Dynamic Viscosity Data Research Articles

Characterization of the dynamic viscosity of cell cultures and its effect on mixing performance in a spinner flask bioreactor

Computational fluid dynamics (CFD) models have been developed to simulate cell culturing bioreactors but assume water-like viscosity properties due to significant data gaps. This study characterized the dynamic viscosity of HEK-293 cell cultures and evaluated its effect on mixing performance in a spinner flask bioreactor. Viscosity measurements indicated that the cell culture media, media with microcarriers, and cell cultures presented shear thinning behaviors within the measured shear rate range of 1–100 s−1. The viscosity also increased with the microcarrier concentrations and growth of cell culture. The CFD model, incorporating dynamic viscosity data, showed that shear stress and Kolmogorov length profiles are significantly influenced by microcarrier concentrations and cell culture growth. Higher microcarrier concentrations led to higher average shear stress and Kolmogorov values. The cultured HEK-293 cells after seven days of growth also had higher average shear stress and Kolmogorov values than at the day of seeding, indicating an impact caused by the cells’ metabolism and biomass. Overall, the results indicated that assuming water-like properties underestimates shear stress and Kolmogorov length scales, especially at zones of lower shear rates due to the observed shear thinning behavior. Thus, careful monitoring of dynamic viscosity of cell cultures and proper control of mixing parameters are critical to deliver the desired mixing conditions for optimized cell growth especially during scale-up production operations.

Thermophysical properties: Viscosity, density, and excess properties of 2-propanol and n-Decane mixtures from 283.15 K to 343.15 K under atmospheric conditions

To study the effects of temperature as well as molecular interaction of a fluid system on the thermophysical properties of 2-propanol and n-Decane binary mixture, the density (ρ), dynamic viscosity (η), speed of sound (u), and refractive index (nD) of pure 2-propanol and n-Decane, along with their binary mixtures, were experimentally measured across the entire compositional range at temperatures from 283.15 to 343.15 K and atmospheric pressure. These experimental measurements helped in the evaluation of various thermophysical properties, such as excess molar volume (vE), coefficient of thermal expansion (αE), and isentropic compressibility (κsE). The experimental dynamic viscosity (η) and density (ρ) data were used to evaluate kinematic viscosity (v) and Gibbs free energy (ΔG) of flow with an equation based on Eyring's absolute state theory, and their corresponding excess properties. The excess properties of the binary mixtures were correlated using a Redlich-Kister type polynomial equation via the least-squares regression method, with fitting parameters determined for the binary system. Moreover, the Prigogine–Flory–Patterson theory (PFP) was utilized to identify the primary molecular interactions contributing to the excess molar volume at 293.15, 308.15, and 323.15 K for the binary mixtures. Additionally, the capability of the Eyring-NRTL model was tested to predict the viscosity as well as vapor-liquid equilibrium (VLE) of the binary system, and the correlated model results agreed with literature data.

Density, thermal expansion, dynamic viscosity of halogenated arenes

Purpose. Experimental study of the density, thermal expansion and dynamic viscosity of halogenated arenes at temperatures from 293.15 to 343.15 K and atmospheric pressure 97.992 kPa.Methods. Density was determined by the pycnometric method, viscosity by the capillary method. A quartz pycnometer type PZh2 with a nominal capacity of 10 ml and a glass capillary viscometer type VPZh-2 with a nominal capillary diameter of 0.34 mm were used. The mass of liquids was measured using an electronic scale VSL-200/0.1A with a division value of 0.0001 g. Numerical methods were used to process the experimental results.Results. Experimental data were obtained on the density, coefficient of volumetric thermal expansion and dynamic viscosity of liquid o-xylene, ethylbenzene, fluorobenzene, chlorobenzene, bromobenzene, toluene, o-fluorotoluene, mfluorotoluene, p-fluorotoluene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, 2,4-dichlorotoluene, 2,6-dichlorotoluene. Density and dynamic viscosity data are approximated by a third-degree polynomial. Data on the coefficient of volumetric thermal expansion are obtained from approximated measured density data. The maximum estimate of the measurement error for density was 0.13 %, for dynamic viscosity – 3.5 %. The maximum calculation error for the coefficient of thermal expansion is estimated at 3 %.Conclusion. Mathematical processing of the obtained experimental data on density and dynamic viscosity made it possible to obtain analytical relations in the form of power polynomials that allow calculating the values of these quantities at any temperature from the studied temperature range and atmospheric pressure with an error not exceeding the error of experimental determination. The calculated values are in good agreement with the data provided in the reference and scientific literature. The experimental data obtained complement the information on the properties of some of the liquids under consideration, for which the dependences of density and viscosity on temperature are poorly understood. The substances under study are used in various sectors of the economy and are therefore technically important liquids. The measurement results can be used in condensed matter physics, for the analysis of liquid hydrocarbons, and can be useful in the chemical industry.

