Study on the Rheological Properties of PTFE/PVA Blended Solution

2011 ◽  
Vol 233-235 ◽  
pp. 2934-2937
Author(s):  
Yao Wu Wang ◽  
Run Jun Sun ◽  
Zhao Huan Zhang ◽  
Li Ping Chen ◽  
Mu Yao
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Shear Thinning Fluid

PTFE suspension latex and PVA solution are blended at different ratio, and the rotary rheometer is used to test the rheological properties of these solutions. The result shows that both PTFE suspension latex and PTFE/PVA blended solution are all shear thinning fluid; with increasing shear rate, apparent viscosity decreases; with increase of PVA content in blended solution, apparent viscosity and Non-Newtonian index increase, and spinnability of blended solution can be improved; with increase of temperature, the apparent viscosity decreases.

Acoustic Heating Produced in the Thermoviscous Flow of a Shear-Thinning Fluid

2011 ◽  
Vol 36 (3) ◽  
pp. 629-642
Author(s):  
Anna Perelomova
Keyword(s):  
Shear Rate ◽  
Differential Form ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Nonlinear Flow ◽  
Dynamic Equations ◽  
Weakly Nonlinear ◽  
Piecewise Constant ◽  
Shear Thinning Fluid ◽  
Constant Shear Rate

AbstractThis study is devoted to the instantaneous acoustic heating of a shear-thinning fluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. That feature distinguishes it from a viscous Newtonian fluid. The special linear combination of conservation equations in the differential form makes it possible to derive dynamic equations governing both the sound and non-wave entropy mode induced in the field of sound. These equations are valid in a weakly nonlinear flow of a shear-thinning fluid over an unbounded volume. They both are instantaneous, and do not require a periodic sound. An example of a sound waveform with a piecewise constant shear rate is considered as a source of acoustic heating.

Development of Viscosified Acid-Surfactant Solutions for Oilfield Applications: Rheological Properties

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Lionel Talley Fogang ◽  
Muhammad Shahzad Kamal ◽  
Mohamed Mahmoud
Keyword(s):  
Shear Rate ◽  
Acid Solution ◽  
Rheological Properties ◽  
Calcium Chloride ◽  
Elastic Properties ◽  
Salt Concentration ◽  
Shear Thinning ◽  
Rate Range ◽  
Shear Rates ◽  
Surfactant Solutions

Abstract Viscosified acids are desired in several oilfield applications such as in acid diversion and acid fracturing operations. The study aimed to delineate the rheological properties of a novel amine type surfactant and viscosified acid-surfactant solutions. The steady shear and dynamic rheological properties were evaluated by varying the surfactant, acid, and salt concentration. Such a study is required to gauge the suitability of the viscosifying agent in acid stimulation jobs. The surfactant solutions without acid showed shear-thinning behavior, whereas those with acid showed a Newtonian plateau over a wide shear rate range before undergoing shear thinning. This means that over a wide shear rate range, the acid-surfactant solutions become independent of applied shear. At low shear rates, the viscosity of the surfactant was higher compared with the surfactant-acid solution. However, at high shear rates, the viscosity of the surfactant was lower compared with the viscosity of the surfactant-acid solution. There was an optimal salt concentration that improved the viscosity and elasticity of the acid-surfactant solutions. Thus, the rheology of the surfactant solution can be improved by adding both acid and salt. The elastic properties of acid-surfactant solutions were also better compared with the elastic properties of pure surfactant. The addition of acid improved the elastic properties of the surfactant solutions. Constant viscosity over a range of shear rate is a suitable application for acid fracturing operations in which the acid leak-off will be minimal due to the high viscosity. Also, brines in most of the carbonate formation consist of high loading of calcium chloride which was found to have a positive effect on the viscosity. Increasing the calcium chloride leads to an increase in viscosity, and then subsequently decreases the viscosity. This shows that the acid and salt concentration plays a role in modifying the rheological properties of the surfactant solutions.

