Description of SF6 behavior within the state range from the triple point to supercritical fluid

Bezverkhy, P. P.; Martynets, V. G.; Matizen, É. V.; Каплун, А. Б.; Мешалкин, А. Б.

doi:10.1134/s0869864312040166

Cited by 8 publications

(8 citation statements)

References 21 publications

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“…The scaling (singular) part of the equation of state p scal , comprising besides values p c , ρ c , and T c fitting constants q, k, M -a p , and C 1 , taking into account the expansion of the integral member [20], has the form…”

Section: Equation Of Statementioning

confidence: 99%

“…For such a function, we selected [20] Y = ωerfc( |τ|)exp(-μ(Δρ) 2 ), (1) where ω = ρ/ρ с and erfc( |τ|) is the Laplace function (error function). Function (1) is associated with a proba bility of W ~ exp(-λτ 2 -μ(Δρ) 2 ) of the occurrence (damping) of fluctuations of temperature and density at some point of state T, ρ [5].…”

Section: Equation Of Statementioning

confidence: 99%

“…The regular part p reg of the combined equation of state is a modification of p reg , applied previously in [20], and contains eight system dependent (adjust able) constants A 1 -A 8 :…”

Section: Equation Of Statementioning

confidence: 99%

“…A unified thermal equa tion of state, approximating precision P-ρ-T data with sufficient accuracy, can give a description of the caloric properties with an accuracy not worse than the experimental and calculation of the properties of the system in regions where there are no experimental data or the obtaining of them is difficult. Modification of the regular eight constant EOS [11,20], as shown in this article, is suitable to describe the caloric prop erties of СО 2 and SF 6 .…”

Section: Introductionmentioning

confidence: 99%

“…These include the classic cubic EOS of the van der Waals type having a critical point; among the contemporary examples, the three constant Kaplun-Meshalkin EOS [17] and the Patel Teja EOS [8] are the most appropriate. Of the large number of regular few con stant EOS (four or more adjustable constants), let us mention only those having some physical justification: cubic EOS [18], which is a combination of the equa tions described in [17] and [8] (five constants), and the recently proposed EOSs, unified for the gas and liquid states of matter [19,20] (seven to nine constants). However, regular models of EOSs, despite fairly accu rate predictions of the thermodynamic properties away from the critical point, do not describe the singu lar behavior of the thermodynamic functions in the critical region.…”

Section: Introductionmentioning

confidence: 99%

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Description of heat capacity C v of simple liquids using a thermal equation of state including regular and scaling parts

2015

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The p,ρ,T data for CO 2 are approximated in the ranges of 0 < ρ/ρ c <2, 217 < T < 430 K, and 0 < p ≤ 25 MPa and for SF 6 in the ranges of 0 < ρ/ρ c < 2.5, 225 < T < 340 K, and 0 < p ≤ 10 MPa using a new unified equation of state. In this equation, pressure p is an explicit function of ρ and T. It includes a new reg ular part to approximate p,ρ,T data in the liquid and gaseous regions of state outside the critical region, a sin gular part that is a scaling equation of state for the critical region, and a crossover function for combining these equations. The regular part consists of the sum of eight terms with eight constants, three of which are deter mined by the conditions at the critical point. The total number of system dependent constants is fourteen, including the critical values of p, ρ, and T. In the scaling part of the equation of state, the critical exponents of the three dimensional Ising model are used. The mean square error of the description by pressure of the p,ρ,T data for CO 2 is ±0.63%, and for the p,ρ,T data obtained for SF 6 , it is ±0.70% over the entire range of gas and liquid states. Using the constants of the combined equation, heat capacity C v is calculated at isoch ores, isotherms, and a binodal, including those in the critical region. The calculation results describes the known experimental data of C v with an error of ±8%.

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Section: Equation Of Statementioning

confidence: 99%

Section: Equation Of Statementioning

confidence: 99%

“…The regular part p reg of the combined equation of state is a modification of p reg , applied previously in [20], and contains eight system dependent (adjust able) constants A 1 -A 8 :…”

Section: Equation Of Statementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%