Development of combined scaling models for liquid and gas densities at the saturation line: Structures and numerical data for SF6

• Main Authors: Vorobev, V S, Ochkov, V F, Rykov, V A, Rykov, S V, Ustyuzhanin, E E, Pokholchenko, V A
• Format: Conference Proceeding
• Language: English
• Subjects: Critical temperature; Gas density; Mathematical models; Order parameters; Parameter estimation; Saturation; Scaling; Thermodynamic properties; Transition temperature
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1147/1/012016

Some thermodynamic functions are considered in the work. They have a scaling form and connected with thermodynamic properties at the saturation line (the fluid density, the gas density, the order parameter, the mean diameter, etc). Scaling models have the area of applicability near the critical temperature. A Wegner model is valid at relative temperatures, 0 < τ < 0.02. Its structure includes scaling components with indices α and β, a linear component. A new Fisher model is suggested in 2003. Its structure includes an additional component with an index, 2β. Another model is developed in the work. The model is referred to as a combined scaling model. At first, its structure contains scaling components including a term with 2β index; secondly, there are regular components, which allowed us to increase the area of applicability up to τ ≈ 0.3. We have made numerical estimates, which are connected with parameters of the combined scaling model and based on experimental data related to the fluid and gas densities of SF6. This model is compared with an Anisimov model and with experimental data. Numerical data are got in some extrapolation region near the critical temperature. These results are analyzed.