Experimental Viscosity Data Research Articles

Viscosity and fragility of selected glass-forming chalcogenides

Experimental viscosity data for (GeSe2)x(Sb2Se3)100-x melts (x = 50, 60 and 70), obtained by deploying the pressure-assisted melt filling technique (PAMFT), are presented. These data were combined with previously published literature data and fitted over a broad temperature range including glass, undercooled melt, and melt regions by the Mauro–Yue–Ellison–Gupta–Allan (MYEGA) equation. A detailed analysis of different fragility concepts for the studied glass-forming system as well as for other well-known chalcogenide glass formers is presented. On the basis of this extensive analysis, a simple procedure for carrying out viscosity data extrapolation was developed, and the validity of this procedure is discussed.

A novel theoretical strategy for modeling viscosity of polymer melts: Modified friction theory with PC-SAFT

Despite its importance, the role of pressure in the viscosity of polymer melts is little known. A modified friction theory (f-theory) combined with perturbed-chain statistical association fluid theory (PC-SAFT) was proposed to model the dynamic viscosity of polymer melts under high pressure and shear rate. Viscosity data points were collected from literature and analyzed. Different estimation strategies for PC-SAFT parameters for polymers were assessed from the perspective of molecular weight. The resulted appropriate parameters were used to calculate the attractive and repulsive pressures of the polymers, and the pressures were then used as inputs of both linear friction model and modified f-theory for viscosity modeling. The parameters of two models were obtained by fitting to the experimental viscosity data. The overall average absolute relative deviation (AARD) of the modified f-theory for viscosity modeling is 4.42%, which indicates the good modeling performance of the modified f-theory.

Development of viscosity model for aluminum alloys using BP neural network

Viscosity is one of the important thermophysical properties of liquid aluminum alloys, which influences the characteristics of mold filling and solidification and thus the quality of castings. In this study, 315 sets of experimental viscosity data collected from the literatures were used to develop the viscosity prediction model. Back-propagation (BP) neural network method was adopted, with the melt temperature and mass contents of Al, Si, Fe, Cu, Mn, Mg and Zn solutes as the model input, and the viscosity value as the model output. To improve the model accuracy, the influence of different training algorithms and the number of hidden neurons was studied. The initial weight and bias values were also optimized using genetic algorithm, which considerably improve the model accuracy. The average relative error between the predicted and experimental data is less than 5%, confirming that the optimal model has high prediction accuracy and reliability. The predictions by our model for temperature- and solute content-dependent viscosity of pure Al and binary Al alloys are in very good agreement with the experimental results in the literature, indicating that the developed model has a good prediction accuracy.

An Experimental Study of Steam-Solvent Coinjection for Bitumen Recovery Using a Large-Scale Physical Model

Summary In this paper, we present a solvent-assisted steam-assisted gravity drainage (SA-SAGD) experiment with multicomponent solvent (i.e., condensate) using a large physical model. The sandpack for the experiment had a porosity of 0.33 and a permeability of 5.6 darcies in the cylindrical pressure vessel that was 1.22 m in length and 0.425 m in internal diameter. The sandpack was initially saturated with 93% Athabasca bitumen and 7% deionized water. The main objective of this research was to study the in-situ thermal/compositional flow and produced bitumen properties in SA-SAGD with condensate. After the preheating of the sandpack for 24 hours, SA-SAGD with 2.8-mol% condensate was performed at 50 cm3/min (cold-water equivalent) at 3500 kPa for 3 days. The experimental data of production, injection, and temperature distribution were recorded. Also, 10 samples of produced oil were taken and analyzed for density and asphaltene content. The sandpack was excavated after the experiment to analyze the asphaltene content in the remaining oil at different locations. A numerical simulation model was calibrated based on the data of material balance and temperature distribution, and it was validated with properties of the produced and excavated samples. The simulation model used fluid models based on experimental data of viscosities, densities, and bubblepoints for four condensate/bitumen mixtures. Results showed that SA-SAGD was efficient in bitumen recovery with a cumulative steam-to-oil ratio (SOR) that was two to three times smaller than that in SAGD using the same physical model. Detailed analysis of the calibrated simulation model indicated that SA-SAGD enabled the steam chamber to expand more efficiently with a smaller amount of water throughput than SAGD. Volatile solvent components tended to remain in the chamber, and the condensed solvent components acted as a miscible carrier for bitumen components. The analysis further showed that the more efficient oil recovery in SA-SAGD occurred with predominantly cocurrent flow of oil and water near the chamber edge. SA-SAGD recovered a larger amount of asphaltene components (i.e., less in-situ upgrading) than SAGD likely because of its lower chamber temperature, shorter production period, and enhanced local displacement efficiency.

