SOME OF THE THERMODYNAMIC PROPERTIES OF AMMONIA. I. THE COMPRESSIBILITY OF AND AN EQUATION OF STATE FOR GASEOUS AMMONIA. THE VAPOR PRESSURE OF LIQUID AMMONIA

1930 ◽  
Vol 52 (1) ◽  
pp. 6-14 ◽  
Author(s):  
James A. Beattie ◽  
Charles K. Lawrence
2018 ◽  
Vol 40 (4) ◽  
pp. 387-395
Author(s):  
Phan Thi Thu Huong ◽  
Lai Ngoc Anh

This paper presents the study on the determination of the thermodynamic properties of Cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) with the BACKONE equation of state. The BACKONE's characteristic temperature T0, characteristic density ρ0, anisotropy factor α, and reduce quarupole moment Q*2 were found by fitting the BACKONE EOS to experimental data of vapor pressure and saturated liquid density. All thermodynamic properties such as vapor pressure, pressure in gaseous phase, saturated liquid density, and liquid density can be determined easily from the found molecular characteristic properties. Thermodynamic properties of the R1234ze(Z) were evaluated with available experimental data. Average absolute deviations between calculated vapor pressure data and experimental data were 0.43%. Average absolute deviations between calculated saturated liquid density data and experimental data were 0.43%. In the prediction of the thermodynamic properties, average absolute deviations between calculated liquid density data and experimental data were 0.68% and average absolute deviations between calculated gas density data and experimental data were 1.6%.


1964 ◽  
Vol 86 (3) ◽  
pp. 320-326 ◽  
Author(s):  
E. S. Nowak

A parametric equation of state was derived for water and water vapor in the critical region from experimental P-V-T data. It is valid in that part of the critical region encompassed by pressures from 3000 to 4000 psia, specific volumes from 0.0400 to 0.1100 ft3/lb, and temperatures from 698 to 752 deg F. The equation of state satisfies all of the known conditions at the critical point. It also satisfies the conditions along certain of the boundaries which probably separate “supercritical liquid” from “supercritical vapor.” The equation of state, though quite simple in form, is probably superior to any equation heretofore derived for water and water vapor in the critical region. Specifically, the deviations between the measured and computed values of pressure in the large majority of the cases were within three parts in one thousand. This coincides approximately with the overall uncertainty in P-V-T measurements. In view of these factors, the author recommends that the equation be used to derive values for such thermodynamic properties as specific heat at constant pressure, enthalpy, and entropy in the critical region.


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