Combined thermodynamic and theoretical study on ether-functionalized ionic liquid mixture systems of [MOEmim][TFSI] with ACN/GBL

Ether-functionalized ionic liquids (ILs) have a higher fluidity and are widely used in a variety of applications due to the introduction of the ether group. In order to better understand the relationship between properties and internal interactions of ether-based ILs, we prepared two ether-functionalized ILs 1–2-methoxyethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([MOEmim][TFSI]) with acetonitrile (ACN) or γ-butyrolactone (GBL) mixture systems, and investigated the changes of their thermodynamic properties and internal interaction behaviors over the entire concentration range. First, the thermodynamic properties such as dynamic viscosity, density and electrical conductivity of the two mixture systems were measured from 288.15 K to 343.15 K. The excess molar volume (VE), and viscosity deviation (Δη) were calculated by using the measured experimental density and dynamic viscosity data, which can provide microscopic information on the interactions. Further, the intermolecular interactions of the mixture systems were evaluated by density functional theory (DFT) calculations. The sigma–profile (σ–profile) provided insight into the hydrogen bonds (H-bonds) and molecular surfaces interactions. We also used molecular dynamics simulations (MD) to study ILs mixtures in many different solvent concentrations, thereby providing a microscopic and macroscopic characterization of fluid structure, molecular aggregation, and intermolecular forces.

Evaluating the Effectiveness of Proportional Nodes Method in Curve Fitting for Surfaces: Application to Data of Dynamic Viscosity of Ammonia-Water Solution

This study used the proportional nodes method, a novel curve fitting approach to correlate data for dynamic viscosity of ammonia-water solution. The approach integrates polynomial equations, generated at various temperatures, with those calculated at selected mole fraction nodes. These nodes are scaling factors that account for variations in dynamic viscosity at different temperatures at selected mole fractions. The accuracy of the polynomial equations ensures a high degree of fitting accuracy. The proportional nodes, computed systematically, were integrated into a robust and highly accurate polynomial model to generate correlations that fit the data for the surface. This model exhibited minimal average percentage differences between predicted and actual viscosity values (±0.2614293 for temperature range, 273.15K to 303.15K and ±1.11 for temperature range, 303.15K to 423.15 K), indicating a high level of predictive accuracy. The proportional nodes method offers a significant contribution to both academic research and industry. It provides a more precise and adaptive model for predicting the dynamic viscosity of ammonia-water solution, which is critical for optimizing and designing various industrial applications, including refrigeration systems.

Some experimental and theoretical studies of diethylene glycol diethyl ether and 2-alkanol mixtures

Experimental density and dynamic viscosity data for the diethylene glycol diethyl ether +2-alkanol (C3 to C6) mixtures have been published at 293.15 K, 303.15 K, 313.15 K, and 323.15 K and at pressure of 0.1 MPa. Excess molar volume and deviation in dynamic viscosity were obtained from experimental data and correlated with Redlich–Kister equation, from the values obtained, the interaction forces were studied. Perturbed chain-statistical associating fluid theory equation of state was used for modeling the density for pure fluids and mixtures. Free volume theory coupled to Perturbed chain-statistical associating fluid theory equation of state was used to modeling the viscosity of pure fluids and mixtures; in the case of binary mixtures, we proposed a simple mixing rule and used the Pourabadeh et al. mixing rule. Good results in the prediction and correlation of experimental liquid density and dynamic viscosity for binary mixtures were obtained, 0.12% and 2.28%, respectively.

