Showing papers on "Viscometer published in 2017"

Density, viscosity, and surface tension of five vegetable oils at elevated temperatures: Measurement and modeling

Abstract: Density, surface tension and viscosity of five food oils were experimentally measured using the Archimedean method, Pendant drop method, and Brookfield viscometer respectively. Measurements were pe...

Pressure dependence of viscosity in supercooled water and a unified approach for thermodynamic and dynamic anomalies of water

Abstract: The anomalous decrease of the viscosity of water with applied pressure has been known for over a century. It occurs concurrently with major structural changes: The second coordination shell around a molecule collapses onto the first shell. Viscosity is thus a macroscopic witness of the progressive breaking of the tetrahedral hydrogen bond network that makes water so peculiar. At low temperature, water at ambient pressure becomes more tetrahedral and the effect of pressure becomes stronger. However, surprisingly, no data are available for the viscosity of supercooled water under pressure, in which dramatic anomalies are expected based on interpolation between ambient pressure data for supercooled water and high pressure data for stable water. Here we report measurements with a time-of-flight viscometer down to 244 K and up to 300 MPa , revealing a reduction of viscosity by pressure by as much as 42%. Inspired by a previous attempt [Tanaka H (2000) J Chem Phys 112:799–809], we show that a remarkably simple extension of a two-state model [Holten V, Sengers JV, Anisimov MA (2014) J Phys Chem Ref Data 43:043101], initially developed to reproduce thermodynamic properties, is able to accurately describe dynamic properties (viscosity, self-diffusion coefficient, and rotational correlation time) as well. Our results support the idea that water is a mixture of a high density, “fragile” liquid, and a low density, “strong” liquid, the varying proportion of which explains the anomalies and fragile-to-strong crossover in water.

Shear and extensional rheology of commercial thickeners used for dysphagia management.

Abstract: People who suffer from swallowing disorders, commonly referred to as dysphagia, are often restricted to a texture-modified diet. In such a diet, the texture of the fluid is modified mainly by the addition of gum or starch-based thickeners. For optimal modification of the texture, tunable rheological parameters are shear viscosity, yield stress, and elasticity. In this work, the flow properties of commercial thickeners obtained from major commercial suppliers were measured both in shear and extensional flow using a laboratory viscometer and a newly developed tube viscometry technique, termed Pulsed Ultrasound Velocimetry plus Pressure Drop (PUV + PD). The two methods gave similar results, demonstrating that the PUV + PD technique can be applied to study flow during the swallowing process in geometry similar to that of the swallowing tract. The thickeners were characterized in relation to extensional viscosity using the Hyperbolic Contraction Flow method, with microscopy used as a complementary method for visualization of the fluid structure. The gum-based thickeners had significantly higher extensional viscosities than the starch-based thickeners. The rheological behavior was manifested in the microstructure as a hydrocolloid network with dimensions in the nanometer range for the gum-based thickeners. The starch-based thickeners displayed a granular structure in the micrometer range. In addition, the commercial thickeners were compared to model fluids (Boger, Newtonian, and Shear-thinning) set to equal shear viscosity at 50/s and it was demonstrated that their rheological behavior could be tuned between highly elastic, extension-thickening to Newtonian. Practical applications Thickeners available for dysphagia management were characterized for extensional viscosity to improve the understanding of these thickeners in large scale deformation. Extensional deformation behavior was further explained by using microcopy as corresponding technique for better understanding of structure/rheology relationship. Moreover, the major challenge in capturing human swallowing process is the short transit times of the bolus flow (<1 s). Therefore, the ultrasound-based rheometry method; PUV+PD which measures the real-time flow curve in ∼50 ms was used in addition to classical shear rheometry. The two methods complimented each other indicating that the PUV+PD method can be applied to study the transient swallowing process which is part of our future research, where we are studying the flow properties of fluids in an in vitro swallowing tract.

