Extended corresponding states model for fluids and fluid mixtures

An improved Helmholtz energy model for non-polar fluids and their mixtures. Part 2: Application to mixtures of non-polar fluids

“…The amount of data used in this fitting comprised about 30% of the total p T data involved in this study. The relationships for the calculation of thermodynamic properties are presented in the Appendix A, and the analytical expressions for the partial derivatives of the mixture Helmholtz energy had been given by Estela-Uribe and colleagues in [24]. For the calculation of isobaric heat capacities and speeds of sound, the following correlations for the perfect-gas isochoric heat capacity were used: Setzmann and Wagner [12] for methane, Estrada-Alexanders and Trusler [25] for ethane, Trusler and Zarari [26] for propane, Span et al [27] for nitrogen and Span and Wagner [28] for carbon dioxide.…”

An improved Helmholtz energy model for non-polar fluids and their mixtures. Part 3: Application to natural gases and related systems

“…The thermodynamic properties of interest are calculated from relationships involving partial derivatives of the Helmholtz energy given in the Appendix and the analytical expressions for those partial derivatives had been given by Estela-Uribe and co-workers [13]. The calculation of caloric properties requires the perfect-gas isochoric heat capacity, c pg V,m .…”

An Extended Equation of State Modeling Method I. Pure Fluids

“…Lately, the ECS method was revisited by some authors [8][9][10][11][12]17], who independently determined the shape functions through a minimization procedure using experimental data of various properties for the fluid of interest, making the method similar to the classical multiproperty fitting approach [1][2][3]. In such a way both the shape functions become available as continuous analytical functions of temperature and density.…”

“…In recent times, the extended corresponding states (ECS) modeling technique [4][5][6][7][8][9] was also extensively studied to verify whether it could be improved to obtain a further method for the development of wide-range fundamental EoSs. A new heuristic procedure descending from the conventional ECS technique was recently proposed for the haloalkanes in a predictive mode [10] and in a correlative mode [11]; moreover, a widerange fundamental EoS dedicated to fluoropropane (R227ea) was obtained [12].…”