Viscosities of 1,2-DAP + alkyl acetates binary liquid mixtures at T = 298.15–318.15 K: Theoretical interpretation by Graph theoretical approach (GTA) and Bloomfield and Dewan (BFD) model

The liquid mixtures are used as a solvent in most of the natural systems and chemical processes. Therefore, the physicochemical properties of liquid mixtures at different compositions and at different temperatures have a significant role in the optimization of chemical processes. In the present report, the dynamic viscosity (η) of 1,2-DAP (1,2-Diaminopropane) (1) with AAc (alkyl acetates) (C1-C4) (2) were measured at different temperatures (T = 298.15 to 318.15 K) at pressure 0.1 MPa. Deviation in dynamic viscosity, Δη, and excess Gibbs free energy of activation, G∗E, for these binary mixtures were calculated from measured dynamic viscosity data and fitted to Redlich-Kister polynomial equation (R.K.). Δη data were examined in terms of the Bloomfield and Dewan (BFD) model and Graph theoretical approach (GTA) to study the intermolecular interactions in binary mixtures. Further, different correlation like Hind-McLaughlin-Ubbelohde, Bingham, Arrhenius, Kendall, Heric-Brewer, Kendall-Monroe, Tamura-Kurata, Lulian, Grunberg-Nissan, Krishnan-Laddha Frenkel, Katti-Chaudhari, Heric and McAllister were used to correlate η values.

Thermophysical properties of 2-amino-2-methylpropan-1-ol + alkanol mixtures: Investigation of molecular interactions by insight of FT-IR spectroscopy

We report the experimental data of dynamic viscosity (η) and ultrasonic speed (u) for 2-amino-2-methylpropan-1-ol (AMP) (1) + alkanol (C1-C3) (2) at T = (298.15–318.15) K and 0.1 MPa pressure. The derived excess (or deviation in) properties like dynamic viscosity (Δη), speed of sound (Δu) and excess isentropic compressibility (κSE) were regressed through Redlich-Kister polynomial equation. The Δη values were analyzed in terms of an Ab-initio approach, to study the intermolecular interactions between the binary components. Our analysis indicated that compared to propanol, methanol and ethanol interact strongly with AMP and 2-propanol exhibited the weakest interactions with AMP owing to steric hindrance by branched propyl group. In addition, viscosity (η) values and ultrasonic speed (u) data were analyzed using the various thermodynamic models/correlations that agreed well with our experimental data. Furthermore, we analyzed the FT-IR spectra of pure components and their binaries and observed prevailing hydrogen bonding interactions between the N-atom and OH-group of AMP with the OH-group of alkanol. Our findings highlight the great bonding capability of AMP with lower alkanol due to its small size and linear shape and can provide information on designing effective binary mixtures (blended) solvents based on AMP for CO2 absorption.

Efficient machine learning model to predict dynamic viscosity in phosphoric acid production

The rheological behavior of the phosphoric acid slurry, during the production process, strongly depends on its dynamic viscosity. Controlling this property limits P2O5 losses, minimizes energy consumption and ensures optimal flow conditions. Thus, reliable simulation tools predicting the viscosity property are needed for analysis and process optimization. To this end, three machine learning (ML) methods: single-layer artificial neural network (ANN), gradient boosting (GB) and random forest (RF), were tested using 456 data of dynamic viscosity at different solid content, shear rate and temperature, obtained from industry. The performance of these models was evaluated and compared using diverse precision metrics. The GB has shown to be the outperforming model with determination coefficient greater than 99%, and Root Mean Squared Error lower than 0.750, on both training and validation datasets. Based on the importance of the explanatory variables, all models agree on the large effect of solid content on dynamic viscosity, followed by shear rate, then temperature. The GB relative partial dependence diagram made it possible to deduce operating intervals for the solid content of the pulp to be fed to the phosphoric acid reactor, leading to optimal flow of the suspension at the level of the attack and maturation units.

Reporting of experimental viscosity data and modeling of transport properties of 1,1,1,3,3,3-hexafluoro-2-methoxypropane (HFE-356mmz) using extended corresponding states (ECS) and residual entropy scaling (RES) technique

As a novel low GWP working fluid 1,1,3,3,3-hexafluoro-2-methoxypropane (HFE-356mmz) is regarded as a promising candidate for high-temperature heat pumps and organic Rankine cycle. Recently, the experimental kinematic viscosity and thermal conductivity data of HFE-356mmz were published in the literature. However, at the time of that publication it was not possible to develop any mathematical model of the transport properties due to unavailability of an equation of state. In this work, we report dynamic viscosity data of HFE-356mmz together with mathematical models for dynamic viscosity and thermal conductivity using the extended corresponding states (ECS) and the residual entropy scaling (RES) technique. With R134a used as the reference fluid for ECS method, the transport shape factors and the other adjustable parameters were calculated by utilizing latest multi-parameter Helmholtz-energy-explicit-type equations of state for HFE-356mmz. Furthermore, slight modification of the original RES method has been adopted that removes the implicit dependency on the tuned ECS method. By using the adjustable parameters, the tuned ECS and RES transport equations can represent the experimental data within reported uncertainties. The average absolute deviations (AAD) for viscosity and thermal conductivity were found to be 0.85% and 0.76% using the tuned ECS and 0.83% and 0.44% using the modified RES method respectively.

