Flow Behavior Index Research Articles

Producing high-colloidal-stability sesame paste: structural role of stone milling-modified protein.

Sesame paste faces issues with poor colloidal stability during storage, thereby affecting product quality and consumer experience. This study aimed to modify the proteins in sesame paste through stone milling and investigated the differences in stability produced in this environment, with the goal of addressing this issue. As the number of grinding times increased from one to three, the median diameter of sesame paste significantly decreased from 85 to 74 μm (P < 0.05), and the centrifugal oil separation rate dropped from 9.05% to 6.82%. Rheological measurements indicated an increase in the flow behavior index (n) from 0.51 to 0.61. Confocal laser scanning microscopy results revealed a more uniform co-distribution of protein and oil when ground thrice. The β-sheet content of the protein in sesame paste increased from 52.92% to 56.34%, with enhancements in surface hydrophobicity, hydrophobic interactions and emulsification of protein. When the number of grinding times increased to five, the particle size of the sesame paste was further reduced and the β-sheet content of the protein decreased to 51.00%, while the oil separation rate increased to 7.78%. Stone milling induces structural modifications in proteins, which in turn alter the internal structure of sesame paste, resulting in varying levels of oil separation at different grinding times. Among them, sesame paste ground thrice showed a 25% reduction in the oil separation rate and experienced minimal oil separation over 120 days, making it suitable for practical production. © 2024 Society of Chemical Industry.

Effects of fluid properties on coarse particles transport in vertical pipe

The mineral resources in deep-seabed are attracting extensive attention. A numerical simulation of particle transport in a vertical pipe for a deep-sea mining system is conducted using the CFD-DEM method. The effects of fluid density, fluid viscosity and rheological parameters of non-Newtonian fluids on the liquid-solid flow behavior in a vertical pipe are investigated. For Newtonian fluids, increasing the density or viscosity enhances the particles' performance in following the fluid and reduces the slip velocity, but also increases the pressure drop. The efficient lifting of particles can be facilitated by adjusting fluid density and viscosity, while considering factors such as energy consumption. For non-Newtonian fluids, an increase in either the flow behavior index n or the consistency coefficient k results in an increase in the fluid's apparent viscosity. This leads to an increase in the particle suspension capacity and local particle velocity, along with a decrease in local particle concentration.

Study on the Flow Characteristics of Non-Newtonian Drilling Fluid Through Vibrating Screen Meshes

Summary Composite screens are a critical component of drilling fluid shale shakers, and their performance directly affects the recovery efficiency of drilling fluid. This study focuses on the composite screens of shale shakers and simulates the flow of non-Newtonian drilling fluids through different structures of composite screens to investigate the impact of drilling fluid rheological parameters and screen compositions on screening performance. The research results indicate that the flow velocity of the drilling fluid is the highest while passing through the lower screen, and the turbulent kinetic energy (TKE) is at its maximum in the lower screen area, where energy dissipation is also the greatest. An increase in the rheological parameters of the four-parameter model drilling fluid generally increases the difficulty of passing through the screen, with the flow behavior index and viscosity coefficient having a particularly significant impact on the pressure drop coefficient. Compared with the plain composite screen, the herringbone composite screen and plain patterned composite screen have lower pressure drop coefficients, with the herringbone composite screen demonstrating the best screening performance. These findings provide theoretical references for flow analysis and structural optimization of shale shaker screens in drilling fluid applications.

Development of kiwi fruit leather incorporated with hydrocolloids and betacyanin microcapsules: Rheological behaviour and release kinetics of betacyanin

The kiwi fruit leather incorporated with betacyanin microcapsules was prepared using three hydrocolloids namely xanthan gum, gellan gum, and guar gum. The four-kiwi fruit puree prepared for the study were kiwi fruit puree without hydrocolloid (CP), with xanthan gum (XE), with gellan gum (EP), and with guar gum (UP). The influence of various hydrocolloids and temperatures on rheological properties of kiwi fruit puree was investigated using the Cross, Carreau, and modified Powell model. The apparent viscosity was decreased with increase in shear rate and rise of temperature. The incorporation of hydrocolloid also increased viscosity of prepared puree. Cross model (R2>0.989) found to fit the apparent viscosity with respect to shear rate. The flow behaviour index of four kiwi fruit puree samples was found to be less than one depicting pseudoplastic fluid with shear thinning behaviour. For dynamic rheology study in the frequency range of 1–60 rad/s, the storage modulus was higher than loss modulus at specific frequency that implies, elastic properties of puree were dominant over the viscous ones suggesting the weak gel-like network of kiwi fruit puree. The glass transition temperature of prepared kiwi fruit leathers ranged from 59-64°C. The in vitro betacyanin release from the leather sample was studied and Peppas-Sahlin model was observed to be one of the ideal model when compared with the other kinetic models. The development of kiwi fruit leather with hydrocolloids and betacyanin microcapsules represented a successful strategy to create a functional snack that combines health benefits with consumer-desirable sensory attributes.

