Abstract: A combined equation of state of methane in real variables (pressure p, temperature T, density ρ) is proposed that allows calculations of heat capacities Cv , Cp, and speed of sound W in explicit form in single-phase states, including the critical region. The equation contains a regular part in the form of Bender’s equation for p(ρ,T) with 19 coefficients, a scaling part with 6 coefficients, and a crossover function in explicit form (2 coefficients). The coefficients are determined from a CH4 p, ρ,T data array up to 30 MPa. Data on Cv, Cp, and W are not involved, except for the Cv(T) dependence in the ideal gas state and value at 100 K on the liquid branch of the boundary curve. In the regular region, the calculated values of Cv, Cp, and W are close to the experimental and tabulated values. Discrepancies with the tabular values are no more than 5% in the critical region. The RMS error for p is σp = 0.8%, and error for Cv is no more than 5%. Results from calculations are compared to crossover equations of state for CH4. It is concluded that the proposed model of the combined equation of state is preferable for calculating the thermophysical properties of methane.

Cite: Bezverkhii P.P. , Matskevich N.I.
A Combined Equation of State for Methane, Based on Bender’s Regular Equation with a Scaling Part in Explicit Form up to 50 MPa
Russian Journal of Physical Chemistry A. 2024. V.98. N1. P.14-24. DOI: 10.1134/S0036024424010047 WOS Scopus РИНЦ OpenAlex

Original: Безверхий П.П. , Мацкевич Н.И.
Комбинированное уравнение состояния метана на основе регулярного уравнения Бендера с масштабной частью явного вида до 50 МПА
Журнал физической химии. 2024. Т.98. №1. С.16-25. DOI: 10.31857/s0044453724010036 РИНЦ OpenAlex

Dates:

Submitted:	Jun 29, 2023
Accepted:	Jul 10, 2023
Published print:	May 20, 2024

Identifiers:

Web of science:	WOS:001237115500041
Scopus:	2-s2.0-85193709729
Elibrary:	67598021
OpenAlex:	W4398143055

Citing: Пока нет цитирований

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