Xanthan Gum Solutions Research Articles

A model to calculate the pressure loss of Newtonian and non-Newtonian fluids flow in coiled tubing operations

The coiled tubing is a system consisting of a long, continuous and flexible steel pipe used in many processes, especially in the oil industry. As the fluid flow in curved pipes generates significant energy dissipation compared to a straight pipe, it is essential to predict the pressure drop to obtain the pumping pressure to be used in the operation and optimize process control. In this work, the pressure drop in the flow of Newtonian and non-Newtonian fluids was evaluated in a pilot unit and a mathematical model was developed to simulate the pressure drop along the coiled tube. Water and an aqueous solution of xanthan gum, with rheological power-law parameters similar to those observed in cement slurries, were used in experimental tests. The experimental unit is 375 m long divided into 8 layers with pressure measurements in each layer where fluids were pumped at different volumetric flow rates and curvature ratios. A mathematical model was proposed to calculate the pressure drop assuming the existence of a sequential pumping of different fluids along the coiled tubing, with different curvature ratios and internal tube diameters. The mathematical modeling could predict the pilot experiments for Newtonian fluids and, based on the results obtained in the laboratory, the parameters of a friction factor correlation for non-Newtonian fluids present in the literature were re-estimated. A case study of a real well abandonment operation with a coiled tubing system was used to validate the proposed modeling. The developed software was used to simulate the real conditions, where a good approximation to the field data was observed, with a percentage error between the experimental and calculated values below 7%.

Effect of oil on the performance of biopolymers as drag reducers in fresh water flow

This study looks at the effectiveness of natural polymers (biopolymers) as drag reducers in flows of oil-water mixtures. The technique of using drag reducers to minimize the frictional drag in pipeline transportation of fluids is getting more challenging and there is need to be more environmentally friendly by using natural polymers. In this report, two natural polymers: xanthan gum (XG) and guar gum (GG), were used as drag reducers in a 12-mm ID straight conduit with water. The concentration of the gums was varied from 50 to 250 pm while 25, 0.50 and 0.75 fractions of oil were mixed with freshwater. The molecular weight of the gums was also determined to gain insight into their influence on the rheology of the fluids. The result showed that the gums (natural polymers) performed better as drag reducer in freshwater than in mixture with oil. Specifically, the drag reduction (DR) of 200 pm GG and XG solutions at Reynolds number of 59000 in freshwater was 39% and 44% respectively, while with the addition of 50% oil fraction, it was reduced to 19% and 32% respectively. DR reduced with oil fraction. It was concluded that XG performs better in the presence of oil than GG.

Hysteresis effect of propeller jet flows in viscoelastic fluids: Transformation process and turbulence intensity

This work aimed to investigate the flow pattern transformation process resolved in time and to propose a physical explanation for the hysteresis effect of a propeller jet in a viscoelastic fluid. The propeller jet flow in xanthan gum solution was measured using PIV (Particle Image Velocimetry) and UVP (Ultrasound Velocity Profiler). Based on the distribution of turbulence intensity, the semi-radial and the axial flow patterns generated at the same rotational speed were classified as laminar and turbulent flow, respectively. Therefore, the Reynolds number was considered inappropriate to characterize the flow fields in the hysteresis range, since both laminar and turbulent flow may occur at the same Reynolds number. The distribution of normal stresses derived from the flow induced structure was considered as the determining factor for the flow field formation.

Semi-continuous production of xanthan in biofilm reactor using Xanthomonas campestris

Semi-continuous production of xanthan gum using self-immobilized Xanthomonas campestris cells in biofilm reactors was studied. Fermentation was carried out using two different designs of biofilm reactor equipped with a) stainless-steel support (SSS) and b) polyethylene support (PES). Fermentation was performed in three cycles with refreshing the media at the beginning of each: cycle 1, 0−27 h; cycle 2, 27−54 h; and cycle 3, 54–78.5 h. Results showed that the glucose consumption and the pH reduction in the PES biofilm reactor was faster compared to the SSS biofilm reactor. Scanning electron microscopy showed that the SSS was capable to immobilize more cells during the growth of X. campestris. The maximum concentration of xanthan gum in the SSS biofilm reactor obtained after 27 h (3.47 ± 0.71 g/L), while the maximum concentration of xanthan in the PES biofilm reactor obtained after 78.5 h (3.21 ± 0.68 g/L). Thermal stability analysis of xanthan using differential scanning calorimetry showed the presence of two fractures attributed to dehydration and degradation of polymer. The thermogram represented both endothermal and exothermal behaviour of xanthan polymer. Furthermore, the functional groups and molecular structure of the xanthan produced in this study was evaluated using Fourier transform infrared spectrometry and also proton nuclear magnetic resonance. in addition, the surface tension of (0.2 %, w/v) xanthan gum solution was in a range of 52.16–56.5 mN/m. Rheological analysis of xanthan showed that the G′ values were higher than the G″ in all frequencies demonstrating a relatively high elasticity of the produced xanthan gum.