Heat Transfer and Entropy Generation in Vibrational Flow: Newtonian vs. Inelastic Non-Newtonian Fluid

A computational method is employed to solve heat transfer and entropy generation within a circular pipe. The thermal boundary condition assumes a constant wall temperature, while viscosity is taken to be dependent on temperature. A power-law type shear-thinning fluid is utilized in the analysis, with sinusoidal vibration applied horizontally perpendicular to the flow direction. Temperature distributions across the pipe are illustrated. Additionally, the entropy generation rate over the entire fluid volume under vibration was examined, comparing the results between steady flow and vibrational flow for both types of fluids. It was found that radial mixing is more pronounced in non-Newtonian fluids as vibration increases the strain rate, which is higher for low Reynolds numbers. The research provides a quantitative analysis of heat transfer and entropy generation for both Newtonian and shear-thinning fluids at different Reynolds numbers. It was observed that the effectiveness of superimposed vibrational flow is limited, especially for low Reynolds numbers and flow behavior index characteristic of shear-thinning fluids.

Effect of solids concentration and operational variables on the performance of a geometrically optimized concentrator hydrocyclone employing a pseudoplastic fluid

The employment of hydrocyclones in thickening operations is an attractive option when compared to centrifuges and filters due to their low operating, maintenance, and acquisition costs. However, the performance of hydrocyclone separation is impaired as the concentration of solids and the viscosity of the suspension increases. Using geometric optimization techniques, the Federal University of Uberlândia developed one concentrator hydrocyclone named HC. When working with diluted and Newtonian slurries, the HC could generate a stream 45 times more concentrated than the one fed into it. In this study, the HC performance was evaluated when operating pseudoplastic fluids containing up to 10% solids by volume. The combination of the underflow diameter and vortex finder length with an adequate supply of pressure energy maintained the thickening potential of the HC even when the rheology of the fluid was changed. For different working suspensions, the HC hydrocyclone achieved a minimum water split to underflow of 5%, a maximum concentration ratio of 7.0, and a maximum efficiency of 49%. The encouraging results obtained by the HC validated the benefits of the geometric optimization, as they point to a significant advance in the thickening operation of non–Newtonian sludges with a flow behavior index greater than 0.5.

Hydrodynamic analysis of core annular flow with a viscoplastic lubricant

Core annular flow (CAF) with viscoplastic lubrication (VPL) is an attractive proposition for pipeline transportation of high viscous oil, slurries and suspensions. Past studies have performed stability analysis to show that the unyielded zone at the liquid-liquid interface stabilizes CAF by suppressing interfacial instabilities. However, an in-depth investigation of the flow hydrodynamics and the conditions which reduce the pumping power within stable CAF range using VPL has not been reported till date. Moreover, most of the studies have considered a Bingham Plastic liquid in the annulus. Only a single study (Usha & Sahu, 2019) is reported with Herschel-Bulkley (HB) liquid in the annulus that considers the entire annulus to be in the shear zone. Another experimental study (Huen et al., 2007) has demonstrated stable core annular flow with a shear thinning core and a HB annulus. In the present work, we analyze viscoplastically lubricated CAF for a Newtonian core where the yield stress annular liquid is described by the generalized HB model. The simplified analysis can predict CAF stability and is further explored to (i) assess the efficacy of VPL for stable energy-efficient oil transportation, and (ii) enhanced throughput without clogging during suspension transportation. The analysis, validated against data from literature, unravels the influence of rheological properties on flow hydrodynamics. We note that an annular liquid with low flow behavior index, n and yield stress, τy lowers pumping power, but the yield stress should be sufficient to form a plug zone at the interface for suppressing instabilities and stabilizing CAF. For viscous oil, a phase diagram in dimensionless coordinates (Reynolds number of the oil core and Herschel-Bulkley number of the annular liquid, both expressed at the inlet conditions) suggests the range of operation where an available HB liquid can serve as an effective annular lubricant for energy-efficient transportation.

