Tongfan Sun

The thermal conductivity and viscosity of acetic acid-water mixtures

The viscosity and thermal conductivity of acetic acid water mixtures were measured over the entire composition range and at temperatures ranging from 293 to 453 K. Viscosity measurements were performed with a high-pressure viscometer and thermal conductivity was measured using a modified transient hot-wire technique. A mercury filled. glass capillary was used as the insulated hot wire in the measurements. The l iscosity data showed unusual trends with respect to composition. At it given temperature. the viscosity was seen to increase with increasing acid concentration, attain a maximum. and then decrease. The thermal conductivity, on the other hand, decreased monotonically with acid concentration. A generalized corresponding-states principle using water and acetic acid as the reference fluids was used to predict both viscosity and thermal conductivity with considerable sucres.

Solid-fluid equilibria in natural gas systems

Abstract Solid–fluid equilibria (SFE) in natural gas systems were calculated using a number of equations of state (EOS) including the Redlich–Kwong–Soave (RKS) equation, the Peng–Robinson (PR) equation, the Patel–Teja (PT) equation, and a Lennard–Jones (LJ) equation of state. A number of mixing rules were used with one of the equations of state to study the effect of the mixture model on calculations of SFE. The natural gas systems studied included n -alkanes in supercritical carbon dioxide and n -alkanes in ethane. The predictive capabilities of the equations were examined by extrapolation to high pressures and temperatures where the extrapolated results were compared with experimental results.

The transport properties of seven alkanediols

Abstract The densities of six diols with hydroxy groups on the terminal ends of the carbon chains were measured at ambient pressure and temperatures ranging from 293 to 463 K. The viscosities of the same diols were also measured at temperatures from 293 to 433 K. In addition, the thermal conductivities of seven diols were measured in the temperature range 293 – 473 K. The estimated accuracy of the measurements were ± 0.2% for density, and ± 2% for both viscosity and thermal conductivity. A model based on molecular dynamic simulations of Lennard-Jones molecules was used to successfully describe the viscosity and thermal conductivity of the diols.

Correlation and prediction of the transport properties of refrigerants using two modified rough hard-sphere models

Two methods are presented for the correlation and prediction of the viscosities and thermal conductivities of refrigerants R11, R12, R22, R32, R124, R125, R134a, R141b, and R152 and their mixtures. The first (termed RHS1) is a modified rough-hard-sphere method based on the smooth hard-sphere correlations of Assael et al. The method requires two or three parameters for characterizing each refrigerant but is able to correlate transport properties over wide ranges of pressure and temperature. The second method (RHS2) is also a modified rough-hard-sphere method, but based on an effective hard-sphere diameter for Lennard–Jones (LJ) fluids. The LJ parameters and the effective hard-sphere diameter required in this method are determined from a knowledge of the density–temperature behavior of the fluid at saturation. Comparisons with the rough-hard-sphere method of Assael and co-workers (RHS3) are shown. We also show that the RHS2 method can be used to correlate as well as predict the transport properties of refrigerants.

A simple non-classical equation of state for fluids and fluid mixtures

Abstract A method for improving the behavior of classical equations of state (EOS) in the critical region, originally proposed by Fox [J.R. Fox, Fluid Phase Equilibria 14 (1983) 45–53], has been modified in this work for the Patel–Teja (PT) EOS [N.C. Patel, A.S. Teja, Chem. Eng. Sci. 37, 463–473]. The application of the new equation (NPT) for predicting PVT and vapor pressure behavior of pure substances, as well as vapor–liquid equilibrium behavior of binary mixtures, is demonstrated. The NPT equation is simple to use and requires the same input information as the original PT equation. However, it reproduces the correct PVT behavior in the critical region. Limitations of both the PT and NPT equations in calculating the isochoric heat capacity are discussed.