Flow characteristics inside shear thinning xanthan gum non-Newtonian droplets moving in rectangular microchannels

2021 ◽  
Vol 62 (10) ◽  
Author(s):  
Mengqi Li ◽  
Zhaomiao Liu ◽  
Yan Pang ◽  
Ju Wang ◽  
Yao Lu ◽  
...  
Keyword(s):  
Xanthan Gum ◽  
Flow Characteristics ◽  
Shear Thinning ◽  
Rectangular Microchannels

scholarly journals Assessment of the Rheological Behavior of Polymer–Oxidant Mixtures and the Influence of the Groundwater Environment on Their Properties

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1698
Author(s):  
Qi Xu ◽  
Jiajun Chen ◽  
Xinran Song
Keyword(s):  
Xanthan Gum ◽  
Control Method ◽  
Shear Thinning ◽  
Mobility Control ◽  
Retention Rates ◽  
Viscosity Reduction ◽  
Leading Role ◽  
Salt Ions ◽  
Groundwater Environment ◽  
Water Ph

Shear-thinning polymers have been introduced to contaminant remediation in the subsurface as a mobility control method applied to mitigate the inefficient delivery of remedial agents caused by geological heterogeneity. Laboratory experiments have been conducted to assess the compatibility of polymers (xanthan and hydrolyzed polyacrylamide (HPAM)) and oxidants (KMnO4 and Na2S2O8) through quantitative evaluation of the viscosity maintenance, shear-thinning performance, and oxidant consumption. The mechanism that causes viscosity loss and the influence of the groundwater environment on the mixture viscosity were also explored. The xanthan–KMnO4 mixture exhibited the best performance in both viscosity retention and shear-thinning behavior with retention rates higher than 75% and 73.5%, respectively. Furthermore, the results indicated that xanthan gum has a high resistance to MnO4− and that K+ plays a leading role in its viscosity reduction, while HPAM is much more sensitive to MnO4−. The viscosity responses of the two polymers to Na2S2O8 and NaCl were almost consistent with that of KMnO4; salt ions displayed an instantaneous effect on the solution’s viscosity, while the oxide ions could cause the solution’s viscosity to decrease continuously with time. Since xanthan exhibited acceptable oxidant consumption as well, xanthan–KMnO4 is considered to be the optimal combination. In addition, the results implied that the effects of salt ions and the water pH on the mixture solution could be acceptable. In the 2D tank test, it was found that when xanthan gum was introduced, the sweeping efficiency of the oxidant in the low-permeability zone was increased from 28.2% to 100%. These findings demonstrated the feasibility of using a xanthan–KMnO4 mixture for actual site remediation.

scholarly journals Evaluation of an alkali-polymer flooding technique for enhanced oil recovery in Trinidad and Tobago

2020 ◽  
Vol 10 (8) ◽  
pp. 3947-3959
Author(s):  
Kyle Medica ◽  
Rean Maharaj ◽  
David Alexander ◽  
Mohammad Soroush
Keyword(s):  
Trinidad And Tobago ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Energy Demand ◽  
Xanthan Gum ◽  
Net Present Value ◽  
Flow Characteristics ◽  
Absorption Capacity ◽  
Polymer Flooding ◽  
Screening Criteria

