Investigation of the gas density, the liquid density and the gravitational effect in the critical region of C6F6

• Main Authors: Ustyuzhanin, E E, Ochkov, V F, Rykov, V A, Rykov, S V
• Format: Conference Proceeding
• Language: English
• Subjects: Critical phenomena; Earth gravitation; Gamma ray beams; Gas density; Gravitational effects; Microgravity; Order parameters; Physics; Thermodynamic properties
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1556/1/012057

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 (ρl), the gas density (ρg), the order parameter, the mean diameter of the coexistence curve, etc). We have paid attention to well-known experimental (ρl, ρg, T) data of C6F6, which are got in a wide temperature interval. One more object is investigated in the work. It is a height dependence of the density, ρ(h), in the critical region, here h is the distance of the gamma-ray beam from the bottom of the cell, in which the sample is placed. These (ρ, h, T) data are got at the earth gravity (g = 9.8 m/s2). In our work, it is studied a behavior of the sample at a special condition: the gravitational effect is reduced in the cell with the sample. In the case of the microgravity, we have elaborated an equation, which expresses a meniscus position in two-phase sample in the critical region. Combined models are elaborated to approximate (ρl, ρg, T) data of C6F6 in the wide temperature interval including the critical region. These models meet the scaling theory of critical phenomena.