Reinvestigating the Parabolic-Shaped Eddy Viscosity Profile for Free Surface Flows

The flow in rivers is turbulent. The main parameter related to turbulence in rivers is the eddy viscosity, which is used to model a turbulent flow and is involved in the determination of both velocities and sediment concentrations. A well-known and largely used vertical distribution of eddy viscosity in free surface flows (open channels and rivers) is given by the parabolic profile that is based on the logarithmic velocity profile assumption and is valid therefore only in the log-law layer. It was improved thanks to the log-wake law velocity profile. These two eddy viscosities are obtained from velocity profiles, and the main shortcoming of the log-wake profile is the empirical Coles’ parameter. A more rigorous and reliable analytical eddy viscosity model is needed. In this study, we present two analytical eddy viscosity models based on the concepts of velocity and length scales, which are related to the exponentially decreasing turbulent kinetic energy (TKE) function and mixing length, namely, (1) the exponential-type profile of eddy viscosity and (2) an eddy viscosity based on an extension of von Karman’s similarity hypothesis. The eddy viscosity from the second model is Re*-independent, while the eddy viscosity from the first model is Re*-dependent (where Re* is the friction Reynolds number). The proposed analytical models were validated through computation of velocity profiles, obtained from the resolution of the momentum equation and comparisons to experimental data. With an additional correction function related to the damping effect of turbulence near the free surface, both models are similar to the log-wake-modified eddy viscosity profile but with different values of the Coles’ parameter, i.e., Π=0.2 for the first model and Π=0.15 for the second model. These values are similar to those found in open-channel flow experiments. This provides an explanation about the accuracy of these two analytical models in the outer part of free surface flows. For large values of Re* (Re* > 2000), the first model becomes Re* independent, and the two coefficients reach asymptotic values. Finally, the two proposed eddy viscosity models are validated by experimental data of eddy viscosity.

Recommended Values of the Viscosity in the Limit of Zero Density for R134a and Six Vapors of Aromatic Hydrocarbons as Well as of the Initial Density Dependence of Viscosity for R134a. Revisited from Experiment Between 297\xa0K and 631\xa0K

Previously published experimental viscosity data at low density, originally obtained using all-quartz oscillating-disk viscometers for R134a and six vapors of aromatic hydrocarbons in the temperature range between 297 K and 631 K at most, were re-evaluated after an improved re-calibration. The relative combined expanded (k=2) uncertainty of the re-evaluated data are 0.2 % near room temperature and increases to 0.3 % at higher temperatures. The re-evaluated data for R134a as well as for the vapors of mesitylene, durene, diphenyl, fluorobenzene, chlorobenzene, and p-dichlorobenzene were arranged in approximately isothermal groups and converted into quasi-isothermal viscosity data using a first-order Taylor series in temperature. Then, the data for R134a were evaluated by means of a series expansion truncated at first order to obtain the zero density and initial density viscosity coefficients, eta ^{(0)} and eta ^{(1)}. For the six aromatic vapors, the Rainwater–Friend theory for the initial density dependence of the viscosity was used to derive eta ^{(0)} values. Finally, reliable eta ^{(0)} and also eta ^{(1)} values for R134a were selected as reference values in the measured temperature range to be applied when generating a new viscosity formulation.

