RT Journal Article
T1 Application of the generalised SAFT-VR approach for long-ranged square-well potentials to model the phase behaviour of real fluids
A1 dos Ramos, María Carolina
A1 Docherty, Hugh
A1 Jiménez Blas, Felipe
A1 Galindo, Amparo
AB In a recent generalisation of the SAFT-VR equation of state the method was extended so as to deal with wide square-well ranges, namely, 1.2 ≤ λ ≤ 3.0 [B. H. Patel, H. Docherty, S. Varga, A. Galindo, and G. C. Maitland. Mol. Phys., 103(1), 129–139, 2005.]. In this work, this equation is used to revisit the adjustment of intermolecular model parameters, with special emphasis on substances where the upper boundary of the potential range (λ = 1.8) has been previously reported or may be expected on grounds of the polar nature of the molecules. For this purpose, we follow the work of Clark et al. [G. N. I. Clark, A. J. Haslam, A. Galindo, and G. Jackson. Mol. Phys., 104(22-24), 3561–3581, 2006] and study a relative least squares objective function and the percentage absolute average deviation (%AAD) to determine the intermolecular model parameters (m, λ, σ, ε/kB, εhb/kB and rc) by comparison to experimental vapour-pressure and saturated liquid density data. In order to ensure in each case that the global minimum is identified, the dimensionality of the problem is reduced by discretising the parameter-space. Applying this method to the study of argon, nitrogen, benzene, carbon dioxide, carbon monoxide, n-alkanes, the refrigerant R1270, water, hydrogen chloride and hydrogen bromide, we find that the optimal models always present square-well ranges λ < 1.8, meaning that an upper bound value of λ = 1.8 (as set in the original approach) for the square-well range is sufficient to model real fluids. Accurate intermolecular potential models with ranges higher than 1.8 are also identified, but we find that these do not usually correspond to the global minimum of the objective function considered.
PB Elsevier
SN 0378-3812
YR 2009
FD 2009
LK http://hdl.handle.net/10272/17580
UL http://hdl.handle.net/10272/17580
LA eng
NO dos Ramos, M. C., Docherty, H., Blas, F. J, Galindo, A.: "Application of the generalised SAFT-VR approach for long-ranged square-well potentials to model the phase behaviour of real fluids", Fluid Phase Equilibria Vol. 276, págs. 116-126, (2009). DOI: 10.1016/j.fluid.2008.09.025
NO M.C.dR. acknowledges the Programme Alßan from European Union Programme of High Level Scholarships for Latin America (identification number E03D21773VE) for a Fellowship. Authors also acknowledge financial support from project number FIS2007- 66079-C02-02 of the Spanish Dirección General de Investigación. Additional support from Universidad de Huelva and Junta de Andalucía is also acknowledged.
DS Repositorio Institucional de la Universidad de Huelva
RD 31 may 2026