study, the static pressure head developed by the screw pump was measured as a function of polymer concentration (polyox 10 to 100 ppm in water). A large increase of the developed head was observed that behaved in an analogous manner to drag reduction as far as concentration and straining of the polymer solution was concerned. In the second phase of the study, a new apparatus was constructed and the additional parameter of a superimposed through flow was included and the degree of failure of the superposition principle was established. Sensitivity of the phenomenon to chemicals like HCl, HNO3, and NaOH in the polymer solution was also studied. When the effect of these chemicals on the polymer solution flow behavior was presented in terms of the pH value of the polymer solution, it showed a similar trend to those observed in drag reduction.

Power-law polymer solution flow in a converging annular spinneret: Analytical approximation and numerical computation

AIChE Journal ◽  
2011 ◽  
Vol 58 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Kuo-Lun Tung ◽  
Yu-Ling Li ◽  
Che-Chia Hu ◽  
Yu-Shao Chen
Keyword(s):  
Polymer Solution ◽  
Numerical Computation ◽  
Power Law ◽  
Analytical Approximation ◽  
Solution Flow

Experimental Study on Two-Oscillating Grid Turbulence With Polymer Additives

2015 ◽  
Author(s):  
Yue Wang ◽  
Wei-Hua Cai ◽  
Tong-Zhou Wei ◽  
Lu Wang ◽  
Feng-Chen Li
Keyword(s):  
Polymer Solution ◽  
Viscous Dissipation ◽  
Newtonian Fluid ◽  
Coherent Structures ◽  
Dissipation Rate ◽  
Close Relation ◽  
Space Distribution ◽  
Polymer Additives ◽  
Grid Turbulence ◽  
Solution Flow

In order to investigate the polymer effect on grid turbulence, the experiments study on grid turbulence has been built based on Particle Image Velocimetry. The Newtonian fluid flow and 200ppm polymer solution flow in grid turbulence were carried out at different grid oscillating frequency, such as 5Hz, 7.5Hz, 10Hz and 12.5Hz. The experimental results show that the viscous dissipation rate and vortex vector ωz is smaller and more regular in space distribution in polymer solution case at grid oscillating frequency with 5Hz. It indicates that the existence of polymer additives inhibits enormously the viscous dissipation rate and vortex vector, but this phenomenon can be attenuated with the increase of grid oscillating frequency. From this result, it shows that there exists a critical Reynolds number for the inhibition of polymer effect, which is the same as that in turbulent channel flows with polymers. Then, proper orthogonal decomposition (POD) has been used to extract coherent structures in grid turbulence. It is found that it needs 24 and 4 POD eigenfunctions to examine coherent structure in the Newtonian fluid and the polymer solution cases respectively at grid oscillating frequency with 10Hz. It suggests that the coherent structures can be inhibited due to the existence of polymers so as to the flow field to be more regular. But, with the increase of grid oscillating frequency, the number of POD eigenfunctions for the Newtonian fluid case and the polymer solution case respectively are approaching the same. Through this analysis, it can be also seen that the inhibition effect of polymers is close relation with the grid oscillating frequency.

An elastic sublayer model for drag reduction by dilute solutions of linear macromolecules

1971 ◽  
Vol 45 (3) ◽  
pp. 417-440 ◽  
Author(s):  
P. S. Virk
Keyword(s):  
Drag Reduction ◽  
Polymer Solution ◽  
Viscous Sublayer ◽  
Skeletal Structure ◽  
Mean Velocity ◽  
Solution Flow ◽  
Sublayer Thickness ◽  
Maximum Drag Reduction ◽  
The Difference ◽  
Polymer Species

