Thermodynamic properties of methane in the critical region

The admissibility domain of rarefaction shock waves in the near-critical vapour–liquid equilibrium region of pure typical fluids

“…Levelt-Sengers (1970). Notable examples of anomalous trends include the weak divergence of the isochoric heat capacity c v , the strong divergence of the isothermal compressibility κ T ≡ −1/v(∂v/∂P) T , the weak approach to zero of the thermodynamic (zero-frequency) sound speed at the critical point and the strong divergence of the thermal conductivity, see for example the works of Michels, Sengers & van der Gulik (1962), Levelt-Sengers, Kamgar-Parsi & Sengers (1983a), Levelt-Sengers, Morrison & Chang (1983b), Albright et al (1987), Kurumov et al (1988) and Wyczalkowska & Sengers (1999) and listed references therein reporting corresponding experimental data. The Helmholtz free energy is non-analytic at the critical point, as a direct consequence of the divergence of c v near the critical point.…”

“…Starting from (2.1) to (2.5), Nannan et al (2013) showed that: (i) Γ weakly diverges to large positive values as the critical point is approached from the single-phase region, namely, the power of divergence of Γ as a function of the dimensionless temperature difference with respect to the critical temperature is less than unity, and (ii) Γ weakly diverges to large negative values as the critical point is approached along the critical isochore from the vapour-liquid equilibrium region, thus implying the existence of a domain of so-called negative nonlinearity in any typical fluid, where Γ < 0. Figure 1(b) shows the thermodynamic region encompassing states featuring negative Γ for methane (CH 4 ), calculated using the substance-specific parameters reported by Kurumov et al (1988). In particular, along the dew line, one has…”

“…Additionally, for maximum Mach shocks (red dashed line), the continuous red line represents the pressure jump across the wave, and the blue dashed-dotted line illustrates the associated entropy increase across the wave. The fluid is methane and thermodynamic properties are determined with the EoS of Kurumov et al (1988). Also jump conditions for the exemplified shock wave A-B are shown.…”

“…The locus θ = −1 is the dew line, θ = 1 is the bubble line. The region limited by the solid blue lines represents the validity domain of the scaled fundamental EoS for methane as reported by Kurumov et al (1988) under the hypothesis of thermodynamic equilibrium. (b) Pressure-volume thermodynamic plane.…”

Rarefied Natural Gas Transport

“…Then you can use the formulas and the properties to present further properties of other hydrocarbons, such as ethane, propane, butane, etc., to calculate further physical properties of natural gases in most common operating states, and to conduct further analyses of theoretical and experimental researches. Various tests have been conducted to determine  , k , p c , and  of methane at different working pressures or temperatures (Mann & Dickins 1931;Johnston & McCloskey 1940;Clarke & Smith, 1969;Jansoone et al, 1970;Vennix et al, 1970;Younglove, 1974;Gammon & Douslin, 1976;Kerley, 1980;Kurumov et al, 1988;Friend et al, 1989;Jin et al, 1992;Pátek & Klomfar, 2002;Hurly et al, 2003;Schley et al, 2004;Viswanathan, 2007). Except for density, temperature was found to be a relatively important factor in the gaseous state.…”