The purpose and scope of the International Journal of Thermodynamics is to provide a forum for the publication of original theoretical and applied work in the field of thermodynamics as it relates to systems, states, processes, and both non-equilibrium and equilibrium phenomena at all temporal and spatial scales. The journal, thus, provides a multidisciplinary and international platform for the dissemination to academia and industry of both scientific and engineering contributions, which touch upon a broad class of disciplines that are foundationally linked to thermodynamics and the methods and analyses derived there from. A common thread throughout is that of assessing how both the first and particularly the second laws of thermodynamics touch upon these disciplines.
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Vol 15, No 2: June 2012
Table of Contents
Regular Original Research Article
| Thermodynamic Properties of Liquids from Speed of Sound Measurements |
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Muhamed Bijedic |
61-68 |
A strategy for deriving thermodynamic properties of liquids (r, cp, cv) from speed of sound is presented. It is based on numerical integration of differential equations connecting speed of sound with other thermodynamic properties. Two different procedures are recommended: One for liquids with lower and moderate critical pressures (LMCP), and another for liquids with higher critical pressures (HCP). The set of differential equations is solved as the initial value problem in both cases. However, for LMCP liquids initial conditions (several accurate values of r and cp) are specified along isobar near the critical pressure, and for HCP liquids along the liquid-vapor saturation curve. The procedures are tested on ethane, carbon dioxide, and water. |
| Residual Thermodynamics: A Framework for Analysis of Non-Linear Irreversible Processes |
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Mattias Karl Gustavsson |
69-82 |
For a general irreversible process, incorporating sub-processes, entropy change may be expressed as the vector product of a thermodynamic force- and flow vector. A fundamental hypothesis is introduced, whereby a general irreversible process or sub-process may be categorized as being of a non-residual type, or of a residual type. A non-residual irreversible process is typically associated with continuous, linear behavior, where true material properties represent model constants, and the principle of local equilibrium is valid. A residual irreversible process is typically associated with discrete-, non-continuous-, and often non-linear behavior, where model constants do not represent generally accepted material properties. |
| Two-parameter Rankine Heat Pumps’ COP Equations |
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Adegboyega Olawale, Samuel Sunday Adefila |
83-90 |
Equations for ideal vapour compression heat pump coefficient of performance (COPR) which contain two fit-parameters are reported in this work. These equations contain either temperature term alone or temperature and pressure terms as the only thermodynamic variable(s). The best equation gave error ≥5% over wide range of temperature-lift and for different working fluid types that include fluorocarbons, hydrocarbons and inorganic fluids. In these respects the equation performs better than the one-parameter models reported earlier. |
| Comparative analysis of hydrate formation pressure applying cubic Equations of State (EoS), Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) |
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Mohammad Saber |
91-101 |
The objective of this work is making comparison between thermodynamic models and data-driven techniques accuracy in prediction of hydrate formation pressure as a function of temperature and composition of gas mixtures. The Peng-Rabinson (PR) and Patel-Teja (PT) equations of state are used for thermodynamic modeling and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS) are used as data-driven models. The capability of each method is evaluated by comparison with the experimental data collected from literature. It is shown that there is a good agreement between thermodynamic modeling and the experimental data in most of the cases; however, the prediction relative errors are more than 10% in some cases. The data-driven models are trained and tested using a set of experimental data and their optimum structures are selected based on the prediction error of the test data set. The accuracy of ANN for prediction of hydrate formation pressure is slightly better than those of PR and PT. The prediction errors of ANFIS for all cases are less than 1% which is very promising and proves the potential of ANFIS as a capable tool for prediction of the hydrate formation pressure. |
| Solubility prediction of some disperse Azo dyes in supercritical carbon dioxide using equation of states (EOSs) |
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Shahryar Jafari Nejad, Milad Asgarpour Khansary, Farshad Amiri |
103-110 |
The solubility of three disperse azo dyes, 4-(N,N-dimethylamino)-4’-itroazobenzene (D1), 4-(N,N-diethylamino)-4’-nitroazobenzene (D2) and Parared (D3) in supercritical carbon dioxide have been correlated with two equation of state. All critical properties have been estimated with a group contribution method (GCM). As far we know, solubility data for these dyes never has been correlated using an equation of state (EOS). Therefore, it is worthwhile to model the solubility of these disperse Azo dyes. In this work, the aim is correlating reported data with a new EOS and comparing obtained results with the results of Peng-Robinson EOS (PR-EOS) together with two adjustable parameter van der Waals mixing and combining rules. The calculated results showed that new EOS is more accurate than PR-EOS. It can be employed to speed up the process of SCF applications in industry. |
| Thermodynamical Study of Alcoholic Solutions of Poly (ethylene glycol) Diacrylate and Poly (ethylene glycol) Dimethacrylate |
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Maimoona Yasmin, Manisha Gupta |
111-117 |
With the aim to study the behaviour of polymer solutions, density and ultrasonic velocity of binary mixtures of pentanol with polyethylene glycol diacrylate and polyethylene glycol dimethacrylate have been investigated at 293.15 K, 303.15 K and 313.15 K, under atmospheric pressure. Thermophysical parameters viz. intermolecular free length, internal pressure and pseudo-Grüneisen parameter have been calculated which infer about the interactions and structural changes on mixing pentanol with these polymers. Enthalpy, entropy and Gibbs free energy of activation for viscous flow at different concentrations of polymer solution have been reported. Excess molar volume, deviation in isentropic compressibility, deviation in ultrasonic velocity, excess acoustic impedance and excess molar enthalpy have been calculated and results have been correlated with Redlich-Kister polynomial equation. Density and ultrasonic velocity data have been fitted by third order polynomial equation. |
| Exergoeconomic optimization of an Organic Rankine Cycle for low-temperature geothermal heat sources |
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Florian Heberle, Pascal Bassermann, Markus Preißinger, Dieter Brüggemann |
119-126 |
An exergoeconomic analysis of a geothermal power generation for a low-temperature resource is performed. An Organic Rankine Cycle (ORC) with isobutane and isopentane as working fluids is considered as binary power plant. A systematic parameter variation is done for the minimum temperature difference in the evaporator and condenser. The most suitable design parameters are evaluated under exergetic, economic and exergoeconomic criteria. The specific costs of electricity generation are minimal for the use of isobutane as working fluid and minimal temperature difference of 3 K at evaporation and 7 K at condensation. The most suitable concept for isopentane leads to only 0.4 % higher specific costs although the second law efficiency is 4.75 % lower. The exergoeconomic analysis permits to consider important criteria, like design and operating parameters in the fluid selection for ORC applications. |
ISSN: 2146-1511
