Christian Boned

High-Pressure Measurements of the Viscosity and Density of Two Polyethers and Two Dialkyl Carbonates

The viscosity and density of four pure liquid compounds (dimethyl carbonate, diethyl carbonate, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether) were measured at several temperatures between 283.15 and 353.15 K. The density measurements were performed up to 60 MPa with an uncertainty of 1×10−4g·cm−3. The viscosity at atmospheric pressure was measured with an Ubbelohde-type glass capillary tube viscometer with an uncertainty of ±1%. At pressures up to 100 MPa the viscosity was determined with a falling ball viscometer with an uncertainty of ±2%. The density (410 experimental values) and viscosity data (184 experimental values) were fitted to several correlation equations.

Determination of the viscosity of various hydrocarbons and mixtures of hydrocarbons versus temperature and pressure

The dynamic viscosityη and densityρ of 10 pure substances and three binary systems were measured as a function of temperatureT (298.15, 313.15, 333.15, 353.15, and 363.15 K.) and pressureP (⩽100 MPa). The pure substances were toluene,p-xylene,m-xylene,o-xylene, methylcyclohexane, methylnaphthalene, decahydronaphthalene, phenyldodecane, heptamethylnonane, and tetramethylpentadecane (pristane). The three binaries were toluene + tetramethylpentadecane, toluene + methylnaphthalene, and toluene + heptamethylnonane, for molar fractionsx of toluene ranging between 0 and 1. The three binaries are highly “contrasted” systems, i.e., systems in which the viscosities of the pure components are very different for eachP, T pair. In all, 547 experimental determinations were carried out (279 experimental data for viscosity of the pure substances and 268 data concerning the mixtures: x⊋0 and 1).

A new free volume model for dynamic viscosity and density of dense fluids versus pressure and temperature

Abstract This article presents a model based on the free volume concept, which describes the variations of dynamic viscosity and density versus temperature and pressure for the dense fluids (density > 200 kg · m−3). This model involves 6 constants for each pure compound: 3 for viscosity and 4 for density (1 constant is common to both quantities). Moreover if the viscosity and the density are known at a pressure and temperature of reference, it is sufficient to use 4 constants per pure compound. If the density is assumed to be known the model fits the viscosity data with an average absolute deviation of 3.8% for 3297 data corresponding to 41 very different pure compounds (alkanes, alkylbenzenes, cycloalkanes, alcohols, carbon dioxide, refrigerants). If the pressure is lower than 110MPa the average absolute deviation is 2.8% for viscosity (2977 points). The model gives also good results for water (3.6%). If the density is unknown, for pressures lower than 110MPa the model represents viscosity with an average absolute deviation of 3.5% and for the density the average absolute deviation is 1.5%.

Scaling of the viscosity of the Lennard-Jones chain fluid model, argon, and some normal alkanes

In this work, we have tested the efficiency of two scaling approaches aiming at relating shear viscosity to a single thermodynamic quantity in dense fluids, namely the excess entropy and the thermodynamic scaling methods. Using accurate databases, we have applied these approaches first to a model fluid, the flexible Lennard-Jones chain fluid (from the monomer to the hexadecamer), then to real fluids, such as argon and normal alkanes. To enlarge noticeably the range of thermodynamics conditions for which these scaling methods are applicable, we have shown that the use of the residual viscosity instead of the total viscosity is preferable in the scaling procedures. It has been found that both approaches, using the adequate scaling, are suitable for the Lennard-Jones chain fluid model for a wide range of thermodynamic conditions whatever the chain length when scaling law exponents and prefactors are adjusted for each chain length. Furthermore, these results were found to be well respected by the corresponding real fluids.