A modular, low-field magnetic resonance design with pre-polarization for characterizing flows

We have recently demonstrated a magnetic resonance method using variable τ spin echoes to simultaneously determine both the average velocity and flow behavior index in a variety of pipe flows. In this work, we present a new, modular, low-field design built specifically for use with our methodology. The design is based on low-cost ceramic magnets. It consists of a sensor built using a pitched magnet arrangement in combination with several modular pre-polarizing units to facilitate a controlled pre-polarization length for measurements on flows that require a significant amount of time in a magnetic field to become polarized (e.g., aqueous solutions). Here, measurements made with this design are shown for a range of flow rates that span the laminar regime and into the turbulent regime.

Surrogate-assisted multi-objective Bayesian optimization for improved rheological design of bioinks

Extrusion bioprinting is a popular biofabrication technique for creating viable biological constructs with applications ranging from regenerative medicine and cancer research to therapeutics screening. A primary challenge within extrusion bioprinting lies in preserving cell viability and function amidst the shear forces generated during extrusion. Therefore, the formulation of shear-thinning bioinks with tailored flow properties is essential to minimize shear stress accumulation during printing. However, this task is complex, as the bioink’s flow properties are contingent upon numerous factors, including but not limited to the polymer concentration, spatial cell density in the bioink, molecular weight of the polymer, and the nozzle’s geometry. The current methods for adjusting flow properties are heuristic, posing challenges to the rapid development models and automation of the bioprinting workflow. In this study, we introduce a Gaussian Process-based multi-objective Bayesian optimization framework that rapidly identifies Pareto-optimal flow property values to minimize hydrodynamic shear stresses during extrusion. The optimization focuses on four flow parameters, minimum viscosity, maximum viscosity, consistency index, and flow behavior index from the power-law model of shear-thinning fluids alongside the nozzle outlet diameter. Following an initial set of 24 experimental runs, our sequential design approach required 21 iterations to achieve convergence on a set of flow parameters that meet the Pareto optimality criteria. The presented strategy, which integrates physics-based numerical models with data-driven optimization models, emerges as a tool for the rapid fine-tuning of bioink flow behaviors. The multi-objective framework also sets the stage for future exploration into cell viability and functional outcomes post-bioprinting.

A simple model incorporating foam rheology to quantify foam penetration behaviour in EPB shield tunnelling

Fulfilling the role of a soil conditioner, foam plays a pivotal role in Earth Pressure Balance (EPB) shield tunnelling by enhancing soil properties such as lowering permeability and increasing flowability. This study introduces a macro-model designed to quantify foam penetration behaviour in saturated sand, utilising rheological properties. To validate this model, experiments were conducted to replicate the foam penetration behaviour. Six sand beds characterised by varying particle sizes, along with foam having an expansion ratio of fifteen, were employed for penetration tests under different hydraulic conditions utilising a sand column device. The rheological profile of the foam is described by the power-law model, as also found by rheometer tests, although with different parameters. The flow behaviour of foam within the sand column conforms to the flow equation that governs power-law fluids in porous media. The developed model effectively predicts the foam penetration process under varying hydraulic conditions compared with the experimental results. Furthermore, the fitting results of the experimental data indicate that the flow behaviour index of the foam remains approximately 0.09 across all tests, regardless of the type of sand used. In contrast, the model-derived generalised permeability coefficient strongly correlates with the effective particle size (d10) of the sand bed. Overall, the model effectively quantifies the foam penetration behaviour, accounting for changes in infiltration velocity and pore water pressure, which is essential for understanding the transfer of support pressure in EPB shield tunnelling.