Alkane-based eutectic phase change materials doped with carbon nanomaterials.

Cold thermal energy storage is an issue of increasing importance on a global scale particularly in the format of passive thermal protection. This study presents three eutectic Phase Change Materials (ePCMs) composed of n-alkanes, which provide passive temperature control (their operation is automatically induced by exceeding the limit temperature without the need for a control system) around 4 °C (277.2 ± 2 K) and are chemically neutral. The solid-liquid equilibrium (SLE) in the following binary systems was investigated: {n-tetradecane + n-heptadecane}, {n-tetradecane + n-nonadecane}, {n-tetradecane + n-heneicosane}, allowing the determination of two ePCMs with enthalpies close to 220 J g-1 and one significantly lower (155.5 J g-1). Moreover, two solid-liquid-liquid equilibrium (SLLE) phase diagrams were determined for systems: {n-tetradecane + 1,6-hexanediol} and {n-tetradecane + 1,12-dodecanediol}. In addition, the work provides a systematic analysis of the problem of designing ePCMs with specific properties and the aspects that need to be considered. The possibility of predicting the parameters of eutectic mixtures using the UNIFAC (Do) equation and the equation of ideal solubility was verified. A method for predicting the enthalpy of melting of eutectic was also proposed and confronted with the results of DSC analysis. Thermodynamic studies have been supplemented with measurements and correlation of experimental data of ePCMs density and dynamic viscosity as a function of temperature. The final issue is the improvement of the thermal conductivity of paraffins by the addition of nanomaterials such as Single Wall Carbon Nanotubes (SWCNTs), Expandable Graphite (GIC) or Expanded Graphite (EG). The possibility of forming a long-lasting composite material composed of ePCMs and 1 wt% of SWCNTs with a thermal conductivity significantly higher compared to pure ePCMs has been proven via stability testing under operating conditions.

Simultaneous Viscosity and Density Measurements and Modeling on Liquid Undecane, Dodecane, Tridecane, and Tetradecane up to 50 MPa

In this study, simultaneous experimental measurements of dynamic viscosity and density of four Newtonian liquids (undecane, dodecane, tridecane, and tetradecane) were performed in the pressure range from 1.99 to 50.01 MPa, along five isotherms between 298.15 and 353.16 K. The dynamic viscosity and density were determined using the capillary flow technique and a vibrating tube densimeter, respectively. The viability of the methods used was verified through the experimental measurements of the viscosity and density of ethanol and its comparison with data published in the international literature, resulting a maximum deviation of 1.25% for viscosity and 0.58% for density. The relative combined expanded uncertainty (k = 2) for the experimental measurements was estimated to be 1.4% and 0.2% for dynamic viscosity and density data, respectively, considering the impurities of the chemical compounds. Also, two empirical models were used to represent the experimental data reported in this work; for the dynamic viscosity, a maximum deviation of 0.5% was found, while, for density, a maximum deviation of 0.11% was obtained. From density data and using the empirical model, the isothermal compressibility and isobaric thermal expansivity were evaluated under the reported conditions.

Volumetric and transport properties of switchable-hydrophilicity solvent systems: N,N-Dimethylbutylamine, water and carbon dioxide

Switchable-hydrophilicity solvents (SHSs) are an emerging class of solvents with switchable phase behavior. They can be used as a substitute for volatile solvents and can be removed from organic products without distillation. However, the detailed physical properties data of SHSs are still very scarce in the literature. In this work, the experimental values densities, dynamic viscosities, refractive indices as well as conductivities of switchable hydrophilicity solvent (SHS)systems (N,N-Dimethylbutylamine (DMBA), water, and carbon dioxide) are investigated at temperatures (283.15, 288.15, 293.15, 298.15, 303.15 and 308.15) K and at atmospheric pressure. VLE of the CO2 loaded DMBA solutions are measured at 298.15 K over the partial pressure range of carbon dioxide from 17.0 to 98.0 kPa. Density data have been used to calculate the apparent molar volumes (Vϕ), limiting apparent molar volumes (Vϕ0) and limiting partial molar expansivity of solute (Eϕ0). The Jones-Dole coefficients B, the Gibbs free energies of activation of viscous flow per mole of solvent (Δμ10≠) and per mole of solute (Δμ20≠), entropies (ΔS20≠) and enthalpies (ΔH20≠) of activation of viscous flow were calculated from experimental viscosity data and discussed in terms of transition state theory. The Walden's product was calculated from the conductance and dynamic viscosity data. The results are valuable sources of information on the design and development of SHSs for novel industrial applications.