A novel view on classification of glass-forming liquids and empirical viscosity model

In the last few decades, theoretical and experimental studies of glass-forming liquids have revealed presence of universal regularities in the viscosity-temperature data. In the present work, we propose a viscosity model for scaling description of experimental viscosity data. A feature of this model is presence of only two adjustable parameters and high accuracy of experimental data approximation by this model for a wide temperature range. The basis of the scaling description is an original temperature scale. Within this scaling description we obtain the transformed Angell plot, in which the area separating “fragile” and “strong” glass-formers emerges. The proposed scaling procedure make it possible to reconsider belonging some liquids to the type of “fragile” glass-formers. The obtained results form basis for development of a generalized scaling description of crystallization kinetics in supercooled liquids and glasses.

Helmholtz Scaling: An Alternative Approach to Calculate Viscosity with the PCP-SAFT Equation of State

We propose an alternative approach to calculate viscosity, based on the Rosenfeld scaling theory, which can be applied to pure components and their mixtures in a wide range of temperatures, pressures, and compositions. The Helmholtz scaling (A-scaling) applies the Chapman–Enskog relation, an Ansatz function, and the PCP-SAFT equation of state to predict the viscosity. Although it was implemented with the PCP-SAFT EoS, A-scaling has potential to be coupled with other EoS. Substances from n-alkanes, alcohols, aromatics, ethers, chlorofluorocarbons, carbon dioxide, and nitrogen were used to obtain five parameters to better correlate the experimental viscosity data. We tested the A-scaling performance of predicting the viscosity of 33 binary mixtures at different temperature and pressure conditions. For pure components, the minimum and maximum average absolute deviations (AADs) were 1.51 and 6.53%, respectively. Meanwhile, for mixtures, 0.70 and 23.95% were the lowest and highest values. By comparing this method with the successful and consolidated entropy scaling, it was found that AADs in most of the pure substances and mixtures were lower for A-scaling. Thus, since it is suitable for polar, nonpolar, and hydrogen-bonding substances, A-scaling covers many substances for industry applications, with no usage of adjustable parameters to predict viscosity for mixtures.

Experimental investigation of the effect of Al2O3 nanoparticles with spherical and rod-shaped morphologies on the thermophysical properties of ionic nanofluids

Ionic Liquid(IL)now refers to fluids that are liquid at temperatures above 100°C, they are called Greensolvents.One of their applications is in heat transfer and solar collectors.Thermophysical properties can be improved by adding nanoparticles to the IL.For this reason,spherical and rod-shaped alumina nanoparticles were added to 1-Hexyl-3-methyl imidazolium hexafluorophosphate IL with different weight percentages. The effect of adding nanoparticles on thermophysical properties of IL such as density,viscosity,thermal conductivity, and heat capacity in 0.05,0.1 and 0.5 %wt of nanoparticles at temperatures of 20, 30, and 50 °C is investigated. Increasing the concentration of nanoparticle set out an increase in density, viscosity, and thermal conductivity and a decrease in the thermal capacity of the ionic nanofluid (INF) compared to the base IL.Also, the viscosity, density, and thermal conductivity in INF with rod-shaped alumina nanoparticles are improved more than spherical alumina nanoparticles. Also the experimental viscosity and thermal conductivity data were fitted with the existing theoretical models. the viscosity of spherical alumina-IL and rod-shape alumina-IL was in unison with particles aggregation effect (Krieger-Dougherty model) and the both INF effective thermal conductivity are prognosticated by interfacial layer approach with sufficient accuracy.Eventually nonlinear equations have also been proposed for changes in the thermophysical properties of viscosity.

Optical and viscometric properties for 1-chlorohexane + toluene/tetradecane binary mixtures at temperatures from 298.15 K to 318.15 K and atmospheric pressure