Effect of Silica Nanoparticles in Xanthan Gum Solutions: Rheological Behavior and Preparation Methods of Nanofluids

Effect of Silica Nanoparticles in Xanthan Gum Solutions: Rheological Behavior and Preparation Methods of Nanofluids

Constriction length dependent instabilities in the microfluidic entry flow of polymer solutions.

Transport phenomena of fluids and particles through contraction and/or expansion geometries have relevance in many applications. Polymer solutions are often the transporter in these processes, giving rise to flow complexities. The separation distance between a contraction and a following expansion in microfluidic entry flow can affect the interplay between the shear and extension force dominated flow regimes, but the process is still little understood. We investigate the rheological responses of such constriction length dependent instabilities with three different polymer solutions and water in planar contraction-expansion microchannels differing only in the constriction length. The viscoelastic polyethylene oxide (PEO) solution is found to exhibit strong constriction length-dependent instabilities in both the contraction and expansion flows. Such a dependence is, however, completely absent from the flow of shear-thinning xanthan gum (XG) solution and Newtonian water. Interestingly, it is only present in the expansion flow of the both shear thinning and viscoelastic polyacrylamide (PAA) solution.

Experimental determination and modeling of flow curves of xanthan gum solutions over a large range of shear rates

AbstractThe viscosities of solutions formulated with xanthan gum and xanthan gum with whey protein isolates are experimentally characterized and modeled over a wide range of shear rates [10−3to 105s−1]. As shown by numerous studies [1, 2], the generation of vortices in the cone-plate geometry is making viscosity measurements beyond a certain shear rate unreliable. In the present work, an innovative technique, based on microfluidics and developed by the company Formulaction, has been employed to extend to high shear rates, the viscosity flow curve obtained with a rotational rheometer. The main highlights of this study are firstly, to propose a scaling law for the inertial transition in the cone-plate geometry for different diameters and angles through the determination of the maximum shear rate at which one can expect a true viscosity value. Secondly, the high shear rate measurements allow the determination of the second Newtonian plateau for these solutions thanks to the Williams-Carreau model. An attempt for the second plateau modeling is proposed following the concept of an intrinsic viscosity in the high shear equilibrium. In the same way, other fitted parameters from the Williams-Carreau law are modeled as a function of the polymer concentration. This procedure allows to provide a predictive model for the rheological behavior of xanthan gum-based solutions used in high shear processes like high pressure homogenization, emulsification, foaming, microfluidics, etc in food, pharmaceutical or cosmetics applications.

Spray technology applications of xanthan gum-based edible coatings for fresh-cut lotus root (Nelumbo nucifera)

In this study, the effect of spraying method as an application technique for xanthan gum-based edible coatings was investigated, based on its barrier and microbial properties on fresh-cut lotus root. Xanthan gum solutions (0.1%, 0.3%, and 0.5%) were prepared and incorporated with 2% (w/w) citric acid as an anti-browning agent and 1% (w/w) glycerol as plasticizer. The coatings were then sprayed using a pilot spray system to 5 mm-thick slices of fresh-cut lotus root for 20 s, packed in polyethylene bags, stored for 16 d at 5 °C and analyzed for color, pH, morphology and microbial counts. It was found that spray-coated fresh-cut lotus root samples had significant reduction in the total color changes as compared to non-coated samples. The experimental results suggested that the spray coating treatments were effective in decreasing the enzymatic browning of fresh-cut lotus root during storage which could potentially increase its shelf-life in the market. In addition, we have also found that the xanthan gum-based spray coated treatments were also effective against inhibiting the growth of Bacillus subtilis during 24 h of incubation which were indicated by the lower microbial counts recorded as compared to non-coated fresh-cut lotus root samples. In this part of the work, the author highlighted the spray coating technique of xanthan gum-based edible coatings as a promising strategy in improving the storage stability of fresh-cut lotus root during post-harvest storage. Overall, the application of edible coatings is a promising strategy in extending the shelf life of fresh-cut lotus root. In the future, the author aims to widen the scope of the application of these coatings to other agricultural products which are prone to degradation during storage in the market.