Abstract Trinidad and Tobago (TT) is seeking to develop more economical methods of enhanced oil recovery to arrest the decline in crude oil production and to meet the current and future energy demand. The utilization of alkaline-polymer flooding to enhance oil recovery in TT requires key studies to be conducted to obtain critical information of the flooding system (soil type, additive type, pH, adsorption characteristics and rheological (flow) characteristics). Understanding the role of, interplay and optimizing of these variables will provide key input data for the required simulations to produce near realistic projections of the required EOR efficiencies. The parameters of various wells in TT were compared to the screening criteria for alkali-polymer flooding, and the EOR 4 well was found to be suitable and thus selected for evaluation. Laboratory adsorption studies showed that the 1000 ppm xanthan gum flooding solution containing 0.25% NaOH exhibited the lowest absorption capacity for the gravel packed sand and exhibited the lowest viscosity at all the tested shear rates. The lowest adsorption was 2.27 × 10−7 lbmole/ft3 which occurred with the 1000 ppm xanthan gum polymer containing 0.25% NaOH, and the evidence showed that the polymer was adsorbed on the other side of the faults, indicating that it has moved further and closer to the producing well. Implementation of an alkali polymer flooding resulted in an incremental increase in the recovery factors (~ 3%) compared to polymer flooding; however, a change in the oil recovery as a function of the alkaline concentration was not observed. The simulated economic analysis clearly shows that all the analysed EOR scenarios resulted in economically feasible outcomes of net present value (NPV), Internal Rate of Return (IRR) and payback period for oil price variations between $35 and $60 USD per barrel of oil. A comparison of the individual strategies shows that the alkali-polymer flood system utilizing 0.25% sodium hydroxide with 1000 ppm xanthan gum is the best option in terms of cumulative production, recovery factor, NPV, IRR and time to payback.

Taylor vortices in Newtonian and shear-thinning liquids

1995 ◽  
Vol 449 (1935) ◽  
pp. 155-176 ◽  
Keyword(s):  
Aqueous Solution ◽  
Axial Velocity ◽  
Xanthan Gum ◽  
Cell Structure ◽  
Outer Wall ◽  
Shear Thinning ◽  
Taylor Number ◽  
Axial Component ◽  
Vortex Cell ◽  
Newtonian Case

The flow structure in a concentric annular geometry with a radius ratio of 0.506 has been investigated for inner cylinder (centrebody) rotation. Detailed velocity measurements made with a laser Doppler anemometer for an aqueous solution of glucose (Newtonian), at a Taylor number well above the critical value, reveal that the tangential velocity component has a periodic structure of the same wavelength as that for the axial component, but with the extrema corresponding to zero axial velocity. Higher values of the maximum axial velocity and velocity gradient are observed closer to the centrebody than at the outer wall, whilst the radial location of zero axial velocity in the vortex interior (i. e. the eye of the vortex) moves towards the outer wall with increasing Taylor number. Similar measurements for an aqueous solution of Xanthan gum, which is strongly shear thinning and slightly elastic, revealed that the asymmetry in the maximum axial velocities was more marked than for the Newtonian case with a significant radial shift in the location of the vortex eye towards the centrebody. It was also found that the vortices exhibit a slow axial drift in the direction opposite to the centrebody rotation vector, whereas there was zero drift in the Newtonian case. The vortex cell structure for the second non-Newtonian fluid, a Laponite/CMC aqueous blend, which is shear thinning and also thixotropic, was very similar to that for the Xanthan gum suggesting that the shear-thinning aspect of the fluid rheology for both non-Newtonian fluids was far more significant than either thixotropy or viscoelasticity. An axial drift was again apparent, but in the opposite direction to that for the Xanthan gum, indicating that this effect is associated with the differences in the rheological characteristics of the two fluids.

scholarly journals Flow Characteristics of the Entrance Region with Roughness Effect within Rectangular Microchannels

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 30
Author(s):  
Haiwang Li ◽  
Yujia Li ◽  
Binghuan Huang ◽  
Tiantong Xu
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Stokes Equations ◽  
Critical Role ◽  
Flow Characteristics ◽  
Entrance Region ◽  
Working Fluid ◽  
Asymmetric Distribution ◽  
Rectangular Microchannels ◽  
Aspect Ratios

We conducted systematic numerical investigations of the flow characteristics within the entrance region of rectangular microchannels. The effects of the geometrical aspect ratio and roughness on entrance lengths were analyzed. The incompressible laminar Navier–Stokes equations were solved using finite volume method (FVM). In the simulation, hydraulic diameters ( D h ) ranging from 50 to 200 µm were studied, and aspect ratios of 1, 1.25, 1.5, 1.75, and 2 were considered as well. The working fluid was set as water, and the Reynolds number ranged from 0.5 to 100. The results showed a good agreement with the conducted experiment. Correlations are proposed to predict the entrance lengths of microchannels with respect to different aspect ratios. Compared with other correlations, these new correlations are more reliable because a more practical inlet condition was considered in our investigations. Instead of considering the influence of the width and height of the microchannels, in our investigation we proved that the critical role is played by the aspect ratio, representing the combination of the aforementioned parameters. Furthermore, the existence of rough elements obviously shortens the entrance region, and this effect became more pronounced with increasing relative roughness and Reynolds number. A similar effect could be seen by shortening the roughness spacing. An asymmetric distribution of rough elements decreased the entrance length compared with a symmetric distribution, which can be extrapolated to other irregularly distributed forms.