A numerical investigation of laminar planar hydraulic jump in Herschel-Bulkley fluid

Laminar planar hydraulic jump during viscoplastic liquid flow in a horizontal channel is investigated through experiments and numerical simulation using Herschel-Bulkley (HB) model. The simulations are performed using the phase-field method with Papanastasiou regularization parameter and validated against experimental results. Both experiments and simulations show the free surface height to gradually increase upstream of jump and recede after the jump with a remarkable increase in free surface height and surface waviness at the jump. The model further reveals that an increase in any of the rheological parameters [yield stress (τo) flow behaviour index (n) and flow consistency index (k)] keeping the other properties constant increases film thickness. This increases jump strength and shifts jump towards the entry. However, each parameter influences free surface profile and jump characteristics in a different way. While a higher τo suppresses the development of the shear zone and results in a thicker plug zone, a higher n increases shear zone thickness and decreases the plug zone thickness. On the other hand, a higher k increases both shear and plug zone thickness. The steady state fully developed self-similar velocity profile is independent of k and depends on τo and n. Different jump types, obtained from simulations, are presented as phase diagrams in non-dimensional coordinates for a generalised approach.

The evolution of granular surface structure and functional properties in rice starch during grain filling

The developmental changes in the granular surface structure and functional properties of starch during the entire grain filling period of rice (around 40 days) were investigated. The specific surface area of rice starch significantly decreased firstly then stabilized during growth due to increasing granular size. The pore volume decreased from 5.40 cm3/g at 6th day after anthesis (DAA-6) to 3.02 cm3/g (DAA-46). More starch granule-associated proteins (SGAPs) accumulated on the surface and in channels. Swelling power decreased by 46 %, whereas the flow behavior index (n) decreased by 32 % in upward curve during starch development from DAA-6 to DAA-30. Tan δ first dropped then remained steady at DAA 22–34 and lightly rebounded at the final stage, indicating that starch in the middle stage tended to have greater viscoelastic gel behavior at all sweeps. Mature starch showed lower in vitro hydrolysis rate and exhibited stronger enzymatic resistance. The results showed that granular surface features of rice starch may be an essential factor in determining rheological behavior and resistance to hydrolysis.

Assessment of rheological, qualitative and antioxidant characteristics of enriched peanut butter with date paste through shelf-life stability

Over the years, concentrated efforts have been directed toward the improvement of desirable characteristics and attributes in peanut butter. This study examined the effect of rheological, antioxidant and qualitative characteristics of optimum peanut butter (including date paste and lecitin) during shelf-life. The results showed that the presence of date paste along with lecithin in optimum peanut butter improved the overall characteristics of peanut butter, including the physicochemical, microbial, mechanical, and sensory properties, compared to the control. Moreover, shelf-life had the most effect on reducing the emulsion stability, cohesiveness, antioxidant properties, and overall acceptance. In addition, the flow behavior of the emulsions was examined through the Herschel-Bulkley model using the parameters of determination coefficient, R2, flow behavior index, n, and consistency coefficient, K (Pa.sn). The presence of date paste in enriched peanut butter results in the creation of a colloidal structure among the peanut particles. This structure traps the oil, preventing it from leaving the peanut paste texture during shelf-life.

Effect of Olivine, Barite and Calcium Carbonate on Cutting Carrying Capacity of Water-Based Drilling Fluids

Introduction: In this study, the effect of different weighing material such as olivine, barite and calcium carbonate on cutting carrying of water-based drilling fluids was investigated. Initially, characterization studies were performed for the additive materials. Method: Then, spud type muds were prepared with bentonite and the weighing materials were added at different rates ranging from wt.1-6%. After the sample preparation, mud weight, 600 and 300 rpm dial reading, plastic viscosity, yield point, flow behavior index and power law consistency factor values were measured/calculated. Result: With these results, cutting carrying index of the muds was calculated and the effect of the additive materials was compared. According to the results, it was determined that the barite added muds had better cutting carrying capacity than others and the calcium carbonate added muds showed worse cutting carrying capacity. Optimal CCI results were obtained from O-5 as 3.7869 and, from B-6 as 5.9417 and from C-4 as 2.7113. Conclusion: Results of this study show that olivine can be used as low additive ratios in drilling muds to clean the hole.