Mixing of non-Newtonian inelastic fluid in a turbulent patch of T-junction

In this paper, we present result from a direct numerical simulation (DNS) of turbulent flow in a converging T-junction for both Newtonian (water) and non-Newtonian inelastic fluid (dilute Xanthan Gum solution). Based on experimental data, the Bird-Carreau law is used to capture the inelastic shear thinning property of the solution. For the Xanthan solution, the viscosity at rest is about 100 times greater than the viscosity at high shear-rate. A passive scalar is introduced in the transverse branch to investigate the mixing in such configuration. The nominal Reynolds number at the exit varies from 4800 to 8000 for the Newtonian cases and for the same inflow rates, the non-Newtonian flow will be necessarily at lower nominal Reynolds number. Two regimes are explored as a function of the inlet velocity ratio r=Ub/Um : the ”deflecting” regime noted DR (r=1) and the ”impinging” regime noted IR (r=4). For the non-Newtonian cases, two viscous cores are observed before the junction. After the junction a laminar state is obtained for the lower flow rate conditions. Surprisingly, in spite of a large viscosity at rest, a self-sustained non-Newtonian turbulence is achieved except for one case. We describe existing vortex mechanisms which pilot the scalar mixing. In addition, we show that in the non-Newtonian cases, the existing peak of turbulence is only shifted in the DR case. The shift is probably due to the nature of the fluid and not to the dynamical regime. After an intense turbulent zone, we show that a re-laminarization zone appears in the non-Newtonian case which reduces the fluctuation as well as mixing. As a result, IR has a better mixing quality than DR.

PTV measurements of oscillating grid turbulence in water and polymer solutions

Particle Tracking Velocimetry (PTV) is applied to measure the flow in an oscillating grid stirred tank filled with either water or shear thinning dilute polymer solutions (DPS) of Xanthan Gum (XG). There are many interests of studying turbulence in such complex non-Newtonian fluids (e.g. in the pharmaceutical, cosmetic, or food industry), and grid stirred tanks are commonly used for fundamental studies of turbulence in Newtonian fluids. Yet the case of oscillating grid flows in shear thinning solutions has been addressed recently by Lacassagne et al. (Exp Fluids 61(1):15, Phys Fluids 31(8):083102, 2019a, b), with only a single two dimensional (2D) Particle Image Velocimetry (PIV) characterization of mean flow and turbulence properties in the central vertical plane of the tank. Here, PTV data processed by the Shake The Box algorithm allows for the time resolved, three dimensional (3D) 3 components (3C) measurement of Lagrangian velocities for a large number of tracked particles in a central volume of interest of the tank. The possibility of projecting this Lagrangian information on an Eulerian grid is explored, and projected Eulerian results are compared with 2D PIV data from the previous work. Even if the mean flow is difficult to reproduce at the lowest polymer concentrations, a good agreement is found between measured turbulent decay laws, thus endorsing the use of this 3D-PTV metrology for the study of oscillating grid turbulence in DPS. The many possibilities of further analysis offered by the 3D3C nature of the data, either in the original Lagrangian form or in the projected Eulerian one, are finally discussed.Graphic

Cavern Boundary Determination with Pseudoplastic Fluid Based on the Apparent Viscosity Method

AbstractThe cavern characteristics of xanthan gum solutions stirred by impellers of a perturbed six‐bent‐bladed turbine (6PBT) were investigated numerically using computational fluid dynamics (CFD) with laminar flow model. The apparent viscosity method was proposed to determine the boundary of the cavern. The cavern sizes predicted by apparent viscosity were in good agreement with the calculated results, and this method was not influenced by speed and impeller configuration. However, the predicted results of the cavern by the traditional speed method usually displayed a great deviation, especially at high speed. Therefore, it is feasible to determine the cavern boundary with the apparent viscosity, i.e., 0.25 times the yield viscosity of a pseudoplastic fluid, as the unified standard.

Xanthan gum as an alternative to replace the fat for coating and flavoring the extruded snacks.

Food industries adapt their products and processes to the needs and desires of consumers. Extruded snacks include 10-20% fat sprinkled to fix flavors, seasonings, and salt. Considering the need to flavor snacks and simultaneously reduce the intake of calories, a polysaccharide is proposed in this study as a fat replacer. Impact of aqueous xanthan gum (Xg) solutions (0.25, 0.5, 1.0%) under two pH conditions (3.5 and 7.0) on structural and sensory characteristics of extruded snacks was analyzed. Rheological features of the coating solutions, as flow behaviour and viscoelastic profile (storage and loss moduli), were assessed. Texture analysis, to evaluate the snacks firmness and moisture content, water activity, retraction, and agglomeration index of the coated snacks, were also evaluated. Results for the aqueous Xg coatings were very encouraging showing good coating properties, not damaging the texture of the extrudates or causing agglomeration. Sensory analysis reflected a good overall acceptability of these snacks, as compared to oil-coated snacks. Therefore, xanthan gum should be used by the industry, to replace fat, on extruded snacks flavor coating solutions.

