| 초록 |
A hard-sphere-chain (HSC) equation of state can be used as the reference system in place of the hard-sphere reference used in most existing equations of state for fluids. In 1994, Song et al. proposed a perturbed hard-sphere-chain (PHSC) equation of state which is in better agreements with computer simulation data than those of the previous HSC thermodynamic models. However, when compared with Monte Carlo simulation data for the compressibility factors of hard-spheres, PHSC equation of state slightly underestimates the pressure especially in high-density region. Kim and Bae modified the PHSC equation by introducing the form of the radial distribution function proposed by Chapman et al. into the bonding part in reference term. This model also better illustrates the density dependence of the reference term than that of PHSC equation of state when plotting the ratio of the repulsive contribution to the compressibility factor for a chain molecule to that for a monomer molecule versus the reduced density. However, two PHSC equations of state are still poor in representing the attractive contributions as both equations of state adapted the simplest type of van der Waals attractive form as the perturbation term. Bokis et al. suggested a simple expression for the perturbation term by correlating the Monte Carlo simulation data directly.In this work, we introduce this perturbation term into the modified PHSC equation of state to account for the attractive contributions better than those of existing HSC models. We then compare the model with the PHSC equations of state through computer simulation data for a one-component hard-sphere chain system and binary mixtures of hard-sphere chains. We also predict VLE and LLE of fluids including polymer solution.
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