Thermodynamic Properties of Saturated Liquid and Vapor for Selected Refrigerants

2017 ◽  
pp. 681-689
Keyword(s):  
Thermodynamic Properties ◽  
Saturated Liquid

A New Approach in Approximating Thermodynamics Properties in Compressed Liquid Region

2008 ◽  
Author(s):  
Amir Karimi ◽  
Isa Tan
Keyword(s):  
Thermodynamic Properties ◽  
Internal Energy ◽  
Saturation Pressure ◽  
Approximation Formula ◽  
Liquid Region ◽  
Saturated Liquid ◽  
Thermodynamics Properties ◽  
Compressed Liquid ◽  
The Right ◽  
Current Approximation

Currently it is a common practice to use saturated liquid properties to approximate thermodynamics properties of fluids in the compressed liquid region. In this practice it is assumed that specific volume, internal energy, and entropy of fluids in the compressed liquid region are functions of temperature only and pressure practically has very little or no effect on these properties. Therefore, these properties at a given temperature and pressure are approximated by the saturated liquid properties at the given temperature. In the current literature the approximation formula given for enthalpy in the compressed liquid region is expressed as h(T, p) = hf (T) + vf (T) [p – psat (T)], where the aim of the second term on the right hand side of the equation is to improve the accuracy of the approximation, when pressure is much greater than the saturation pressure. However, in a recent study of thermodynamic properties of water, Kostic has shown that the second term in the equation improves the accuracy of the approximation of the enthalpy only at temperatures below 100 °C. In fact, he has shown that the second term increases the error when the formula is used to approximate the enthalpy of water in the compressed liquid region at intermediate and high temperatures. Kostic’s investigation is expanded in this paper to include substances other than water. The study shows that in many situations pressure has a bigger influence on the internal energy than it does on enthalpy of fluids in the compressed liquids. This paper demonstrates that the current practice of approximating properties of fluids in the compressed liquid region is not accurate at all range of temperatures and pressures. It establishes the range of pressures and temperatures for which the current approximation method could be used with reasonable accuracies. It also proposes a new scheme for the approximation of thermodynamic properties in the compressed liquid region.

New Equations for the Thermodynamic Properties of Saturated Water in Both the Liquid and Vapour Phases

1967 ◽  
Vol 9 (1) ◽  
pp. 24-35 ◽  
Author(s):  
M. R. Gibson ◽  
E. A. Bruges
Keyword(s):  
Thermodynamic Properties ◽  
Chebyshev Polynomials ◽  
Vapour Pressure ◽  
Temperature Relationship ◽  
National Bureau ◽  
Tabular Form ◽  
Saturated Liquid ◽  
Saturated Water ◽  
First Time

Equations in the form of Chebyshev polynomials are presented which enable the thermodynamic properties of saturated water in its liquid and vapour phases to be calculated in a systematic manner. In the equations defining the pressure-temperature relationship the authors have made allowance for certain unpublished observations of the National Bureau of Standards and these are considered in the section relating to vapour pressure. It is believed that the assembly of equations specify for the first time the saturated liquid and vapour boundaries whose properties have previously only been available in tabular form.

A Simplified Presentation of Equations for the Thermodynamic Properties of Dichlorodifluoromethane, CCl2F2 (Refrigerant-12)

1969 ◽  
Vol 11 (4) ◽  
pp. 376-383
Author(s):  
R. W. Haywood
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Characteristic Equation ◽  
Single Phase ◽  
Saturation Pressure ◽  
Phase Region ◽  
Pure Substance ◽  
Coherent System ◽  
Saturated Liquid ◽  
System Of Units

The paper commences with a general treatment illustrating the advantages of writing the equation of state of a pure substance in characteristic (canonical or fundamental) form, from which expressions for all other thermodynamic properties can be written down in terms only of the characteristic function and its partial derivatives. In this way, thermodynamic consistency between the equations for the different properties is automatically ensured. The initial difficulties in constructing an equation of state in characteristic form are briefly discussed, and it is shown how the characteristic equation may be built up from an existing p-v-T equation of state and an equation for the specific heat capacity at zero pressure. An existing set of equations for the single-phase region of Refrigerant-12 is transformed in this way into a single characteristic equation of state from which, through given simple expressions, all other thermodynamic properties may be computed. The equation of state is expressed dimensionlessly in reduced co-ordinates so that it may be used with equal facility in any coherent system of units. For the sake of completeness, other existing equations for the saturation pressure and for the saturated liquid have been put into dimensionless form and are given in the paper.

Thermodynamic Properties of CS and Solutions of Sulfur in Carbon-Saturated Liquid Iron

JOM ◽  
1957 ◽  
Vol 9 (5) ◽  
pp. 690-694 ◽  
Author(s):  
C. J. B. Fincham ◽  
R. A. Bergman
Keyword(s):  
Thermodynamic Properties ◽  
Liquid Iron ◽  
Saturated Liquid

scholarly journals BACKONE equation of state for Cis-1, 3, 3, 3-tetrafluoropropene (R1234ze(Z))

2018 ◽  
Vol 40 (4) ◽  
pp. 387-395
Author(s):  
Phan Thi Thu Huong ◽  
Lai Ngoc Anh
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Vapor Pressure ◽  
Characteristic Temperature ◽  
Liquid Density ◽  
Saturated Liquid ◽  
Density Data ◽  
Factor Α ◽  
Saturated Liquid Density

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%.

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