Effect of hypergravity on the modification of xanthan gum

To improve the properties of xanthan gum (XG), 3-chloro-2-hydroxypropyltrimethylammonium chloride and propylene oxide were used as modifiers to etherify XG and to obtain cationic hydroxypropyl xanthan gum (HCXG), and cationic hydroxypropyl xanthan gum (CHCXG), further optimized by super-gravity reaction. The structure of the product was characterized by infrared spectroscopy and nuclear magnetic resonance. The rheological properties of XG, HCXG, and CHCXG solutions and their performance as fracturing fluids were studied. Infrared and nuclear magnetic test results showed that the cationic etherification agent and hydroxypropyl group were successfully connected to XG, and the degree of substitution of CHCXG was higher. The rheological properties of the CHCXG solution and the performance of the fracturing fluid base fluid were superior to those of the XG and HCXG solutions. The viscosity of the solution after the super-gravity modification was further increased, and the apparent viscosity of the 0.4% CHCXG solution was 28.96% higher than that of the HCXG solution. After XG modification, the solution strength, yield stress, viscoelasticity, temperature resistance, and shear resistance were all significantly improved. The rheological properties of the HCXG solution and the performance of the fracturing fluid base fluid are good and can be used for fracturing fluid thickener.

Generation of Newtonian droplets in Newtonian and non-Newtonian carrier flows in micro T-junctions under opposed-flow configuration

In this paper the generation of Newtonian microdroplets in both Newtonian and non-Newtonian carrier fluids through a commercial micro T-junction under an opposed-flow configuration is analyzed experimentally. Pure deionized water and 0.2 wt% aqueous Xanthan gum solution in presence or absence of surfactant (Tween 20) have been considered as carrier fluids and the silicone oil is employed as the dispersed phase. The role of surfactant as a promoter of the generation of a droplet-based flow at the outlet of the T-junction is analyzed. Squeezing, dripping, jetting and parallel flow regimes have been generated by varying the flow rates of the dispersed and continuous phases at the inlets of the junction. A series of flow maps is presented in order to facilitate the design prediction of the droplet flow patterns generated at the outlet of the junction by varying the Capillary number and/or the inlet volumetric flow rates of Newtonian and non-Newtonian fluids. In the current paper, detailed information about the typical values of the droplet breakup distance from the center of the T- junction is demonstrated and the typical droplet length and polydispersity values are studied as a function of the inlet flow rate ratio and Capillary number.

Shear wave velocity anisotropy of salt- and polymer-amended kaolinite

Shear wave velocity (Vs) anisotropy of kaolinite mixed with sodium chloride (NaCl) and organic polymer (polyethylene oxide, xanthan gum, and chitosan) solutions was investigated using a custom-made floating wall consolidometer-type bender element testing system. The addition of salt and polymers influenced the microfabric anisoopy of platy kaolinite particles, thus resulted in the increment or decrement in the Vs anisotropy. The Vs of kaolinite in all three orthogonal directions increased as the NaCl concentration increased; however, the Vs anisotropy decreased. PEO and chitosan increased the Vs of kaolinite, while xanthan gum exhibited counter-effects. Vs anisotropy (Vs−hh/Vs−vh and Vs−hv/Vs−vh) of polymer amended kaolinite was found to decrease. In addition, both salt- and polymer-modified kaolinite did not show Vs cross-anisotropy.

Vortex trapping and separation of particles in shear thinning fluids

Both enrichment and isolation of target particles from heterogeneous biological or chemical fluid samples are necessary steps in numerous particle-based analyses. We demonstrate, in this work, a vortex-based passive trapping and separation (by size) of particles in the flow of strongly shear thinning xanthan gum solution through a cavity microchannel. Our method utilizes the size-dependent fluid rheology- and inertia-induced lift forces that first align larger particles along the sidewalls of the straight uniform channel section and then drive them toward the microscale vortices developed inside the cavity because of the fluid shear thinning effect. It works effectively at the Reynolds number that is one order of magnitude smaller than the reported inertial vortex trapping for similar-sized particles. Our proposed particle trapping and sorting method in shear thinning fluids will be useful for applications processing medium-volume samples, which may fill the gap between the high-throughput inertial vortex-based passive technique and the usually low-throughput external force-based active techniques.