Viscosity Measurements Using Microfluidic Droplet Length

Abstract: Viscosity measurements have a wide range of applications from industrial chemical production to medical diagnosis. In this work, we have developed a simple droplet-based, water-in-oil continuous viscometer capable of measuring viscosity changes in 10 s or less and consuming a total sample volume of less than 1 μL/h. The viscometer employs a flow-focusing geometry and generates droplets under constant pressure. The length of the droplets (Ld) is highly correlated to the aqueous-phase viscosity (μaq) at high ratios of aqueous-inlet to oil-inlet pressure (AIP/OIP), yielding a linear relationship between μaq and 1/(Ld – Lc) where Lc is the minimal obtainable droplet length and approximately equals to the width of the droplet-generating channel. Theoretical analysis verifies this linear relationship, and the resulting equations can be used to optimize the design of the device such as the channel width, depth, and length. The viscometer can be used for Newtonian fluids and, by accurately calculating the shear r...

Test-Paper-Like Photonic Crystal Viscometer.

Abstract: A test-paper-like photonic crystal (PC) viscometer is fabricated based on the positive correlation between viscosity and the infiltration time for viscous liquid to entirely soak the PC film. It can be broadly used in different occasions to quickly determine the viscosity for many liquids, considering its portable and disposable characteristics and the requirement of little samples.

Micro-Viscometer for Measuring Shear-Varying Blood Viscosity over a Wide-Ranging Shear Rate

Abstract: In this study, a micro-viscometer is developed for measuring shear-varying blood viscosity over a wide-ranging shear rate. The micro-viscometer consists of 10 microfluidic channel arrays, each of which has a different micro-channel width. The proposed design enables the retrieval of 10 different shear rates from a single flow rate, thereby enabling the measurement of shear-varying blood viscosity with a fixed flow rate condition. For this purpose, an optimal design that guarantees accurate viscosity measurement is selected from a parametric study. The functionality of the micro-viscometer is verified by both numerical and experimental studies. The proposed micro-viscometer shows 6.8% (numerical) and 5.3% (experimental) in relative error when compared to the result from a standard rotational viscometer. Moreover, a reliability test is performed by repeated measurement (N = 7), and the result shows 2.69 ± 2.19% for the mean relative error. Accurate viscosity measurements are performed on blood samples with variations in the hematocrit (35%, 45%, and 55%), which significantly influences blood viscosity. Since the blood viscosity correlated with various physical parameters of the blood, the micro-viscometer is anticipated to be a significant advancement for realization of blood on a chip.

Effects of CaO/SiO2 Ratio and Na2O Content on Melting Properties and Viscosity of SiO2-CaO-Al2O3-B2O3-Na2O Mold Fluxes

Abstract: This paper investigated the effects of CaO/SiO2 ratio (0.8 to 1.5) and Na2O concentration (6 to 9 wt pct) on melting properties and viscosity of SiO2-CaO-Al2O3-B2O3-Na2O mold fluxes with a fixed B2O3 content. Melting properties of fluxes (softening temperature T s, hemispherical temperature T h, and fluidity temperature T f) were determined by the hot-stage microscopy method. Viscosity was measured using rotating cylindrical viscometer, and structure of quenched fluxes was studied using Raman spectroscopy. Equilibrium phases in the SiO2-CaO-Al2O3-B2O3-Na2O system were calculated using FactSage. It was found that T h decreased with increasing CaO/SiO2 ratio from 0.8 to 1.0 and increased with a further increase in the CaO/SiO2 ratio to 1.5. The effect of Na2O content in the range of 6 to 9 wt pct on T h of the flux with a fixed CaO/SiO2 ratio at 1.3 was marginal. Increasing CaO/SiO2 ratio and Na2O content increased the break temperature and reduced the value of viscosity at 1673 K (1400 °C). Viscosity of liquid fluxes was discussed in the relationship with the flux structure. Melting properties and viscosity of boracic fluxes were compared with those of industrial fluorine-containing mold fluxes.

Effect of Asphaltene on Phase Behavior and Thermophysical Properties of Solvent/Bitumen Systems

Abstract: Solvent-aided bitumen production from oil sands has shown promise as an alternative to thermal recovery methods. Phase behavior studies of solvent/bitumen mixtures are necessary for reservoir simulation of recovery methods, process design and operation of surface facilities, and transportation. Bitumen and heavy crudes comprise a different weight fraction of asphaltene. In this study, the effect of asphaltene on phase behavior, viscosity, and density of solvent/bitumen systems is studied. Ethane (C2H6) and carbon dioxide (CO2) are considered as solvents. Phase behavior studies and property measurements are conducted on solvent/bitumen and solvent/deasphalted bitumen systems. Solubility of C2H6 and CO2 in the original and deasphalted bitumen are measured. The viscosity and density of the liquid phase are also measured by inline viscometer and densitometer at temperature and pressure ranges of 70–130 °C and 2–8 MPa, respectively. The measured data showed that the asphaltene has no significant effect on C2H6...