Further evidence of a universal maximum drag reduction asymptote is presented. In the elastic sublayer model, inferred therefrom, the mean velocity profile during drag reduction is approximated by three zones: the usual viscous sublayer, an elastic sublayer where the mixing-length constant is derived from the maximum drag reduction asymptote, and an outermost region with Newtonian mixinglength constant. Upon integration the model yields a friction factor relation, parametric in elastic sublayer thickness, which properly reproduces the known features of turbulent dilute polymer solution flow. The dependence of elastic sublayer thickness upon flow and polymeric parameters is inferred from experimental data revealing two hitherto unknown relationships: namely that on Prandtl co-ordinates, 1/f½vs. log Re f½ the difference in slope between a polymer solution and solvent is proportional to the square root of molar concentration and to the three-halves power of backbone chain links in the macromolecule. The proportionality constant in the preceding relationship is approximately the same for several different polymer species of carbon-carbon or similar skeletal structure in various thin solvents; there is an indication that this constant further depends upon the product of solvent viscosity times the cube of the effective bond length per chain link of the polymer species. Some recent results regarding the onset of drag reduction are also summarized.

Experimental Study on the Drag-Reducing Characteristics in Two-Oscillating Grid Turbulence With Polymer Additives

2016 ◽  
Author(s):  
Yue Wang ◽  
Weihua Cai ◽  
Tong-zhou Wei ◽  
Feng-chen Li ◽  
Li-ming Yao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Drag Reduction ◽  
Polymer Solution ◽  
Turbulent Kinetic Energy ◽  
Newtonian Fluid ◽  
Reduction Rate ◽  
Grid Turbulence ◽  
Solution Flow ◽  
Oscillating Grid

In this paper, we carried out the experimental study to investigate the polymer effect on two-oscillating grid turbulence based on Particle Image Velocimetry. We chose five different concentrations (25, 50, 100, 150 and 200ppm) of polymer solution flow and the Newtonian fluid flow for comparison at three different grid oscillating frequencies (5, 7.5 and 10Hz). The results showed that comparison with the Newtonian fluid case, the turbulent kinetic energy is much smaller in polymer solution cases. A natural definition for drag reduction rate was proposed based on turbulent kinetic energy. It showed that the maximum drag reduction reaches around 80% and the drag-reducing effect increases as the concentration increases. Finally, proper orthogonal decomposition (POD) was used to extract coherent structures in grid turbulence.

Gap Effects in a Rheometrical Flow of a Hydrophobically Associating Polymer Solution: Apparent Slip or Material Instability?

2000 ◽  
Vol 10 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Thierry Aubry ◽  
Louis Blonce ◽  
Michel Moan
Keyword(s):  
Polymer Solution ◽  
Characteristic Size ◽  
Shear Stresses ◽  
Associative Network ◽  
Parallel Disks ◽  
Apparent Slip ◽  
Torsional Flow ◽  
Associating Polymers ◽  
Dispersing Medium ◽  
Gap Effects

Abstract In this paper, we study gap effects and apparent slip phenomena in a torsional flow of a moderately concentrated hydrophobically modified associative polymer solution.Slip is investigated by varying the gap between concentric parallel disks, and the plate surface roughness.The onset of apparent slip is shown to occur when the associative network is destroyed, and the slip velocity to increase with increased shear stresses in the strong shear-thinning region of the flow curve.The apparent slip phenomenon is shown to be due to the associative character of the polymer solution; it has been attributed to the existence of clusters of associating polymers (microgels),which behave like soft particles in a low viscous dispersing medium once the associative network is destroyed.Apparent slip can be eliminated by using measuring plates with roughness of about 100µm, that is of the order of the characteristic size of the microgels.

K-1221 PIV Measurement of a Drag Reducing Polymer Solution Flow

2001 ◽  
Vol II.01.1 (0) ◽  
pp. 105-106
Author(s):  
Fumihiko Mikami ◽  
Atsushi Sasada ◽  
Nobuhide Nishikawa
Keyword(s):  
Polymer Solution ◽  
Solution Flow ◽  
Piv Measurement ◽  
Drag Reducing Polymer
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