An Equation of State for Compressed Water from 1 to 1000 Bar and from 0°C tO 150°C

1968 ◽  
Vol 10 (4) ◽  
pp. 319-328 ◽  
Author(s):  
M. R. Gibson ◽  
E. A. Bruges
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Dynamic Properties ◽  
Similar Type ◽  
Independent Variables ◽  
Turbine Performance ◽  
Dependent Variables ◽  
Water Turbine ◽  
Water Substance

The precision with which the thermodynamic properties of compressed water and steam are known has led, not unnaturally, to the development of equations of state suitable only for use on electronic digital computers. The equations are in the main empirical although some are highly sophisticated and lead to lengthy programs and complex sub-routines. Among such equations are those of the 1966 and 1967 Formulations of the Thermo-dynamic Properties of Ordinary Water Substance prepared by the International Formulation Committee of the International Steam Conference. The favoured form of equation has been one in which the dependent variables are enthalpy, volume and entropy and the independent variables pressure and temperature. However, this form of equation may not prove to be always the most suitable and the purpose of this paper is to describe how another type of equation, in which the dependent variable is enthalpy and the independent variables are pressure and entropy, may be established and applied. It is believed that this particular type of equation, relating as it does the three most important parameters in pump and turbine performance, has special qualities for design and efficiency calculations. By way of example the efficiency of a water turbine is evaluated according to the ‘thermodynamic method’ described by Thom (2). A concluding section outlines the further steps being taken by the authors to provide a similar type of equation over ranges of pressure and temperature up to 1000 bar and 1000°C.

Thermodynamic properties of liquid mixtures: Selection of the pure liquid parameter

1974 ◽  
Vol 27 (3) ◽  
pp. 647 ◽  
Author(s):  
DV Fenby ◽  
NF Pasco
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Liquid Mixtures ◽  
Pure Liquid ◽  
Excess Thermodynamic Properties ◽  
Pure Fluids ◽  
Liquid Parameter ◽  
Selection Of

There has recently been a revival of interest in theories of liquid mixtures based on analytic equations of state for pure fluids. We have shown that the method used to determine the parameters of the pure-liquid equation of state has a significant effect on the excess thermodynamic properties obtained from such theories.

Equations of state for fluids based on hard sphere repulsion

2015 ◽  
Vol 29 (13) ◽  
pp. 1550089 ◽  
Author(s):  
Minhui Shan ◽  
Jianxiang Tian
Keyword(s):  
Equation Of State ◽  
Thermodynamic Properties ◽  
Hard Sphere ◽  
Equations Of State ◽  
The Past ◽  
Complex Interactions ◽  
Structures And Properties ◽  
The One ◽  
Real Fluids

As is well-known, the structures and thermodynamic properties of fluids are determined by the complex interactions, i.e., the repulsive one and the attractive one, among particles. The simplest equation-of-state (EOS) model maybe the one of hard sphere repulsion plus or multiplying some attraction. Followed by the rapid promotion of the accuracy of hard sphere EOS in the past dozens of years, one question rises as whether more accurate hard sphere repulsion derives better prediction of the structures and properties of fluids with a special attraction. In this work, we used two repulsions with clearly different accuracy and some attractions to construct series equations of state (EOSs) for real fluids, and then we discussed the saturated properties at liquid–gas equilibrium. We found that the answer to the question aforementioned is not definitely standing.

Effects of the Different Temperature Scales on the Calculation of the Thermodynamic Properties of Water Substance

1969 ◽  
Vol 11 (5) ◽  
pp. 521-525
Author(s):  
M. R. Gibson
Keyword(s):  
Thermodynamic Properties ◽  
Equations Of State ◽  
Simple Method ◽  
Temperature Scales ◽  
Thermodynamic Temperatures ◽  
Water Substance

Attention is drawn to the fact that the derivation of so-called ‘Thermodynamic Temperatures’ by the addition of the quantity, 273·15, to temperatures referred to the IPTS leads to discrepancies in the values of the thermodynamic properties calculated from equations of state by means of the thermodynamic relations. These differences are shown to be significant when compared with the tolerances in the 1963 International Skeleton Tables and a simple method of avoiding this error is described.

Renormalization Group Theory Applied to the CPA Equation of State: Impacts on Phase Equilibrium and Derivative Properties

2019 ◽  
Author(s):  
Gabriel Silva ◽  
Charlles Abreu ◽  
Frederico W. Tavares
Keyword(s):  
Renormalization Group ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Chemical Engineering ◽  
Equations Of State ◽  
Thermodynamic Description ◽  
Critical Conditions ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Vapor Liquid

Calculation of thermodynamic properties such as vapor-liquid phase behavior with equations of state is largely and successfully employed in chemical engineering applications.<br>However, in the proximities of the critical point, the different density-fluctuation scales inherent to critical phenomena introduce significant changes in these thermodynamic properties, with which the classical equations of state are not prepared to deal.<br>Aiming at correcting this failure, we apply a renormalization-group methodology to the CPA equation of state in order to improve the thermodynamic description in the vicinity of critical points.<br>We use this approach to compute vapor-liquid equilibrium of pure components and binary mixtures, as well as derivative properties such as speed of sound and heat capacity.<br>Our results show that this methodology is able to provide an equation of state with the correct non-classical behavior, thus bringing it in consonance with experimental observation of vapor-liquid equilibrium and derivative properties in near-critical conditions.

scholarly journals Modelling 3D Steam Turbine Flow Using Thermodynamic Properties of Steam Iapws-95

2016 ◽  
Vol 23 (1) ◽  
pp. 61-67 ◽  
Author(s):  
A.V. Rusanow ◽  
P. Lampart ◽  
N.V. Pashchenko ◽  
R.A. Rusanov
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Steam Turbine ◽  
Equations Of State ◽  
Three Dimensional ◽  
Steam Turbines ◽  
Perfect Gas ◽  
Van Der Waals Equation ◽  
Approximate Equations

Abstract An approach to approximate equations of state for water and steam (IAPWS-95) for the calculation of three-dimensional flows of steam in turbomachinery in a range of operation of the present and future steam turbines is described. Test calculations of three-dimensional viscous flow in an LP steam turbine using various equations of state (perfect gas, Van der Waals equation, equation of state for water and steam IAPWS-95) are made. The comparison of numerical results with experimental data is also presented.