Measurements of the viscosity and density of three hydrocarbons and the three associated binary mixtures versus pressure and temperature

The dynamic viscosity η and density ρ of the pure substances (heptane, methylcyclohexane, 1-methylnaphthalene) and of the three associated binary mixtures (heptane+methylcyclohexane, heptane+1-methylnaphthalene, methylcyclohexane+1-methylnaphthalene) were measured as a function of temperatureT (303.15, 323.15, and 343.15 K) and pressureP(≤100 MPa). For the binary mixtures the mole fractionx of each component was successively 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, and 1. The total experimental results represent 432 different points: 54 for the pure substances and 378 for the binary mixtures (x≠0 and 1).

High-Pressure (up to 140 MPa) Dynamic Viscosity of the Methane+Decane System

The dynamic viscosity of n-decane and methane mixtures containing 31.24, 48.67, 60.00, 75.66 and 95.75% (mol%) of methane has been measured using a falling-body viscometer. The measurements (295 data points) have been performed in the temperature range 293.15 to 373.15 K and at pressures up to 140 MPa for viscosity. The data have been used to calculate the excess activation energy of viscous flow using a mixing law. Moreover, a self-referencing model, previously developed in the laboratory, gives an average absolute deviation of the viscosity of about 3% with a maximum deviation of 16%.

PρTx measurements for HFC-134a + triethylene glycol dimethylether system

Experimental densities in the compressed liquid phase are reported for 1,1,1,2-tetrafluoroethane (HFC-134a), triethylene glycol dimethylether (TriEGDME) and six of their mixtures from 293.15 to 373.15 K and at pressures up to 60 MPa. From the experimental results, we have analysed the volumetric behaviour of HFC-134a+TriEGDME. In almost all the measurement range, the density of the refrigerant is greater than that of the polyether. Furthermore, above 333.15 K the densities of the mixtures display a crossover phenomenon with composition. The excess volumes are strongly negative and asymmetrical towards high refrigerant concentrations, becoming more negative when the temperature increases and the pressure decreases.

Viscosity of binary heptane—nonylbenzene as a function of pressure and temperature: application of Flory's theory

Abstract The dynamic viscosity and density of the n-heptane+nonylbenzene binary mixture have been measured as a function of concentration, between 1 and 400 bar at temperatures 40, 60 and 80°C. The 105 experimental values were adjusted by means of the Bloomfield and Dewan relationship and Florys theory, without employing any additional adjustable parameters. The mean deviation observed is 5.7%. This shows that the range of applicability of this representation, tested successfully at atmospheric pressure, can be extended to conditions of higher pressure. For comparison, the experimental results have been tested against other laws, representative of the viscosity of mixtures, relying upon an adjustable empirical parameter.

Viscosity and Excess Volume at High Pressures in Associative Binaries

The dynamic viscosity η and the density ρ of three pure substances (water, 2-propanol, diacetone alcohol) and the three associated binaries were measured versus temperature T (303.15, 323.15, and 343.15 K) and pressure P. For the binary systems the mole fractions x of each component were, successively, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1. For viscosity the experimental results (P≤100 MPa) represent a total of 540 data points: 54 for the pure substances and 486 for the binary mixtures (x≠0 and x≠1). For density the experimental results (P≤70 MPa) represent 1260 values: 126 for the pure substances and 1134 for the binary mixtures (x≠0 and x≠1). The mixtures with water are highly associative and the curves for the variation of η with composition exhibit a maxima. The variations of the excess activation energy of viscous flow ΔGE are discussed. Moreover, the measurements of ρ are sufficiently accurate to determine the excess volumes VE versus pressure, temperature, and composition.

Reference Correlation of the Viscosity of Squalane from 273 to 373 K at 0.1 MPa

The paper presents a new reference correlation for the viscosity of squalane at 0.1 MPa. The correlation should be valuable as it is the first to cover a moderately high viscosity range, from 3 to 118 mPa s. It is based on new viscosity measurements carried out for this work, as well as other critically evaluated experimental viscosity data from the literature. The correlation is valid from 273 to 373 K at 0.1 MPa. The average absolute percentage deviation of the fit is 0.67, and the expanded uncertainty, with a coverage factor k = 2, is 1.5%.