scholarly journals Shear thinning and thickening of cemented paste backfill

2019 ◽  
Vol 29 (1) ◽  
pp. 80-93 ◽  
Author(s):  
Liuhua Yang ◽  
Hongjiang Wang ◽  
Aixiang Wu ◽  
Hong Li ◽  
Arlin Bruno Tchamba ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Shear Thinning ◽  
High Shear ◽  
Cemented Paste Backfill ◽  
Concentrated Suspension ◽  
History Effects ◽  
Paste Backfill ◽  
Shear History

Abstract Cemented paste backfill (CPB) is considered to be a concentrated suspension in which tailings are bonded together by the hydraulic binder and water, and it has a high solid volume concentration (≥50 vol.%). Although the shear thinning and thickening of CPB has been extensively reported in literature, the shear history effects have been ignored in previous studies. In this paper, by using rheometer and Focused Beam Reflectance Measurement, the relationship between the rheological properties and microstructure of the paste under different shear histories was studied. The results have shown that at a low shear rate, CPB revealed shear thinning, low yield stress and low index parameters; while exhibited shear thickening, high yield stress and high consistency index when at high shear rates of shear history. This agreed with the general trends shown in the FBRM analysis. It was proposed that the action of shear is beneficial to particle dispersion, whereas a high shear rate history tends to promote the aggregation of particles. It was revealed that both shear thinning and thickening of paste are related to the situation of particles (flocculation, dispersion and aggregation), and shear history effects play an important role in rheological properties of CPB.

Rheological Properties of Aircraft Grease Containing Nano-Additives

2009 ◽  
Vol 419-420 ◽  
pp. 53-56
Author(s):  
Bao Yu Song ◽  
Qing Xiang Yang ◽  
Feng Zhang ◽  
Dai Zhong Su
Keyword(s):  
Rheological Properties ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Nano Particles ◽  
Rheological Parameters ◽  
Nanoparticle Concentration ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
The One ◽  
The Given

The apparent viscosity of aircraft grease with different nano-particles content, temperature and shear rates were studied using a rotational viscometer. The rheological properties of two types of aircraft grease, the basic grease and the one with nano-particles additives, were investigated using a rheometer. The results indicated that the apparent viscosity increases with the increase of nanoparticle concentration with the given ratio of nano-particles added. It was also found that the grease with and without the nano-particles both have yield stresses and clear shear-thinning properties. The shear-thinning phenomenon of the grease containing nano-particles is more evident than that of the basic grease. The experimental results also reveal that the rheological characteristics of both types of grease fall in Herschel-Bulkley class, and the nano-particles have a significant influence on the rheological parameters. At the end, the rheology mechanism was discussed based on the entanglement and orientation theories.

Rheology of pulp suspensions of bleached sugarcane bagasse: Effect of consistency and temperature

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 601-606 ◽  
Author(s):  
JORGE H. SÁNCHEZ ◽  
GERMÁN C. QUINTANA ◽  
MERY E. FAJARDO
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Sugarcane Bagasse ◽  
Power Law ◽  
Apparent Viscosity ◽  
Power Law Model ◽  
Pulp Suspensions ◽  
Concentric Cylinders ◽  
Rate Controlled

Rheological properties, such as yield stress and apparent viscosity, of pulp suspensions of bleached sugarcane bagasse were studied in a stress-shear rate controlled rheometer using concentric cylinders geometry. Results were statistically analyzed and presented as a function of the suspension consistency (0.5% ≤ Cm ≤ 4.0%) and temperature (20°C, 40°C, and 60°C). The yield stress was influenced by the consistency and temperature. The apparent viscosity was influenced only by the consistency. A power law model was fitted to the experimental results of yield stress. In flow tests, all the suspensions showed shear-thinning behavior, which was in agreement with the Carreau-Yasuda model.