Synthesis, measurement, and correlation study of physico-chemical properties of diethanolamine glycinate ionic liquid as a solvent for CO2 capture units

Amino acid-functionalized ionic liquids (ILs), known as environmentally green non-molecular solvents, have been particular interested in the CO2 capture processes due to their unique physico-chemical properties. Proper development of CO2 capture processes utilizing amino-functionalized ILs, requires the exact determination of the ILs’ physico-chemical properties. In this paper, a novel amino acid-functionalized IL, namely diethanolamine glycinate ([DEA][GLY]), was synthesized and then characterized via Nuclear Magnetic Resonance (H NMR) and Fourier Transform Infrared (FT-IR) spectroscopy analysis. The density, dynamic viscosity, and surface tension were experimentally measured over the temperature range of 303.15–323.15 K and a wide verity of IL concentrations from 5 to 25 wt% of IL aqueous solution under atmospheric pressure. Furthermore, simple but reliable correlations with minimum input variables were implemented to model the density, dynamic viscosity, and surface tension data of the binary mixtures of [DEA][GLY] + H2O in terms of temperature and composition. Regarding the statistical criteria, it was indicated that the two-descriptor-based models could well describe the effect of temperature in different concentrations of the glycine amino acid-functionalized IL compared with those single temperature-dependent correlations.

Semi-empirical correlations and an artificial neural network for liquid dynamic viscosity of low GWP refrigerants

In this work, simple semi-empirical correlations to describe the temperature and the pressure dependence of the dynamic viscosity of low GWP refrigerants, namely HydroFluoroOlefins (HFOs) and HydroChloroFluoroOlefins (HCFOs), in the liquid phase are presented. Firstly, the experimental liquid dynamic viscosity data available in scientific literature and databases were collected and statistically analyzed. From the data collected for low pressures, the Latini et al. (2002, 1990) correlation for the dynamic viscosity of liquid refrigerants in saturated conditions was re-fitted and constants expressly dedicated to the studied low GWP refrigerants were obtained. Then, the proposed temperature-dependent correlation was modified to represent liquid dynamic viscosity dependence on pressure. In addition, an artificial neural network was developed to predict the dependence of the liquid viscosity of the studied refrigerants on temperature and pressure. This model was trained, validated, and tested for the selected dataset. The results of the proposed correlations and the multi-layer perceptron neural network were compared with the liquid viscosity calculations provided by some of the most well-known literature correlations and REFPROP 10.0, proving the accuracy of the proposed models for engineering applications.

Investigation of stiffness and damping coefficients in fluid film bearing with bio-oils and mineral-based oil

Rotating machinery utilizes fluid film bearings because of their good load carrying capacity and inherent damping properties. Fluid film bearings offer stiffness and damping parameters to ensure dynamic stability. The damping and stiffness characteristics of oil film significantly change the critical speed and unbalance response of the rotor. The damping and stiffness coefficients (direct, cross-coupled) may lead to system instability, also known as self-excited vibrations. Bio-oils have good tribological and physiochemical properties. They are also environment-friendly and bio-degradable. In this work, bio-oils (rapeseed, palm olein, and soybean) are evaluated in terms of their dynamic characteristics to that of mineral-based SAE40 lubricant for journal-bearing applications. The analytical extraction of damping and stiffness coefficients is performed based on the experimental dynamic viscosity data at different temperatures. In comparison to SAE40, the bio-oils have shown improved responsiveness. Bio-oils showed lower cross-coupled stiffness coefficients than SAE40, the primary source of rotor instability. The main contribution of this study is that it provides damping and stiffness coefficients for various bio-oils at different eccentricity ratios and viscosities for different types of oils. This may be used to characterize the dynamic properties of the fluid film bearing under various operating circumstances. It is concluded that the difference in cross-coupled stiffness favors bio-oils. Whereas, the difference in cross-coupled damping favors SAE40 by around 6%. This discrepancy is decreased to less than 2% for all oil’s final eccentricity ratio values (bio-oils and SAE40).