Urea-Water-Solution Properties: Density, Viscosity, and Surface Tension in an Under-Saturated Solution

Abstract: A temperature-concentration dependent surface fit for the relative viscosity of a urea-water-solution (UWS) is calculated based on experimental and literature data. For the surface fit, a 2D Lorentzian function was used, where the x-axis was assigned to a urea mass fraction and the y-axis to the solution temperature and the rest of the Lorentzian function parameters were optimized based on the experimental and literature data. The surface model describes the relative viscosity of under-saturated urea-water-solution. The experimental data for the kinematic viscosity was measured with an Ubbelohde capillary viscometer whose temperature was controlled with a thermostat. The temperature and concentration range was from 293.15 to 353.15 K in 10-K increments and for urea mass fractions from 0.325 to 0.7. The kinematic viscosity values from the experiment were converted to relative viscosity by calculating the density of the UWS. An exponential fit was calculated to describe the specific gravity of the UWS based on literature data. Additionally, the surface tension of the UWS was measured at room temperature (293.15 K) in a mass fraction range from 0.302 to 0.596. As a result, simple models describing UWS properties were obtained and these models can be implemented into computational fluid dynamics (CFD) simulations.

Optimal design of structure in rheological models: an automotive application to dampers with high viscosity silicone fluids

Abstract: Dynamic torsional vibration dampers are for a long time inherent integral components of internal combustion engines. One of the most common types of the dynamic dampers is a silicone damper. It has been, for many years, perceived as an exclusively viscous damper, thus it has been constructed and designed according to this perception. When compared to other types of dynamic dampers of the similar size with flexible components used for their construction, the standard viscous damper has a lower damping effect. Moreover, this damper type has been a significantly cheaper and simpler solution. Current silicone oils with high nominal viscosity, having not only the expected damping properties, but also significant elastic characteristics under alternate shear stress, enable construction of dynamic dampers with a higher damping effect than a viscous damper. Frequency and temperature dependent complicated rheological properties of high viscosity silicone fluids can only be identified experimentally using a suitable dynamic viscometer. However, the measured frequency dependencies of both components of the complex shear modulus are only defined for harmonic loading while internal combustion engine load is periodic and contains several tens harmonics. The key to the solution is therefore to find suitable multiparameter rheological models comprised of linear elastic and damping elements that would approximate in the specified frequency range both components of the complex shear modulus. Such a complicated task can be solved using efficient optimization algorithms. This article focuses on the mathematical description of convolute rheological properties of high viscosity silicone liquids and also contains an example of the application of created rheological models in the complex dynamic model of a V10 diesel engine. A computational tool for the determination of stiffness and damping coefficients of the multi-parameter rheological model was created and solved in the optimization software GAMS by means of the CONOPT solver. The possibility of these modern technologies is shown by the comparison of computation models and experimentally set torsional vibration spectres with standard viscous damper and damper utilizing a high viscosity silicone oil.

A Rapid Capillary-Pressure Driven Micro-Channel to Demonstrate Newtonian Fluid Behavior of Zebrafish Blood at High Shear Rates

Abstract: Blood viscosity provides the rheological basis to elucidate shear stress underlying developmental cardiac mechanics and physiology. Zebrafish is a high throughput model for developmental biology, forward-genetics, and drug discovery. The micro-scale posed an experimental challenge to measure blood viscosity. To address this challenge, a microfluidic viscometer driven by surface tension was developed to reduce the sample volume required (3μL) for rapid ( 500 s−1), at which the power law exponent (n) of zebrafish blood was nearly 1 behaving as a Newtonian fluid. The measured values of whole blood from the micro-channel (4.17cP) and the vacuum method (4.22cP) at 500 s−1 were closely correlated at 27 °C. A calibration curve was established for viscosity as a function of hematocrits to predict a rise and fall in viscosity during embryonic development. Thus, our rapid capillary pressure-driven micro-channel revealed the Newtonian fluid behavior of zebrafish blood at high shear rates and the dynamic viscosity during development.