Assessment of the Computing Time for the IAPWS-IF97 Equations

2006 ◽  
Vol 129 (3) ◽  
pp. 885-887 ◽  
Author(s):  
Kiyoshi Miyagawa
Keyword(s):  
Thermodynamic Properties ◽  
Simple Structure ◽  
Computer Systems ◽  
Computing Time ◽  
Ordinary Water ◽  
Independent Variables ◽  
Modern Computer ◽  
Water Substance

Computing times of equations based on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97) were tested. Modern computer systems are optimized for “simple” computational operations, which favors the simple structure of IAPWS-IF97. Provision of “backward equations,” which are approximation of inverse equations, is one of the features of IAPWS-IF97. The backward equations showed much shorter computing times than iterative routines, which had been used to calculate with several independent variables. IAPWS-IF97 is faster than the equations of IAPWS Formulation 1995 for the Thermodynamic properties of Ordinary Water Substance for General and Scientific Use (IAPWS-95) by factors 70 to 200 times.

Reference correlations for the viscosity and thermal conductivity of fluids over an extended range of conditions: hexane in the vapor, liquid, and supercritical regions (IUPAC Technical Report)

2015 ◽  
Vol 87 (3) ◽  
pp. 321-337
Author(s):  
Richard A. Perkins ◽  
Marcia L. Huber ◽  
Marc J. Assael ◽  
Efthimia K. Mihailidou ◽  
Sofia K. Mylona ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Equations Of State ◽  
Reliable Data ◽  
Theoretical Knowledge ◽  
Technical Report ◽  
Wide Range ◽  
Extended Range ◽  
Vapor Liquid

AbstractThis article summarizes the correlation procedures developed for IUPAC Project 2012-040-1-100 [Reference correlations for the thermal conductivity and viscosity of fluids over extended range of conditions (vapor, liquid and supercritical regions)]. This project is focused on the development of wide-range reference correlations for the thermal conductivity and viscosity of fluids that incorporate as much theoretical knowledge of these properties as possible. The thermal conductivity and viscosity correlations developed here for pure fluids are functions of temperature and density. The best available equations of state for a given fluid are used to calculate the thermodynamic properties required for these correlations, often from measured temperatures and pressures. The correlation methodology developed during this project has been applied to hexane in this report but can be applied to any pure fluid with a reliable equation of state and reliable data for the thermal conductivity and viscosity over a significant range of temperatures and densities.

Renormalization Group Theory Applied to the CPA Equation of State: Impacts on Phase Equilibrium and Derivative Properties

2019 ◽  
Author(s):  
Gabriel Silva ◽  
Charlles Abreu ◽  
Frederico W. Tavares
Keyword(s):  
Renormalization Group ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Chemical Engineering ◽  
Equations Of State ◽  
Thermodynamic Description ◽  
Critical Conditions ◽  
Liquid Equilibrium ◽  
Vapor Liquid Equilibrium ◽  
Vapor Liquid

Calculation of thermodynamic properties such as vapor-liquid phase behavior with equations of state is largely and successfully employed in chemical engineering applications.<br>However, in the proximities of the critical point, the different density-fluctuation scales inherent to critical phenomena introduce significant changes in these thermodynamic properties, with which the classical equations of state are not prepared to deal.<br>Aiming at correcting this failure, we apply a renormalization-group methodology to the CPA equation of state in order to improve the thermodynamic description in the vicinity of critical points.<br>We use this approach to compute vapor-liquid equilibrium of pure components and binary mixtures, as well as derivative properties such as speed of sound and heat capacity.<br>Our results show that this methodology is able to provide an equation of state with the correct non-classical behavior, thus bringing it in consonance with experimental observation of vapor-liquid equilibrium and derivative properties in near-critical conditions.

SITE-SPECIFIC EQUATIONS OF STATE FOR COASTAL SEA AREAS AND INLAND WATER BODIES

2017 ◽  
Author(s):  
Natalia Andrulionis ◽  
Natalia Andrulionis ◽  
Ivan Zavialov ◽  
Ivan Zavialov ◽  
Elena Kovaleva ◽  
...  
Keyword(s):  
Equation Of State ◽  
Black Sea ◽  
Water Samples ◽  
Equations Of State ◽  
Sea Water ◽  
Ionic Composition ◽  
Water Bodies ◽  
Aral Sea ◽  
The Black Sea ◽  
Coastal Sea

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water samples from the Aral Sea, the Black Sea and the Issyk-Kul Lake were performed using a high-precision laboratory density meter. The obtained results were compared with the density values calculated for the considered water samples by the EOS-80 equation. It was shown that difference in ionic composition between Standard Seawater and the considered water bodies results in significant inaccuracies in determination of water density using the EOS-80 equation. Basing on the laboratory measurements of density under various salinity and temperature values we constructed a new equation of state for the Aral Sea and the Black Sea water samples and estimated errors for their coefficients.

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