A generalised perturbation-based equation of state for thermodynamic modelling of fluids over a wide range of density. (2nd November 2018)

• Record Type: Journal Article
• Authors: Sohrabi Mahboub, Mahdi; Farrokhpour, Hossein
• Is Part Of: Physics and chemistry of liquids. Volume 56:Number 6(2018)
• Page Start: 730
• Page End: 750
• Publication Date: 2018-11-02
• Subjects: Perturbation theory -- equation of state -- effective hard-sphere diameter -- average effective pair potential -- isotherm regularity; Liquids -- Periodicals; 530.4205
• DOI: 10.1080/00319104.2017.1381956
• Languages: English
• ISSNs: 0031-9104

Abstract

ABSTRACT: A new generalized perturbed thermodynamic nonlinear isotherm regularity (GPTNLIR) equation of state (EoS) has been proposed for the fluids over the entire density range from gas to liquid. The GPTNLIR has been derived on the basis of an effective nearest neighbor pair interaction of an extended average effective pair potential (AEPP) in the framework of the thermodynamic perturbation theory (TPT). The selected AEPP is an extended Lennard-Jones (12, 6, 3) type which considers the repulsive, dispersion, dipole-dipole and longer-range interactions between pair molecules, respectively. Based on the EoS, a non-linear relationship exists between ( Z – Z CS ) v 2 and ρ for each isotherm of fluid, where Z is the compression factor, v= 1/ ρ is the molar volume, Z CS is Carnahan–Starling (CS) expression for the compression factor of the reference fluid with the temperature-dependent effective hard-core diameter ( σ eff ). The validity of EoS against the experimental p – v – T data were tested for a variety of fluids, including polar, non-polar, hydrogen bonded and quantum fluids. This EoS provides the estimation of σ eff at T > T c, T = T c and T < T c, in which T c is critical temperature, for each real fluid using its experimental p – v – T data and the extension of TPT theory as well.