Combined electroosmotic and pressure driven flow through soft nanochannel grafted with partially ion-penetrable polyelectrolyte layers

ABSTRACT This study explores the coupled effects of pressure-driven and electroosmotic flows in a soft nanochannel filled with non-Newtonian ionised liquid, where the inner walls are coated with a polymer layer. The ion partitioning effect occurs due to the Born energy, arising from the dielectric permittivity difference between the polyelectrolyte medium and the ionised liquid. The model incorporates the nonlinear Poisson-Boltzmann equation, the modified Darcy-Brinkman equation in the polyelectrolyte layer (PEL), the Cauchy momentum equation in the electrolyte domains and the continuity equation for incompressible fluids. Using the Debye-Hückel approximation for analytical results, the study validates numerical findings. The study considers the no-slip boundary condition on the walls and examines the impact of volume charge density of PEL, bulk electrolyte concentration, non-Newtonian fluid rheology and polymer layer characteristics and applied pressure gradient on flow modulation and ionic transport in the nanochannel. We provide rigorous mathematical results showing how electrohydrodynamic factors like charged PEL, flow behaviour index, EDL thickness, ion partitioning parameters, Debye-Hückel parameter and softness parameters influence the strength of the potential and the total flow modulation. We illustrate ion selectivity in the soft nanochannel and the friction factor across its walls, considering ion partitioning effects.

Rheological, textural, and swallowing characteristics of xanthan gum-modified Riceberry porridge for patients with dysphagia.

The incidence and prevalence of dysphagia worldwide are increasing yearly requiring a change in food texture to avoid malnutrition, dehydration, or sever complications. Riceberry porridges fortified with protein hydrolysate (1.5%), bio-calcium (589 mg), and thickened with xanthan gum (XG) of varying concentrations (0%, 0.255, 0.50%, 0.75%, 1.0%, and 2.0%) showed suitability for use in enriching diets of these patients. Porridges were examined using specified tests from the International Dysphagia Diet Standardization Initiative (IDDSI) and National Dysphagia Diet (NDD), and coupled with rheological, textural analyses, in vitro swallowing simulator and sensory analysis performed by a trained panel. Porridges with 0%-0.25% and 0.50%-2.0% XG were classified as IDDSI level 3 and 4, respectively, and apparent viscosities of porridges showed samples with XG displayed shear thinning behavior beneficial for patients with dysphagia. Increasing XG concentrations increased the consistency coefficient and decreased the flow behavior index (p < .05) with positive correlation of XG concentration with textural properties including firmness, consistency, cohesiveness, adhesiveness, and stickiness values. The relationship between instrumental measurements, in vitro and in vivo swallowing behavior showed high correlations with regards to XG concentration (r = .995). The findings indicate Riceberry porridges containing XG have significantly improved textural properties over those without XG for patients with dysphagia.

Effect of xanthan gum on stability and rheological behavior of O/W emulsion

Oil-in-water emulsions were prepared by homogeneous emulsification using glycerol stearate (and) PEG-100 stearate (A165) as emulsifier and xanthan gum (XG) as thickener. The effects of oil and XG content on the stability and flow behavior of emulsion were studied by polarizing microscope and rheometer. The hydrogen bonding interaction between xanthan gum molecules was studied by molecular dynamics simulation, and then the interaction between xanthan gum and emulsifier was further studied. The results showed that when there is no xanthan gum and the emulsifier content is 3%, the oil content increased, the particle size decreased. When the oil content is constant, the emulsion particle size decreases at first and then increases with the XG content increasing, which is due to the accumulation of XG and emulsifier on the oil-water interface, and the interfacial film thickens. The flow behavior of O/W emulsion can be described by a power law function. The emulsion without XG is Newtonian fluid at low oil content, and when the oil content increased, it was transformed into non-Newtonian fluid. The viscosity and consistency index increased with the increase of XG, which is due to the hydrogen bond between XG and emulsifier. However, the flow behavior index decreased greatly, the degree of shear thinning of emulsion enhanced. XG increased the viscosity of the mobile phase, under shear force, the deformation degree of droplets and the degree of shear thinning were different. This study can provide a reference for further regulating the stability and flow characteristics of skin care emulsion.