Effect of TiO 2 on the viscosity and structure of low-fluoride slag used for electroslag remelting of Ti-containing steels

Abstract: The viscosity of CaF2–CaO–Al2O3–MgO–(TiO2) slag was measured using a rotating crucible viscometer. Raman spectroscopy analysis was performed to correlate the viscosity to slag structure. The viscosity of the slag was found to decrease with increasing TiO2 content in the slag from 0 to 9.73wt%. The activation energy decreased from 95.16 kJ/mol to 79.40 kJ/mol with increasing TiO2 content in the slag. The introduction of TiO2 into the slag played a destructive role in Al–O–Al structural units and Q4 units by forming simpler structural units of Q2 and Ti2O6 4− chain. The amount of Al–O–Al significantly decreased with increasing TiO2 content. The relative fraction of Q4 units in the [AlO4]5−-tetrahedral units shows a decreasing trend, whereas the relative fraction of Q2 units and Ti2O6 4− chain increases with increasing TiO2 content accordingly. Consequently, the polymerization degree of the slag decreases with increasing TiO2 content. The variation in slag structure is consistent with the change in measured viscosity.

Densities and Viscosities for Binary Liquid Mixtures of Biodiesel + 1-Butanol, + Isobutyl Alcohol, or + 2-Butanol from 293.15 to 333.15 K at 0.1 MPa

Abstract: This paper presents experimental densities and viscosities of binary mixtures of biodiesel with 1-butanol, isobutyl alcohol, and 2-butanol from 293.15 to 333.15 K at 0.1 MPa. Densities are from a vibrating tube densimeter while viscosities are from a capillary glass viscometer. Experimental data of density and viscosity of pure alcohols agree with data reported in the literature with an average absolute percentage deviation of 0.06% and 1.3%, respectively. Experimental kinematic viscosities of the mixtures show a minimum value in the concentration range. The Grunberg–Nissan equation successfully correlates kinematic viscosities with an average absolute percentage deviation of 0.98%.

In Pursuit of a High-Temperature, High-Pressure, High-Viscosity Standard: The Case of Tris(2-ethylhexyl) Trimellitate

Abstract: This paper presents a reference correlation for the viscosity of tris(2-ethylhexyl) trimellitate designed to serve in industrial applications for the calibration of viscometers at elevated temperatures and pressures such as those encountered in the exploration of oil reservoirs and in lubrication. Tris(2-ethylhexyl) trimellitate has been examined with respect to the criteria necessary for an industrial standard reference material such as toxicity, thermal stability, and variability among manufactured lots. The viscosity correlation has been based upon all of the data collected in a multinational project and is supported by careful measurements and analysis of all the supporting thermophysical property data that are needed to apply the standard for calibration to a wide variety of viscometers. The standard reference viscosity data cover temperatures from 303 to 473 K, pressures from 0.1 to 200 MPa, and viscosities from approximately 1.6 to 755 mPa s. The uncertainty in the data provided is of the order of ...

Simultaneous Measurement of Dynamic Viscosity and Density of n-Alkanes at High Pressures

Abstract: New experimental data of the dynamic viscosity and density of pentane, octane, nonane, decane, and dodecane are reported. The experimental method was validated by determining and comparing the dynamic viscosity and the density of decane with the data previously published in the international literature, obtaining a maximum deviation of 12 μPa·s and 0.35 kg·m–3 for dynamic viscosity and density, respectively. The measurements were performed simultaneously using a capillary tube viscometer and a vibrating tube densimeter at temperatures between 293 and 353 K and pressures up to 30 MPa. The estimated relative combined expanded uncertainties (k = 2), considering the impurities of the compounds (including content of water), are 0.9% for the dynamic viscosity and 0.13% for the density over the entire measurement range. The viscosity data were successfully correlated as a function of pressure and temperature with an empirical model proposed in this study. Also, the experimental density data were successfully mod...

Effect of boron oxide addition on the viscosity-temperature behaviour and structure of phosphate-based glasses.