The optical and viscometric properties for two binary mixtures of 1-chorohexane with toluene and tetradecane, were measured at several temperatures in the range of (298.15–318.15) K and atmospheric pressure.The experimental values for refractive indices and viscosities, for both systems were correlated by the Jouyban-Acree model with good accuracy.By using the obtained experimental results, the related excess and deviation quantities, as the deviation in refractive indices, the molar refractions, the deviation in molar refraction and the deviation in viscosities, were calculated and reported in this work. All these excess properties were correlated with the Redlich-Kister polynomial equation.The Lorentz–Lorenz, Gladstone–Dale, Arago–Biot, Edwards, and Eykman predictive equations have been used to calculate the refractive index on basis of measured density, and their accuracy was analyzed.Some different equations: Grunberg–Nissan, Katti Chaudry, Hind, Dolezalek, and three-body McAllister interaction model, were used to calculate the viscosities values and a comparison with those values with the experimental data was made. From the viscosity experimental data, the molar enthalpy of activation and the molar entropy of activation for viscous flow, as well as the excess Gibbs energy of activation for viscous flow, were calculated for both studied binary mixtures.Discussions concerning the experimental and calculated results in relation to the molecular interactions and structural effects between components of mixtures are presented.

РЕОЛОГИЧЕСКОЕ ПОВЕДЕНИЕ ПОРОШОК-ПОЛИМЕРНЫХ СМЕСЕЙ И МОДЕЛЬНОЕ ОПИСАНИЕ ВЯЗКОСТИ ФИДСТОКА ДЛЯ ЧИСЛЕННОГО МОДЕЛИРОВАНИЯ ПРОЦЕССА ИНЖЕКЦИОННОГО ФОРМОВАНИЯ

The rheological behavior of the powder-polymer composition prepared for the application in the powder injection molding (PIM) technology has been studied. A review of models used to describe the rheological behavior of powder slips is presented. A viscosity study of MIM-4140 feedstock with a wax-polyolefin binder was carried out on a capillary rheometer with different capillary diameters. Empirical coefficients of viscosity models were determined. Verification of calculated viscosity values and experimental data for the studied feedstock is presented.

Thermodynamic, transport, and structural properties of hydrophobic deep eutectic solvents composed of tetraalkylammonium chloride and decanoic acid.

With the emergence of hydrophobic deep eutectic solvents (DESs), the scope of applications of DESs has been expanded to include situations in which miscibility with water is undesirable. Whereas most studies have focused on the applications of hydrophobic DESs from a practical standpoint, few theoretical works exist that investigate the structural and thermodynamic properties at the nanoscale. In this study, Molecular Dynamics (MD) simulations have been performed to model DESs composed of tetraalkylammonium chloride hydrogen bond acceptor and decanoic acid hydrogen bond donor (HBD) at a molar ratio of 1:2, with three different cation chain lengths (4, 7, and 8). After fine-tuning force field parameters, densities, viscosities, self-diffusivities, and ionic conductivities of the DESs were computed over a wide temperature range. The liquid structure was examined using radial distribution functions (RDFs) and hydrogen bond analysis. The MD simulations reproduced the experimental density and viscosity data from the literature reasonably well and were used to predict diffusivities and ionic conductivities, for which experimental data are scarce or unavailable. It was found that although an increase in the cation chain length considerably affected the density and transport properties of the DESs (i.e., yielding smaller densities and slower dynamics), no significant influence was observed on the RDFs and the hydrogen bonds. The self-diffusivities showed the following order for the mobility of the various components: HBD > anion > cation. Strong hydrogen bonds between the hydroxyl and carbonyl groups of decanoic acid and between the hydroxyl group of decanoic acid and chloride were observed to dominate the intermolecular interactions.

The study of interactions in aqueous solutions of 1-alkyl-3-(3-butenyl)imidazolium bromide ionic liquids

In the present study, volumetric and viscosimetric properties of aqueous solutions of imidazolium-based ionic liquids (ILs) with unsaturated and variety of different alkyl chain lengths, 1-alkyl-3-(3-butenyl)imidazolium bromide (([RC3=Cim][Br]), R = methyl (C1), ethyl (C2) or butyl (C4)) were investigated. The experimental density and viscosity are measured as a function of the IL concentration at T = (293.15 to 313.15) K and atmospheric pressure (p = 101325 Pa). The volumetric property analysis is done to adjudge the effect of the introduced double bond, length of the alkyl chain on the imidazolium ring and hydrophilic non-hydrolyzable anion environment on the overall volumetric changes at infinite dilution. The experimental viscosity data are analyzed using the Jones-Dole equation to evaluate the viscosity B-coefficients. The results are discussed in terms of the interactions occurring in solution and compared with that available in the literature for corresponding saturated analogues.