Rheological Properties of Polysulfonamide Spinning Solutions with Higher Ratios of p-Phenylene Segments

2013 ◽  
Vol 683 ◽  
pp. 289-292
Author(s):  
Hu Min Li ◽  
Xiao Jie Peng ◽  
Jiong Xin Zhao
Keyword(s):  
Mechanical Property ◽  
High Temperature ◽  
Shear Rate ◽  
Rheological Properties ◽  
Synthetic Fiber ◽  
Static State ◽  
Temperature Resistance ◽  
The Poor ◽  
Different Temperatures ◽  
Shear Thinning Fluid

Polysulfonamide (PSA) fiber is a kind of synthetic fiber with excellent high temperature resistance properties. However, the poor mechanical property has limited its application. In our previous research, we have concluded that the presence of more rigid segments of p-phenylene in the PSA copolymer backbone enhanced the strength and modulus of the fiber. In this paper, the rheological properties of PSA spinning solutions with higher contents of 4,4'-diaminodiphenylsulfone (4,4'-DDS) were investigated. Static state rheological properties of PSA spinning solutions were investigated by measuring the apparent viscosity versus shear rate at different temperatures. The results showed that three types of PSA spinning solutions were typical shear thinning fluid. And the spinning solutions of PSA with different ratios of 4,4'-DDS and 3,3'-diaminodiphenylsulfone (3,3'-DDS) showed the similar rheological properties, which meant that the spinning equipment and technologic parameter did not need to be updated to produce new PSA fibers.

Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion

2013 ◽  
Vol 747 ◽  
pp. 627-630
Author(s):  
Watcharapong Chookaew ◽  
Yanichsa Sukniyom ◽  
Somjate Patcharaphun ◽  
Narongrit Sombatsompop
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Wall Slip ◽  
Skin Layer ◽  
Rubber Compound ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
Capillary Extrusion

The influences of shear rate and vulcanizing system on the rheological properties and melt fracture of natural rubber compounds were investigated by using a rate-controlled capillary rheometer. The rheological properties of rubber compounds were characterized with respect to the apparent viscosity and extrudate swell. The measured results indicated that the apparent viscosity tended to decrease with increasing shear rate. This was due to the pseudoplastic behavior of molten rubber compound. It was evident that rubber compound using EV system showed the lowest apparent viscosity as compared to those obtained by CV and NS systems, respectively. This was due to the occurrences of premature crosslink at the skin layer and the wall slip of rubber compound during the flow in capillary die. Furthermore, the onset of smooth surface was also observed which depending on the types of crosslink at the skin layer.

Rheological Characteristics of Surfactant-Based Fluids: A Comprehensive Study

2018 ◽  
Author(s):  
Ahmed H. Kamel
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Surfactant Concentration ◽  
Flow Direction ◽  
Shear Thinning ◽  
Molecular Structures ◽  
Wide Range ◽  
Unique Nature ◽  
Viscoelastic Surfactant

Surfactant-based fluids, SB fluids exhibit complex rheological behavior due to substantial structural change caused by the molecules self-assembled colloidal aggregation. Various factors affect their rheological properties. Among these factors, surfactant concentration, shear rate, temperature, and salinity are investigated. One of the most popular surfactants, Aromox® APA-T viscoelastic surfactant (VES) is examined. The study focuses on four different concentrations (1.5%, 2%, 3%, and 4%) over a shear rate ranging from 0.0526 sec−1 to 1944 sec−1 using Bohlin rheometer. For salinity effects, two brine solutions are used; 2 and 4% KCl while for temperature effects, a wide range from ambient temperature of 72°F up to 200°F is covered. The results show that SB fluids exhibit a complex rheological behavior due to its unique nature and the various structures form in the solution. In general, SB fluids at all concentrations exhibit a non-Newtonian pseudo-plastic shear thinning behavior. As the surfactant concentration and/or shear increases, a stronger shear thinning behavior can be seen. Increasing solution salinity promotes formation of rod-like micelles and increases its flexibility. Salinity affects micelles’ growth and their rheological behavior is very sensitive to the nature and structure of the added salt. Different molecular structures are formed; spherical micelles occur first and then increased shear rate and/or salinity promotes the formation of rod-like micelles. Later, rod-like micelles are aligned in the flow direction and form a large super ordered structure of micellar bundles or aggregates called shear induced structure (SIS). Different structures implies different rheological properties. Likewise, rheology improves with increasing temperature up to 100°F. Further increase in temperature reverses the effects and viscosity decreases. However, the effects of temperature and salinity diminish at higher shear rates. Furthermore, a rheology master curve is developed to further understand the rheological behavior of SB fluids and correlate rheological properties to its microscopic structure.

