scholarly journals Universality in coalescence of polymeric fluids

Soft Matter ◽  
2020 ◽  
Vol 16 (48) ◽  
pp. 10921-10927
Author(s):  
Sarath Chandra Varma ◽  
Aniruddha Saha ◽  
Siddhartha Mukherjee ◽  
Aditya Bandopadhyay ◽  
Aloke Kumar ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Polymer Concentration ◽  
Ohnesorge Number ◽  
Polymeric Fluids

Unification of coalescence dynamics for polymeric fluids through relaxation time λ, Ohnesorge number Oh, and polymer concentration c.

scholarly journals Breakup Dynamics of Semi-dilute Polymer Solutions in a Microfluidic Flow-focusing Device

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 406
Author(s):  
Chun-Dong Xue ◽  
Xiao-Dong Chen ◽  
Yong-Jiang Li ◽  
Guo-Qing Hu ◽  
Tun Cao ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Polymer Solutions ◽  
Newtonian Fluids ◽  
Droplet Microfluidics ◽  
Droplet Generation ◽  
Flow Focusing ◽  
Polymeric Fluids ◽  
Practical Applications ◽  
Dilute Polymer Solutions ◽  
Microfluidic Flow

Droplet microfluidics involving non-Newtonian fluids is of great importance in both fundamental mechanisms and practical applications. In the present study, breakup dynamics in droplet generation of semi-dilute polymer solutions in a microfluidic flow-focusing device were experimentally investigated. We found that the filament thinning experiences a transition from a flow-driven to a capillary-driven regime, analogous to that of purely elastic fluids, while the highly elevated viscosity and complex network structures in the semi-dilute polymer solutions induce the breakup stages with a smaller power-law exponent and extensional relaxation time. It is elucidated that the elevated viscosity of the semi-dilute solution decelerates filament thinning in the flow-driven regime and the incomplete stretch of polymer molecules results in the smaller extensional relaxation time in the capillary-driven regime. These results extend the understanding of breakup dynamics in droplet generation of non-Newtonian fluids and provide guidance for microfluidic synthesis applications involving dense polymeric fluids.

Rheological and Hydraulic Properties of Drilling, Completion, and Stimulation Fluids in Straight and Coiled Tubings

2002 ◽  
Author(s):  
Y. Zhou ◽  
S. N. Shah
Keyword(s):  
Drag Reduction ◽  
Guar Gum ◽  
Polymer Concentration ◽  
Hydroxyethyl Cellulose ◽  
Test Facility ◽  
Drilling Mud ◽  
Polymeric Fluids ◽  
Pressure Losses ◽  
Coiled Tubing ◽  
Friction Pressure

The rheological properties and friction pressure losses of several fluids that are most commonly used as well drilling, completion, and stimulation fluids have been investigated experimentally. These fluids include polymeric fluids – Xanthan gum, partially hydrolyzed polyacrylamide (PHPA), guar gum, and hydroxyethyl cellulose (HEC), bentonite drilling mud, oil-based drilling mud, and guar-based fracturing slurries. Rheological measurements using a Bohlin CS 50 rheometer and a model 35 Fann viscometer showed that these fluids exhibit shear thinning and thermal thinning behavior except the bentonite drilling mud whose viscosity increased as the temperature was raised. Flow experiments using a full-scale coiled tubing test facility showed that the friction pressure loss in coiled tubing is significantly higher than in straight tubing. Since the polymeric fluids displayed drag reducing property, their drag reduction behavior in straight and coiled tubings was analyzed and compared. It was found that the drag reduction (DR) in coiled tubing is much lower than that in straight tubing. Plots of drag reduction vs. generalized Reynolds number indicate that the drag reduction in coiled tubing was not affected by polymer concentration as much as in straight tubing. The onsets of turbulence and drag reduction in coiled tubing were significantly delayed as compared with straight tubing. The effect of solids content on the friction pressure losses in coiled tubing is also briefly discussed.

Predicting Drag Reduction in Turbulent Pipe Flow With Relaxation Time of Polymer Additives

2018 ◽  
Author(s):  
Xin Zhang ◽  
Xili Duan ◽  
Yuri Muzychka ◽  
Zongming Wang
Keyword(s):  
Experimental Data ◽  
Relaxation Time ◽  
Drag Reduction ◽  
Pipe Flow ◽  
Polymer Concentration ◽  
Weissenberg Number ◽  
Turbulent Pipe Flow ◽  
Dimensionless Number ◽  
Polymer Additives ◽  
Dilute Solution

