Viscosity-temperature correlation for glycerol-water solutions

Chen, Yen-Ming; Pearlstein, Arne J.

doi:10.1021/ie00068a030

Cited by 57 publications

(41 citation statements)

References 12 publications

(17 reference statements)

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“…Literature values for the temperature dependence of solvent viscosity (decalin [31], glycerol [32], 1:1 water:glycerol [32], 3-methylpentane [33], and 1-propanol [34]) were used to calculate the tumbling correlation time, τ, based on the StokesEinstein equation (τ= c slip V η/kT, V = molecular volume, k = Boltzmann's constant). The slip coefficient, c slip , was adjusted to fit the experimental data.…”

Section: Nitroxyl Tumbling Correlation Timesmentioning

confidence: 99%

Electron spin–lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids

Sato

Bottle

Blinco

et al. 2008

Journal of Magnetic Resonance

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Electron spin-lattice relaxation rates, 1/T 1 , at X-band of nitroxyl radicals (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidin-1-oxyl and 3-carbamoyl-2,2,5,5-tetramethylpyrrolin-1-oxyl) in glass-forming solvents (decalin, glycerol, 3-methylpentane, o-terphenyl, 1-propanol, sorbitol, sucrose octaacetate, and 1:1 water:glycerol) at temperatures between 100 K and 300 K were measured by long-pulse saturation recovery to investigate the relaxation processes in slow-to-fast tumbling regimes. A subset of samples was also studied at lower temperatures or at Q-band. Tumbling correlation times were calculated from continuous wave lineshapes. Temperature dependence and isotope substitution ( 2 H and 15 N) were used to distinguish the contributions of various processes. Below about 100 K relaxation is dominated by the Raman process. At higher temperatures, but below the glass transition temperature, a local mode process makes significant contributions. Above the glass transition temperature, increased rates of molecular tumbling modulate nuclear hyperfine and g anisotropy. The contribution from spin rotation is very small. Relaxation rates at X-band and Q-band are similar. The dependence of 1/T 1 on tumbling correlation times fits better with the Cole-Davidson spectral density function than with the Bloembergen-Purcell-Pound model.

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Section: Nitroxyl Tumbling Correlation Timesmentioning

confidence: 99%

Electron spin–lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids

Sato

Bottle

Blinco

et al. 2008

Journal of Magnetic Resonance

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“…All experiments were run at ambient temperature (24±3 • C) with aqueous solutions of glycerol (anhydrous, purity 99%, MERCK) at glycerol concentrations of 40 or 60% m/m, respectively, with kinematic viscosities of 25 • C = 2.85 × 10 −6 m 2 /s (40% m/m) and 25 • C = 7.55 × 10 −6 m 2 /s (60% m/m)--- Chen and Pearlstein, 1987. The unit used for the experiments is depicted in Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

Effect of the rotor shape on the mixing characteristics of a continuous flow Taylor-vortex reactor

Richter

Hoffmann

Kraushaar‐Czarnetzki

2008

Chemical Engineering Science

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Macro-and micromixing in a continuous flow Taylor-vortex reactor with novel ribbed rotors were investigated and compared to the features of a classical cylindrical rotor. The characterisation was performed in a wide hydrodynamic range (40 < Ta < 2500 and 0.03 < Re < 0.51) through tracer experiments and the analysis of the rotor power consumption. Additionally, the flow patterns were visualised by using a rheoscopic fluid. The results show that the novel rotors equipped with ribs immobilise and stabilise the vortices. As compared to cylindrical rotors, micromixing is clearly enhanced while axial dispersion can be simultaneously reduced. Through the use of ribbed rotors, the operational window can be broadened considerably, in which the reactor runs at very low or moderate extent of macromixing.

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“…No nosso caso, a temperatura da glicerina variou de 23,0 a 24,0 • C durante a realização do experimento, enquanto SCS reportam um intervalo de 23,5 a 24,2 • C. Para se ter a referência de viscosidade como função da temperatura baseada na literatura, usamos a relação entre a viscosidade e a temperatura absoluta proposta por Chen e Pearlstein [22],…”

Section: Análise Dos Resultadosunclassified

Determinação da viscosidade por meio da velocidade terminal: uso da força de arrasto com termo quadrático na velocidade

Vertchenko

2017

Rev. Bras. Ensino Fís.

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Propomos a correção, por um fator adimensional, do termo quadrático na velocidade da força de arrasto de Oseen para que ela seja usada na determinação do coeficiente de viscosidade da glicerina através da medição da velocidade terminal de esferas em queda dentro do fluido. Esse fator incorpora o efeito da parede do recipiente sobre o movimento das esferas, analogamenteà correção da força de Stokes pelo fator de Ladenburg, e permite compatibilizar a força de Oseen com os dados experimentais do coeficiente de arrasto até números de Reynolds próximos a 30. Admitindo uma relação de proporcionalidade entre esses fatores, o coeficiente de viscosidade passa a ser o coeficiente linear na relação entre a viscosidade que seria obtida se fosse considerada apenas a força de Stokes e o produto da velocidade terminal pelo diâmetro das esferas. A experiência com esferas de aço em queda dentro de tubos de diferentes diâmetros forneceu valores para o coeficiente de viscosidade compatíveis com a temperatura em que se trabalhou. Esse método pôde ser aplicado até números de Reynolds da ordem da dezena, relaxando a restrição de se trabalhar com números de Reynolds inferiores a 0,5 na determinação da viscosidade através do método de Stokes. Palavras-chave: Força de arrasto, viscosidade, número de Reynolds.A correction to the term with quadratic dependency of the velocity in the Oseen s drag force by a dimensionless factor is proposed in order to determine the viscosity of glycerin through the measurement of the terminal velocity of spheres falling inside the fluid. This factor incorporates the effect of the container s wall over the movement of the spheres, analogously to the correction of the Stoke s force by the Landenburg factor, and permits to make the Oseen s force compatible with the experimental data for the drag coefficient up to Reynolds number near 30. Admitting a proportionality relation between these factors, the viscosity coefficient turns into a linear coefficient in the relation between the parameter that corresponds to the viscosity that would be determined if only the Stokes' force was considered and the product of the terminal velocity by the diameter of the spheres. The experiment with steel spheres falling inside tubes of different diameters showed values for the viscosity coefficient of glycerin compatible with the expected, for the temperature range worked. This method might be applied to Reynolds number of order of ten of the sphere's motion, relaxing the restriction of working with Reynolds numbers inferior to 0.5 for the determination of the viscosity through the Stokes' method. Keywords: Drag force, viscosity, Reynolds number. IntroduçãoA viscosidade está associada a uma espécie de atrito interno que causa fricção entre as camadas do fluido que se movimentam com velocidades diferentes eé explicada, ao nível microscópico, como devendo-seà transferência de momento linear entre as partículas que compõem o fluido. Tecnicamente elaé caracterizada pelo coeficiente de viscosidade dinâmico, η, definido como a razão ...

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Viscosity-temperature correlation for glycerol-water solutions

Abstract: Mg/dm2 migrated. Such levels approached the BHT detection limits.

Cited by 57 publications

References 12 publications

Electron spin–lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids

Electron spin–lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids

Effect of the rotor shape on the mixing characteristics of a continuous flow Taylor-vortex reactor

Determinação da viscosidade por meio da velocidade terminal: uso da força de arrasto com termo quadrático na velocidade

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