Abstract: In this study, nine phosphate-based glass formulations from the system P2 O5 -CaO-Na2 O-MgO-B2 O3 were prepared with P2 O5 content fixed as 40, 45 and 50 mol%, where Na2 O was replaced by 5 and 10 mol% B2 O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2 O3 addition on the viscosity-temperature behaviour, fragility index and structure of the glasses was investigated. The composition of the glasses was confirmed by ICP-AES. The viscosity-temperature behaviour of the glasses were measured using beam-bending and parallel -plate viscometers. The viscosity of the glasses investigated was found to shift to higher temperature with increasing B2 O3 content. The kinetic fragility parameter, m and F1/2 , estimated from the viscosity curve were found to decease with increasing B2 O3 content. The structural analysis was achieved by a combination of Fourier transform infrared spectroscopy and solid state nuclear magnetic resonance. 31 P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing B2 O3 content. As B2 O3 was added to the glass systems, the phosphate connectivity increases as the as the Q1 units transforms into Q2 units. The 11 B NMR results confirmed the presence of tetrahedral boron (BO4 ) units for all the compositions investigated. Structural analysis indicates an increasing level of cross-linking with increasing B2 O3 content. Evidence of the presence of P-O-B bonds was also observed from the FTIR and 31 P NMR analysis. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 764-777, 2017.

An automated system for performing continuous viscosity versus temperature measurements of fluids using an Ostwald viscometer.

Abstract: An automated system was developed to measure the viscosity of fluids as a function of temperature using image analysis tracking software. An Ostwald viscometer was placed in a three-wall dewar in which ethylene glycol was circulated using a thermal bath. The system collected continuous measurements during both heating and cooling cycles exhibiting no hysteresis. The use of video tracking analysis software greatly reduced the measurement errors associated with measuring the time required for the meniscus to pass through the markings on the viscometer. The stability of the system was assessed by performing 38 consecutive measurements of water at 42.50 ± 0.05 °C giving an average flow time of 87.7 ± 0.3 s. A device was also implemented to repeatedly deliver a constant volume of liquid of 11.00 ± 0.03 ml leading to an average error in the viscosity of 0.04%. As an application, the system was used to measure the viscosity of two Li-ion battery electrolyte solvents from approximately 10 to 40 °C with results showing excellent agreement with viscosity values calculated using Gering's Advanced Electrolyte Model (AEM).

A contact resonance viscometer based on the electromechanical impedance of a piezoelectric cantilever

Abstract: In this work, we proposed a self-sensing contact resonance viscometer based on the electromechanical impedance of a piezoelectric bimorph cantilever whose free end is perpendicularly attached by a sensing slice. During measurement, the sensing slice is immersed into the fluid and excited in-plane vibration by the piezoelectric cantilever. The mechanical impedance from the fluid load is analyzed and the electromechanical impedance of the cantilever-fluid system is derived by using an equivalent circuit model. Then we track the electric impedance of piezoelectric bimorph to extract the dynamic viscosity of the testing fluid, based on the shift of the resonance frequency and the quality factor. Calibration experiments were carried out using glycerol-water solutions with different concentrations (10–2000 cP). Finally, the viscosities of olive oil and silicon oil were measured using the calibrated curves, and the results coincided with that given by the standard viscometer. The proposed method is very promising for online viscosity measurement, especially for high-viscosity fluid, due to its high quality factor and self-sensing characteristic.

Viscosity Measurement of Slags using Rotating Bob and Vibrating Finger Viscometer

Abstract: Viscosity is one of the most important properties of the metallurgical melts (slag and steel) and an accurate information about this property is crucial for a better understanding, stabilization and modeling of the metallurgical processes.5) In addition, viscosity is also essential for the infiltration and gas atomization processes.6,7) Nowadays the most common method for the determination of viscosity at high temperature is the concentric cylinder method. Upon recent ten years, this method has been widely used for the determination of the slag viscosity.8–16) However, it is difficult to determine a precise low torque due to the mechanical friction inside the viscometer.17) Viscometers of this type consist of two concentric cylinders (a bob and a crucible) and the viscosity is determined from the calculations of the torque of bob at constant or different rotations. A few other studies were reported to use the different types of viscometers such as the rotation crucible viscometer and the oscillating plate method.17–20) The concentric cylinder method was primary used for the determination of slag viscosity. It Viscosity Measurement of Slags using Rotating Bob and Vibrating Finger Viscometer