Density and Viscosity of Aqueous (Ammonia + Carbon Dioxide) Solutions at Atmospheric Pressure and Temperatures between 278.15 and 318.15 K

The density and the viscosity of aqueous (NH3 + CO2) solutions have been measured at atmospheric pressure over a temperature range of 278 to 318 K and apparent concentrations of solute between 4 and 10 molNH3 kgH2O–1 for NH3 and between 1 and 5.2 molCO2 kgH2O–1 for CO2. Solute loss from the aqueous solution associated with the high equilibrium partial pressure of NH3 and of CO2 has been limited by devices and protocols developed ad-hoc for sample preparation and density and viscosity measurement. Solid or vapor formation out of the initial liquid mixture has been avoided by means of a thermodynamic model-driven design of experiments. The experimental values gathered in this work have been used to obtain empirical models of density and viscosity, as a function of the apparent concentration of solutes, that is, NH3 and CO2, and temperature, that are able to reproduce the experimental values in all cases with deviations below 1.1% for density and below 9.4% for viscosity. While it is the first time that, to our knowledge, experimental viscosity data of aqueous ammonia solutions loaded with CO2 are added to the literature, the density model developed in this work is also able to reproduce experimental density data from literature with deviations below 1.5%, even outside the boundaries of the experimental conditions considered in this work.

Viscosity, density, and derived thermodynamic properties of aqueous 2-(ethylamino)ethanol (EAE), aqueous aminoethylethanolamine (AEEA), and its mixture for post-combustion CO2 capture

In the present study, viscosity and density of aqueous 2-(ethylamino)ethanol (EAE), aqueous aminoethylethanolamine (AEEA), and aqueous EAE + AEEA blend were measured in the temperature range of 293.15 K to 333.15 K at atmospheric pressure. Concentration of aqueous amines was used upto 30 wt% that is usually applicable for CO2 absorption from flue gases in post combustion CO2 capture process. EAE/AEEA weight ratio was 9/1, 8/2, and 7/3 in the aqueous EAE + AEEA blend. Viscosity of all mixtures increased by increasing amine concentration and decreased by increasing temperature of samples. Experimental viscosity data were correlated to newly proposed models and average absolute deviation (AAD) % was 1.515, 2.027, and 2.889 for viscosity of EAE + H2O, AEEA + H2O, and EAE + AEEA + H2O, respectively. Density of aqueous EAE and aqueous EAE + AEEA blend (at fixed EAE/AEEA weight ratio) decreased by increasing amount of amine in the mixture but aqueous AEEA showed increased density by increasing concentration of AEEA. Excess molar volume (VE) calculated for all aqueous mixtures and VE of aqueous EAE and aqueous AEEA was fitted in Redlich-Kister equation. Density of aqueous EAE + AEEA blend was correlated to a new empirical model and AAD % for this model was 0.018. Isobaric thermal expansion coefficient (αp) of binary and ternary solutions was calculated from density versus temperature data. Activation molar enthalpy (∆H∗), activation molar entropy (∆S∗), and activation molar Gibbs free energy (∆G∗) at 298.15 K for aqueous EAE, aqueous AEEA, and aqueous EAE + AEEA blend were calculated using viscosity and density data on the basis of Eyring theory of liquid viscosity.

Simulation approaches for the mechanisms of thermoset polymerization reactions

Abstract Detailed modeling and simulation of the reaction of alcohol and isocyanate moieties to form urethane have provided a reason to question conventional opinions that this is a step-growth polymerization process. In particular, industrial formulations are dominated by catalytic mechanisms, and these chain mechanisms can change the polymer growth mechanism. This paper's research evaluates experimental data of reaction temperature and resin viscosity of urethane gel reactions that substantiate a chain-growth mechanism. One of the artifacts of a chain-growth mechanism is the rapid appearance of relatively large molecules that reduce gel point times earlier with step-growth mechanisms.

