Martin-Hou equation

Thus, pressure-explicit equations of state for pure substance 1 (for the first integral) and for the gas mixture (the second integral) are required. Five different equations of state have been used in the analysis of this system (1) the five-constant Beattie-Bridgeman equation (2) the eight-constant Benedict-Webb-Rubin equation (3) the twelve-constant modified Martin-Hou equation and (4) and (5), the virial equation using two sets of virial coefficients. The first of these uses pure-substance second and third virial coefficients calculated from the Lennard-Jones 6-12 potential with interaction coefficients determined by the method of Ewald [ ]. The second set differs only in the second virial coefficients and interaction coefficient, these being found using the Kihara potential Solutions of the theoretical equa-... 

Values of Cp, Cy, internal energy E, enthalpy H, and entropy S of the real gas are also available from calculations using reference values for the ideal gas and a modified Benedict-Webb-Rubin equation of state, the melting curve, vapor and liquid density curves, and the vapor pressure curve mentioned above. They are parameterized in the same way (along coexistence lines and isochores) as the pgT data, see p. 202 [2]. In a similar manner, H and S were calculated earlier from a Martin-Hou equation of state, see p. 202 [3]. 

A thermod5mamic model to simulate ammonia S5mthesis is described in [117]. It includes the use of the so-called Martin—Hou equation of state for the gas phase, whereas a simple Van Laar model is used to model the phase equilibrium including the solubility of the gases. 

Brown measured the density of perfluoropropane (347 to 439 K 17 to 57 bar) and derived constants for a Martin-Hou equation of state. Dantzler and Knobler deduced values of B(233 to 373 K) from this equation. 

Miscellaneous Compounds. Hajjar and MacWood deduced Bp of sulphur hexafluoride at 70 and 100 °C from measurements of gas density at low pressure. Mears et al. measured the density of sulphur hexafluoride (25 to 130 °C, 10 to 75 bar) and expressed the results in terms of a Martin-Hou equation of state they also compared derived values of B and C with literature values. Haworth and Sutton measured Bp of trimethylamine at 25 °C. 

The tables of the values of v, A, and s for gaseous Freon-20 were calculated in Ref. [1.58] using Eq. (1.15) at T = 280-750 K and p = 0.1-200 atm. It is essential to note that the numerical values of the constants A,, 5,, and Q in the Martin-Hou equation are strongly dependent on the values of the characteristic parameters. Additionally, the analytical relations used to determine these constants can be diverse see, for example. Ref. [1.1]. It is possible to evaluate the reliability of the calculated tables in Ref. [1.58] using, for example, the generalized BWRC equation, which was discussed in the introduction. 

Twelve coefficients for the Martin-Hou equation of state can be computed using analytical relations if the critical parameters, Boyle point temperature. 

In Figs. 1.1 to 1.3 the equilibrium % NH3 are shown as a function of temperature at different pressures and at 0%, 10% and 20% inert (methane and argon) content, respectively. The fugacity coefficient ratio is calculated by the present author using the Martin-Hou equation of state, see [36]. Of course, other equations of state could have been used for calculating this coefficient. 

For the modeled high pressure Westinghouse experiments, the system conditions were such that the SFe vapor properties deviated a considerable amount from ideal gas property relations. Because of the ideal gas property inaccuracies, non-ideal gas property models for SFe vapor were developed and implemented in the RELAP5/M0D3 code calculations. These models were developed for the specific volume, v, the coefficient of thermal expansion, isothermal compressibility, /c, and heat capacity at constant pressure, Cp. The non-ideal property models were obtained using a five coefficient Martin-Hou type equation of state and thermodynamic relations [8]. 

The coefficients of this equation are obtained by a method proposed by Martin and Hou (1955), and when v is in liters per mole, p is in atmospheres, and T is in Kelvins, they are equal to... 

Several versions of equations of state of type (0.2)-(0.5) are known. The coefficients of these equations were determined from pvT data of Hou and Martin [4.25] covering the region t = 0.74-1.3, o) = 0.03-1.9. 

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