Asymmetric flows of complex fluids past confined cylinders: A comprehensive numerical study with experimental validation

Three non-Newtonian constitutive models are employed to investigate how fluid rheological properties influence the development of laterally asymmetric flows past confined cylinders. First, simulations with the shear-thinning but inelastic Carreau–Yasuda model are compared against complementary flow velocimetry experiments on a semidilute xanthan gum solution, showing that shear-thinning alone is insufficient to cause flow asymmetry. Next, simulations with an elastic but non-shear-thinning finitely extensible non-linear elastic dumbbell model are compared with experiments on a constant viscosity solution of poly(ethylene oxide) (PEO) in an aqueous glycerol mixture. The simulations and the experiments reveal the development of an extended downstream wake due to elastic stresses generated at the stagnation point but show no significant lateral asymmetries of the flow around the sides of the cylinder. Finally, the elastic and shear-thinning linear Phan–Thien–Tanner (l-PTT) model is compared with experimental velocimetry on a rheologically similar solution of PEO in water. Here, at low flow rates, lateral symmetry is retained, while the growth of a downstream elastic wake is observed, in qualitative similarity to the non-shear-thinning elastic fluids. However, above a critical flow rate, the flow bifurcates to one of the two stable and steady laterally asymmetric states. Further parameter studies with the l-PTT model are performed by varying the degrees of shear-thinning and elasticity and also modifying the confinement of the cylinder. These tests confirm the importance of the coupling between shear-thinning and elasticity for the onset of asymmetric flows and also establish stability and bifurcation diagrams delineating the stable and unstable flow states.

Hysteresis effect of propeller jet flows in viscoelastic fluids: Steady state flow patterns

Contrary to existing knowledge, the flow field showed a hysteresis effect when the rotational speed varied. The speed up operation in hysteresis range generates a semi-radial flow field, whereas the slow down operation causes an axial flow filed. Therefore, two stable flow fields can be formed at the same rotational speed and which one prevails depends on the flow history. The flow fields were measured using PIV and UVP, to explore the hysteresis range of four different xanthan gum solutions. The hysteresis range shifts toward higher rotational speed with increasing concentrations. The Reynolds number was failed to characterize the flow within hysteresis range but can be used for rotational speeds exceeding hysteresis range. The aim of this work was to introduce this phenomenon and to provide the first comparison between the two flow patterns and the fundamental for further researches dealing with the hysteresis effect in flow fields.

The effect of viscous soluble dietary fiber on nutrient digestion and metabolic responses Ⅱ: In vivo digestion process

Viscous soluble dietary fibers (VSDF) have received much attention for their potential role in energy regulation through the reduction of energy intake due to increased satiety. The aim of our study was to investigate the effects of low and high viscosities of xanthan and guar gum solutions on postprandial nutrient intake and plasma biomarkers of nutrient metabolism by an in vivo animal experiment. This study examined the effects of short-term and long-term intake of different VSDF on metabolism and physical condition in rats. On the third day the 4 h food intake (FI) after gavage of the high viscosity xanthan gum (HX) group was decreased from 13.07 g to 6.79 g and the blood glucose (BG) 30 min postprandial was lowered from 14.1 mmol/L to 7.9 mmol/L compared to Control. The amount of gastrointestinal chyme in the HX group was significantly higher than the other groups after 2 h of gavage. The long-term (3 weeks) consumption of VSDF reduced the rats' FI, body weight, fasting blood glucose, apparent protein digestibility, insulin and leptin concentrations, indicating that VSDF may reduce weight gain by inhibiting nutrient digestion. The long-term intake of VSDF increased the length of the small intestine. HX group had the lowest weight gain and nutrient digestion than the other groups.

Non-Newtonian Effects on Gas-Liquid Slug Flow in Micro-channel with T-junction Mixer

The length of liquid slug and gas bubble, gas bubble velocity and pressure drop of gas-liquid two-phase flow in a rectangular channel were measured using a high speed camera and a different pressure transducer. Water and Glycerol-solution as Newtonian liquids and Sodium carboxymethyl cellulose, Xanthan gum and Polyacrylamide-water solution as non-Newtonian liquids were used as the liquid phase, and N2 gas was used as the gas phase. The equivalent hydraulic diameter of the rectangular channel was 0.51 mm. The measured pressure drop data were compared with unit cell model, which applied to gas bubble pressure drop prediction proposed by Kurimoto et al. (2017). The following conclusions were obtained: (1) Different flow pattern was observed only in Polyacrylamide-water solution. (2) Frictional pressure drop on two-phase flow can associate with an effective viscosity of liquid. (3) Effects of elasticity of liquid on non-Newtonian two-phase two-phase flow should be accounted to predict accurately pressure drop.