scholarly journals Effects of Ionic Strength on Lateral Particle Migration in Shear-Thinning Xanthan Gum Solutions

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 535 ◽  
Author(s):  
Mira Cho ◽  
Sun Ok Hong ◽  
Seung Hak Lee ◽  
Kyu Hyun ◽  
Ju Min Kim
Keyword(s):  
Ionic Strength ◽  
Rheological Properties ◽  
Viscoelastic Fluid ◽  
Xanthan Gum ◽  
Viscoelastic Fluids ◽  
Shear Thinning ◽  
Particle Migration ◽  
Cell Counting ◽  
Contour Length ◽  
Wide Range

Viscoelastic fluids, including particulate systems, are found in various biological and industrial systems including blood flow, food, cosmetics, and electronic materials. Particles suspended in viscoelastic fluids such as polymer solutions migrate laterally, forming spatially segregated streams in pressure-driven flow. Viscoelastic particle migration was recently applied to microfluidic technologies including particle counting and sorting and the micromechanical measurement of living cells. Understanding the effects on equilibrium particle positions of rheological properties of suspending viscoelastic fluid is essential for designing microfluidic applications. It has been considered that the shear-thinning behavior of viscoelastic fluid is a critical factor in determining the equilibrium particle positions. This work presents the lateral particle migration in two different xanthan gum-based viscoelastic fluids with similar shear-thinning viscosities and the linear viscoelastic properties. The flexibility and contour length of the xanthan gum molecules were tuned by varying the ionic strength of the solvent. Particles suspended in flexible and short xanthan gum solution, dissolved at high ionic strength, migrated toward the corners in a square channel, whereas particles in the rigid and long xanthan gum solutions in deionized water migrated toward the centerline. This work suggests that the structural properties of polymer molecules play significant roles in determining the equilibrium positions in shear-thinning fluids, despite similar bulk rheological properties. The current results are expected to be used in a wide range of applications such as cell counting and sorting.

Effect of Maltodextrin on Physical Properties of Granulated Xanthan Gum Prepared by Fluidized-Bed Granulator

2017 ◽  
Vol 13 (8) ◽  
Author(s):  
Yong-Hwan Kim ◽  
Sung-Gun Kim ◽  
Byoungseung Yoo
Keyword(s):  
Physical Properties ◽  
Fluidized Bed ◽  
Xanthan Gum ◽  
Loss Modulus ◽  
Flow Characteristics ◽  
Flow Properties ◽  
Main Ingredient ◽  
Granulation Process ◽  
Hausner Ratio ◽  
Tan Δ

AbstractFluidized-bed granulation has received considerable attention within the food process industry because granulated products often have improved flowability and appearance, and sometimes have specifically enhanced physical properties. In this study, the rheological properties of granulated xanthan gum (XG), commonly used as a main ingredient in food thickeners for dysphagia diets, were investigated at different concentrations (0, 5, 10, and 15 % w/w) of maltodextrin (MD) as a binder at different concentrations. Flowability and cohesiveness of granulated XG powder was also evaluated in terms of as Carr index (CI) and Hausner ratio (HR) were also investigated. The consistency index, apparent viscosity, storage modulus (G’) and loss modulus (G”) of granulated XG were significantly higher than those of non-granulated XG and granulated XG without binder (0 % MD). The tan δ values of granulated samples were lower compared with that of a non-granulated sample, indicating that their elastic properties were more pronounced because of the granulation. These rheological results also showed that there were no noticeable changes in flow properties between 0 % and 5 % MD concentrations, whereas the G’ and G” values at 10 % MD were much higher than those at other concentrations. The granulation process by MD binder also enhanced considerably flow characteristics of XG powder.

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