Density, Viscosity, and Derivative Properties of Diethylene Glycol Monoethyl Ether Under High Pressure and Temperature

The measurement of densities (ρ) of the pure component diethylene glycol monoethyl ether (2-(2-ethoxyethoxy)ethanol) has been carried out using a vibrating-tube densimeter (Anton Paar DMA HPM) along temperatures varying from 293.15 to 353.15 K and pressures from 0.1 to 70 MPa with an expanded uncertainty of 0.5 kg·m–3. High-pressure dynamic viscosity (η) measurements were performed with a falling body viscometer at pressure values up to 70 MPa and within a temperature range from 293.15 to 353.15 K with an expanded relative uncertainty of 0.03η. The dynamic viscosity was determined at 0.1 MPa, thanks to an Ubbelohde capillary viscometer, with an expanded relative uncertainty smaller than 0.01η. Density experiments were adjusted using a Tait-like equation and modeled by employing the perturbed-chain statistical associating fluid equation of state (EoS). Moreover, high-pressure dynamic viscosity experimental data were correlated using the Vogel–Fulcher–Tammann (VFT) equation.

Fractional Walden rule for aprotic ionic liquids: Experimental verification over a wide range of temperatures and pressures

The Walden rule, revealing a universal conductivity-viscosity relationship, is considered as a useful tool to investigate the transport mechanism in ionic liquids (ILs). In this work, we constructed the Walden plots covering 10 orders of magnitude for two ILs: 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [BMMIm][NTf2] and 1-butyl-3-methylimidazolium bis(perfluoroethylsulfonyl)imide [BMIm][BETI] using experimental viscosity data at pressures up to 950 MPa supplemented by high-pressure conductivity and density data. Moreover, the high-pressure viscosity data of studied ILs revealed an inflection point denoting a transition from slower to faster than exponential dependence of viscosity on pressure. Finally, we found that the experimental viscosity data conform to the thermodynamic density scaling idea for each IL, with the scaling parameter equal to the ratio of scaling exponent obtained for conductivity data to the slope of the Walden plot. Consequently, our results show a promising method to generate high-pressure viscosity data especially for highly viscous aprotic ionic liquids, which are technically impossible to measure.

Experimental Study on the Viscosity of 1-(2-HE)PP Aqueous Solutions

In this paper, we measured the viscosities (η) data of aqueous solutions of 1-(2-Hydroxyethyl)-piperidine (1-(2-HE)PP) by using NDJ-5S digital rotary viscometer. The mass fractions of 1-(2-HE)PP ranged from 0.1 to 1, and the experimental temperatures were 303.2 K, 313.2 K and 323.2 K respectively. The effects of temperature and W1_(2-HE)pp on viscosity were demonstrated. Based on the experimental data of viscosity, we deduced the activation energy (Ea) and CO2 diffusion coefficient (Dco2) of 1-(2-HE)PP aqueous solutions.

Rheological, EMI and corrosion properties of epoxy coating with nanoparticle and conductive carbon black

The purpose of this paper was determining the effects of two nanoparticles additions in a commercial epoxy coating system on rheology characterization. Two kinds of hybrid organic–inorganic silicates (benzytallowdimethylammonium salts with bentonite) were studied, APA, with C14-16 organic chain and, HT, with C2-4 organic chain. A 22 factorial design, with two categorical nanoparticules factors was applied. The experimental data of viscosity were fit to three different rheological constitutive models: Herschell-Bulkley, Carreau-Yasuda and Cross. The best fit was obtained by Herschel-Bulkley model. The APA nanoparticle had substantial changes in yield stress values, but no effect was observed when HT had been isolated. Two thixotropic models were analyzed for the epoxy system, and the better performance was observed for the model with two rheological parameters. The presence of nanoparticule in epoxy coating reduced around 40% the recovery time. The addition of nanoparticules changes the rheological properties of a commercial coating. The X-Rays Diffraction analyses were done to observe the dispersions degree and exfoliations in the epoxy system. The crystalline peak of nanoparticles had lost for all coating formulations. The electromagnetic interference shielding attenuation was 60% in the formulations with high content of both nanoparticles. The APA and HT improved hence, the anticorrosion performance of the epoxy coating for 720 h in chloride solution. Corrosion resistance had the best performance in the coating with high concentration of carbon black and nanoparticles.