Comparative Study of Heat Transfer and Flow Friction in Plate Heat Exchangers with CarboxyMethyl Cellulose and Sodium Alginate

Abstract: Study of Plate heat exchanger (PHE) with power law fluid is a very interesting topic now a days as there is improvement of thermal performance of heat exchanger. Power law fluids show complex flow behavior due to its rheological properties. The parameters which differ these power law fluids from Newtonian fluids are rheological properties like flow behavior index and power law index. Hence flow behavior index and power law index are the two parameters which affect the heat transfer rate. Now to enhance rate of heat transfer we should know how Nusselt number changes with change in flow behavior index and power law index. Hence the aim of present study was to observe how Nusselt number and friction factor changes with change in flow behavior index and power law index. For this purpose thermal performance of PHE have been studied with CorboxyMethyl Cellulose (CMC) and sodium alginate as a cold fluids. Comparison of Nusselt number and friction factor of CMC and sodium alginate have been done. It was observed that Nusselt number for CMC solution was more compared to sodium alginate solution with less friction factor than sodium alginate.

Complementary Foods Formulated from Orange-flesh Sweet Potato, Soybean, and Date Palm Flour Blends Improves the Proximate, Rheological and Sensory Properties of Children’s Formulas

This study evaluated the proximate, rheological and sensory properties of complementary foods produced from orange flesh sweet potato, soybean and date palm flour blends. Complementary foods were produced from orange flesh sweet potato (OFSP), soybean and date palm flour blends. The samples were formulated by material balancing with all samples having 16% protein/ 100g. The samples were coded as CON, CFA, CFB, CFC, CFD and CFE with sample CON being the control. The samples were subjected to rheological and sensory analysis using standard method. Their proximate composition were; moisture (2.51-7.38%), ash (2.27-3.02%), fibre (2.11-4.22%), fat (9.13-10.11%), protein (15.12-16.11%), and carbohydrate (63.06-65.01%). Rheological properties of the gruels were as follows; consistency index (m) (90.57-186.21 Nsn/m2), Flow behaviour index (n) (0.256-0.411), Coefficient of regression (r2) (0.9765-0.9928) and Standard error (0.318-0.405). The sensory attributes gave the following results; appearance (7.77- 8.07), aroma (7.20-8.63), taste (6.80- 8.23), mouth feel (6.87- 8.27), and overall acceptability (6.80- 8.33) and these results when interpreted on appoint hedonic scale. Higher scores generally indicated better sensory attributes and overall acceptability of the food formulation which was observed in sample CFB and CON. There were significant differences between most of the bread samples at (p&lt; 0.05).

Comparison of four rheological models for estimating viscosity and rheological parameters of microwave treated Basil seed gum

Dispersion of Basil seed gum has high viscosity and exhibits shear-thinning behavior. This study aimed to analyze the influence of microwave treatment (MT) at various time intervals (0, 1, 2, and 3 min) on the viscosity and rheological behavior of Basil seed gum dispersion (0.5%, w/v). The finding of this study revealed that the apparent viscosity of Basil seed gum dispersion (non-treated dispersion) reduced from 0.330 Pa.s to 0.068 Pa.s as the shear rate (SR) increased from 12.2 s−1 to 171.2 s−1. Additionally, the apparent viscosity of the Basil seed gum dispersion reduced from 0.173 Pa.s to 0.100 Pa.s as the MT time increased from 0 to 3 min (SR = 61 s−1). The rheological properties of gum dispersion were successfully modeled using Power law (PL), Bingham, Herschel–Bulkley (HB), and Casson models, and the PL model was the best one for describing the behavior of Basil seed gum dispersion. The PL model showed an excellent performance with the maximum r-value (mean r-value = 0.942) and the minimum sum of squared error (SSE) values (mean SSE value = 5.265) and root mean square error (RMSE) values (mean RMSE value = 0.624) for all gum dispersion. MT had a considerable effect on the changes in the consistency coefficient (k-value) and flow behavior index (n-value) of Basil seed gum dispersion (p < 0.05). The k-value of Basil seed gum dispersion decreased significantly from 3.149 Pa.sn to 1.153 Pa.sn (p < 0.05) with increasing MT time from 0 to 3 min. The n-value of Basil seed gum dispersion increased significantly from 0.25 to 0.42 (p < 0.05) as the MT time increased. The Bingham plastic viscosity of Basil seed gum dispersion increased significantly from 0.029 Pa.s to 0.039 Pa.s (p < 0.05) while the duration of MT increased. The Casson yield stress of Basil seed gum dispersion notably reduced from 5.010 Pa to 2.165 Pa (p < 0.05) with increasing MT time from 0 to 3 min.