Prediction of the thermodynamic properties of {ammonia+water} using cubic equations of state with the SOF cohesion function

2011 ◽  
Vol 303 (1) ◽  
pp. 96-102 ◽  
Author(s):  
Freddy L. Figueira ◽  
Sylvana Derjani-Bayeh ◽  
Claudio Olivera-Fuentes
2011 ◽  
Vol 25 (10) ◽  
pp. 1393-1407 ◽  
Author(s):  
JING-HE WU ◽  
XIAN-LIN ZHAO ◽  
YOU-LIN SONG ◽  
GUO-DONG WU

The all-electron full-potential linearized muffin-tin orbital method, by means of quasi-harmonic Debye model, is applied to investigate the elastic constant and thermodynamic properties of body-centered-cubic tantalum (bcc Ta). The calculated elastic constants of bcc Ta at 0 K is consistent with the previous experimental and theoretical results. Our calculations give the correct trends for the pressure dependence of elastic constants. By using the convenient quasi-harmonic Debye model, we refined the thermal equations of state. The thermal expansivity and some other thermal properties agree well with the previous experimental and theoretical results.


1974 ◽  
Vol 27 (3) ◽  
pp. 647 ◽  
Author(s):  
DV Fenby ◽  
NF Pasco

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.


1974 ◽  
Vol 27 (10) ◽  
pp. 2159 ◽  
Author(s):  
NF Pasco ◽  
DV Fenby

Measurements are reported of the vapour pressures of the system carbon tetrachloride + hexafluorobenzene at 278.68 K. The molar excess Gibbs functions GE/M, obtained from these measurements have been combined with previously reported molar excess enthalpies to give GE/M at 298 K. Thermodynamic properties of CCl4+C6F6 at 298 K are compared with the predictions of liquid mixture theories based on analytic equations of state.


2015 ◽  
Vol 29 (13) ◽  
pp. 1550089 ◽  
Author(s):  
Minhui Shan ◽  
Jianxiang Tian

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.


1991 ◽  
Vol 61 (1) ◽  
pp. 902-908 ◽  
Author(s):  
Kh. S. Abdulkadirova ◽  
S. B. Kiselev ◽  
I. G. Kostyukova ◽  
L. V. Fedyunina

Author(s):  
Jesús M. García ◽  
Marco E. Sanjuan M. ◽  
Ricardo Vasquez Padilla

Finding optimal operating conditions of solar-based power and cooling systems is always a challenge. Performance of these systems is highly dependent on several important parameters, which not only impact the long-term efficiency but also its technical and economic feasibility. This paper studies the operation/configuration problem of an ammonia-water power and cooling cycle using an exergetic analysis. Thermodynamic performance of the combined cycle was addressed by using analysis of variance and multiple linear regression analysis. Modeling was done in Matlab®, using Refprop 9.0 to calculate the thermodynamic properties of the ammonia-water mixture. Convergence issues were observed on the thermodynamic properties estimation carried out by Refprop when the stream had high ammonia mass fraction. To solve this issue an averaging algorithm was implemented online to estimate such properties using pure ammonia data and high, but stable, ammonia concentration data. After this implementation, small differences between current and reference model were seen. Optimum operating conditions were obtained using response surface technique. The response variable used was the ratio between exergetic efficiency and exergy destruction. Results showed that the response variable is mainly influenced by the ammonia concentration, pressure ratio, turbine efficiency and temperature gradient in the heat exchanger. Finally integration of the power/cooling cycle with a solar field was performed using two types of concentrated solar collectors: Linear Fresnel Collector (LFC) and Parabolic Trough Collector (PTC). The analysis showed that LFC technology can be a viable alternative for small scale applications combined with power/cooling systems.


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