Laponite Nanoparticle as a High Performance Rheological Modifier in Water-Based Drilling Fluids

2018 ◽  
Vol 917 ◽  
pp. 134-139
Author(s):  
Fan Liu ◽  
Guang Cheng Jiang ◽  
Kai Wang ◽  
Jin Xi Wang
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Point ◽  
High Performance ◽  
Shear Thinning ◽  
Drilling Fluids ◽  
Star Network ◽  
Water Based ◽  
Rate Test ◽  
Rheological Modifier

In this paper, we demonstrated an artificial nanoparticles, Laponite, as a high performance rheological modifier in water-based drilling fluids. We made a comparison between Laponite nanoparticle and bentonite as rheological modifier in polyanionic cellulose (PAC) solution and weitghted water-based drilling fluids. In viscosity-shear rate test, both Laponite and bentonite could translate 0.5 wt.% PAC solution from Newton fluids to yield-pseudoplastic fluid. However, 1 wt.% Laponite was better in improving the shear-thinning behavior compared with 4 wt.% bentonite. In the stress-shear rate test, the results were fit with Bingham model with a high R2, and 1 wt.% Laponite/0.5 wt.% PAC suspension had a yield point of 5.19 Pa, which was higher than that of 4 wt.% bentonite/0.5 wt.% PAC suspension (3.13 Pa). Similarly, 1 wt.% Laponite/0.5 wt.% PAC suspension maintained a G’ of 12 Pa in the oscillation frequency sweep test, whereas G’ of 4%bentonite/0.5%PAC suspension was nearly 5 Pa. Particularly, 0.5 wt.% PAC /Laponite suspensions could maintain higher gel structure, yield point and better shear-thinning behaviors after 120°C hot rolling. The TEM image revealed that nanoscaled Laponite could form a “star network” with PAC in water, which explained the good rheological properties of PAC/LAP mixed suspensions. Besides, in the weighted drilling fluids, 1 wt.% Laponite could maintained a much higher gel strength compared with 4 wt.% bentonite.As the unique rheological properties, Laponite nanoparticles can greatly enhance abilities of water-based drilling fluids in circulating cuttings and making the borehole clean.

A Rheological Model of Semisolid Magnesium Alloy Slurries

2005 ◽  
Vol 488-489 ◽  
pp. 333-336 ◽  
Author(s):  
L. Li ◽  
X.W. Zhou ◽  
J.Y. Chen
Keyword(s):  
Magnesium Alloy ◽  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Rheological Model ◽  
The State ◽  
Simple Shearing ◽  
Flow Conditions ◽  
Rheological Behaviors ◽  
Microstructure Model

In this paper a rheological model is presented which describes the rheological behaviors of liquid-like semisolid magnesium alloy under a simple shearing flow. On the basis of Chen and Fan’s mono-dispersion microstructure model of semisolid metal slurry, the particle size distribution is considered in this model. It is believed that it is the state of agglomeration which determines the rheological behaviors of the slurry, whereas the external flow conditions such as shear rate and shearing time, affect the rheological properties by changing the state of agglomeration. The expressions of collision rate between two agglomerates, effective solid fraction and the formula of apparent viscosity of Chen and Fan’s model are corrected according to the experimental results and statistical mechanics. Finally calculated apparent viscosity and the average number of the particles of AZ91D by the developed model as functions of shear rate are presented. These results show that there is a one to one coupling between the rheological properties of the magnesium alloy slurries and the state of the agglomeration.

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