Simultaneous compressed liquid viscosity and density measurements of n-alkanes at temperatures between (291 and 353) K and pressures up to 50 MPa

Compressed liquid density (ρ) and dynamic viscosity (η) were simultaneously measured for pure liquid n-alkanes (n-hexane, n-heptane, n-octane, n-nonane, and n-decane) in the temperature range from (291 to 353) K and pressure up to 50 MPa by an experimental system using a coil capillary tube viscometer (CCTV) coupled with a vibrating tube densimeter (VTD). The reliability and validation of this measuring system were verified by determining and comparing both dynamic viscosity and density data of ethanol published in the international literature. The maximum viscosity deviation was 8 μPa ∙ s for viscosity and 0.87 kg ∙ m−3 for density. The measurements were carried out with a relative expanded uncertainty (k=2) of 1.00 % for the measurements of dynamic viscosity and 0.20 % for the measurements of density considering the impurities of the chemical compounds). Both dynamic viscosity and density data were represented using two empirical models, obtaining a maximum deviation of 2.49 % for the dynamic viscosity and 0.12 % for the density with the experimental data. Finally, the isothermal compressibility and isobaric thermal expansivity were calculated from the empirical models at the reported conditions.

Computational simulation of surface tension and gravitation-induced convective flow of a nanoliquid with cross-diffusion: An optimization procedure

The control of heat transfer in the hydromagnetic semiconductor crystal involves Marangoni convection with buoyancy forces. In this study, the conventional thermo-solutal Marangoni mixed flow model is modified by incorporating the solutal buoyancy effects that are significant in the flow phenomenon. The heat and mass transfer (HMT) characteristics of the Marangoni convective flow of a Cu − H2O nanofluid subjected to the assisting/resisting buoyancy forces and cross-diffusion are numerically studied. The homogeneous single-phase nanoliquid model is used in conjunction with experimental data of dynamic viscosity and thermal conductivity. The Dufour and Soret effects are considered. Governing equations are solved using the finite difference-based algorithm. The problem is analyzed in a unified way considering the cases of buoyancy-assisted flow and buoyancy-opposed flow. The response surface methodology (RSM) based on the face-centered composite design (CCD) is used to optimize the heat and mass transfer rates. A multivariate regression model is proposed and authenticated prior to optimization. Additionally, sensitivity analysis is performed using the full quadratic regression model. The increase in the temperature profile is more significant due to the radiative heat flux than the inclined magnetic field. Heat transfer has a high sensitivity to the appearance of thermal radiation, while mass transfer has a high sensitivity to the Soret effect. Simultaneous optimization of HMT rates is achieved with the high level of thermal radiation and low levels of the cross-diffusion aspects.

Entropy generation for MHD natural convection in enclosure with a micropolar fluid saturated porous medium with Al2O3Cu water hybrid nanofluid

This contribution gives a numerical investigation of buoyancy-driven flow of natural convection heat transfer and entropy generation of non-Newtonian hybrid nanofluid (Al2O3-Cu) within an enclosure square porous cavity. Hybrid nanofluids represent a novel type of enhanced active fluids. During the current theoretical investigation, an actual available empirical data for both thermal conductivity and dynamic viscosity of hybrid nanofluids are applied directly. Numerical simulation have been implemented for solid nanoparticles, the volumetric concentration of which varies from 0.0% (i.e., pure fluid) to 0.1% of hybrid nanofluids. Heat and sink sources are situated on a part of the left and right sides of the cavity with length B, while the upper and bottom horizontal sides are kept adiabatic. The stated partial differential equations describing the flow are mutated to a dimensionless formulas, then solved numerically via the help of an implicit finite difference approach. The acquired computations are given in terms of streamlines, isotherms, isomicrorotations, isoconcentraions, local Began number, total entropy, local and mean Nusselt numbers. The data illustrates that variations of ratio of the average Nusselt number to the averageNusselt of pure fluid Num+ is a decreasing function of Ha and φ, while e+ is an increasing function of Ha and φ parameters of hybrid nanofluid.

Density, dynamic viscosity, conductivity and refractive index for mixture D-glucose and deep eutectic solvent (choline chloride + urea) at different temperatures

ABSTRACT To convert carbohydrates into platform compounds, the deep eutectic solvent (DES) based on choline chloride and urea (molar ratio 1:2) was adopted as a green solvent. The physical properties of density, dynamic viscosity, conductivity and refractive index were determined for the mixture of D-glucose and DES including neat reline at a temperature from 293.15 K to 363.15 K at 101.3 kPa. The measured data of density, dynamic viscosity, conductivity and refractive index were correlated, respectively. Meanwhile, the molecular volume, standard molar entropy, lattice energy and free volume were calculated. The spectra of FTIR indicates that the hydrogen bond was changed in the mixture with increasing the content of D-glucose.