This paper presents an experimental study on drag reduction induced by PEO (Polyethylene oxide) in a fully turbulent pipe flow. The objective of this work is to develop a correlation to predict drag reduction using the relaxation time of the polymer additives under dilute solution conditions, i.e., the polymer concentration is less than the overlap concertation. This paper discusses the meaning of relaxation time of polymers, and why the Weissenberg number, a dimensionless number that is related to the relaxation time and shear rate, is independent on the concentration in the dilute solution. Experimental data of drag reduction in a pipe flow are obtained from measurements using a flow loop. A correlation to predict drag reduction with the Weissenberg number and polymer concentration is established and a good agreement is shown between the predicted values and experimental data. The new correlation using the Weissenberg number and polymer concentration is shown to cost less to develop than one using the Reynolds number, in which larger pipes or higher flow rates are required.

Influence of hydrophobe fraction content on the rheological properties of hydrosoluble associative polymers obtained by micellar polymerization

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Enrique J. Jiménez-Regalado ◽  
Elva B. Hernández-Flores
Keyword(s):  
Relaxation Time ◽  
Rheological Properties ◽  
Polymer Concentration ◽  
Water Soluble ◽  
Polymer Chains ◽  
Associative Polymers ◽  
Hydrophobically Modified ◽  
Viscosity Increase ◽  
Increase Rate ◽  
Micellar Polymerization

AbstractThe synthesis, characterization and rheological properties in aqueous solutions of water-soluble associative polymers (AP’s) are reported. Polymer chains consisting of water-soluble polyacrylamides, hydrophobically modified with low amounts of N,N-dihexylacrylamide (1, 2, 3 and 4 mol%) were prepared via free radical micellar polymerization. The properties of these polymers, with respect to the concentration of hydrophobic groups, using steady-flow and oscillatory experiments were compared. An increase of relaxation time (TR) and modulus plateau (G0) was observed in all samples studied. Two different regimes can be clearly distinguished: a first unentangled regime where the viscosity increase rate strongly depends on hydrophobic content and a second entangled regime where the viscosity follows a scaling behavior of the polymer concentration with an exponent close to 4.

scholarly journals Polymer viscosifier systems with potential application for enhanced oil recovery: a review

2021 ◽  
Vol 76 ◽  
pp. 65
Author(s):  
Kelly Lúcia Nazareth Pinho de Aguiar ◽  
Luiz Carlos Magalhães Palermo ◽  
Claudia Regina Elias Mansur
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Polymer Concentration ◽  
High Viscosity ◽  
Water Soluble ◽  
Recovery Factor ◽  
Sweep Efficiency ◽  
Polymeric Fluids ◽  
Excellent Thermal Stability ◽  
Reservoir Conditions

Due to the growing demand for oil and the large number of mature oil fields, Enhanced Oil Recovery (EOR) techniques are increasingly used to increase the oil recovery factor. Among the chemical methods, the use of polymers stands out to increase the viscosity of the injection fluid and harmonize the advance of this fluid in the reservoir to provide greater sweep efficiency. Synthetic polymers based on acrylamide are widely used for EOR, with Partially Hydrolyzed Polyacrylamide (PHPA) being used the most. However, this polymer has low stability under harsh reservoir conditions (High Temperature and Salinity – HTHS). In order to improve the sweep efficiency of polymeric fluids under these conditions, Hydrophobically Modified Associative Polymers (HMAPs) and Thermo-Viscosifying Polymers (TVPs) are being developed. HMAPs contain small amounts of hydrophobic groups in their water-soluble polymeric chains, and above the Critical Association Concentration (CAC), form hydrophobic microdomains that increase the viscosity of the polymer solution. TVPs contain blocks or thermosensitive grafts that self-assemble and form microdomains, substantially increasing the solution’s viscosity. The performance of these systems is strongly influenced by the chemical group inserted in their structures, polymer concentration, salinity and temperature, among other factors. Furthermore, the application of nanoparticles is being investigated to improve the performance of injection polymers applied in EOR. In general, these systems have excellent thermal stability and salinity tolerance along with high viscosity, and therefore increase the oil recovery factor. Thus, these systems can be considered promising agents for enhanced oil recovery applications under harsh conditions, such as high salinity and temperature. Moreover, stands out the use of genetic programming and artificial intelligence to estimate important parameters for reservoir engineering, process improvement, and optimize polymer flooding in enhanced oil recovery.

Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

1987 ◽  
Vol 45 ◽  
pp. 388-389
Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley
Keyword(s):  
Low Dose ◽  
Polymer Concentration ◽  
Processing System ◽  
Limiting Factor ◽  
Dilute Solution ◽  
New Techniques ◽  
Dose Unit ◽  
Lattice Images ◽  
Dose Imaging ◽  
Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

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