scholarly journals A thermodynamically consistent model of a liquid-vapor fluid with a gas

2019 ◽  
Vol 53 (1) ◽  
pp. 63-84 ◽  
Author(s):  
Hélène Mathis
Keyword(s):  
Phase Transition ◽  
Thermodynamical Equilibrium ◽  
Geometrical Properties ◽  
Consistent Model ◽  
Growth Criterion ◽  
Three Phase ◽  
Symmetric Constraint ◽  
Phase Mixture ◽  
Gibbs Formalism ◽  
Mass Volume

This work is devoted to the consistent modeling of a three-phase mixture of a gas, a liquid and its vapor. Since the gas and the vapor are miscible, the mixture is subjected to a non-symmetric constraint on the volume. Adopting the Gibbs formalism, the study of the extensive equilibrium entropy of the system allows to recover the Dalton’s law between the two gaseous phases. In addition, we distinguish whether phase transition occurs or not between the liquid and its vapor. The thermodynamical equilibria are described both in extensive and intensive variables. In the latter case, we focus on the geometrical properties of equilibrium entropy. The consistent characterization of the thermodynamics of the three-phase mixture is used to introduce two Homogeneous Equilibrium Models (HEM) depending on mass transfer is taking into account or not. Hyperbolicity is investigated while analyzing the entropy structure of the systems. Finally we propose two Homogeneous Relaxation Models (HRM) for the three-phase mixtures with and without phase transition. Supplementary equations on mass, volume and energy fractions are considered with appropriate source terms which model the relaxation towards the thermodynamical equilibrium, in agreement with entropy growth criterion.

scholarly journals Admissible equations of state for immiscible and miscible mixtures

2019 ◽  
Vol 66 ◽  
pp. 1-21 ◽  
Author(s):  
Gloria Faccanoni ◽  
Hélène Mathis
Keyword(s):  
General Framework ◽  
Equations Of State ◽  
Two Phase ◽  
Geometrical Properties ◽  
Homogeneous Equilibrium ◽  
Phase Mixture ◽  
Gibbs Formalism ◽  
Relaxation Models

This paper addresses the construction of admissible Equations of State (EoS) for compressible two-phase ows. We investigate two approaches. In the first one, the mixture is treated as a single uid with a complex thermodynamic. Most of the time the available EoS are determined experimentally and are often incomplete EoS, i.e. we know only the pressure as a function of the volume and the temperature. We present here a general framework to compute a complete EoS based on such an incomplete EoS. In the second approach, each phase is depicted by its own EoS. Following the Gibbs formalism, the mixture entropy is the sum of the phasic entropies which achieves its maximum at equilibrium. Depending on the miscibility of the mixture, one gets different geometrical properties on the resulting mixture entropy. Eventually we address the coupling of mixture EoS with the dynamic of the uid. Homogeneous Equilibrium and Relaxation Models (HEM and HRM) are introduced for an immiscible and a miscible two-phase mixture. Hyperbolicity is ensured taking advantage of the concavity properties of the mixture entropies.

A Three-Phase Constitutive Model for TiNiNb Shape Memory Alloys

2010 ◽  
Vol 97-101 ◽  
pp. 660-666
Author(s):  
Jun Wang ◽  
Zhi Ming Hao ◽  
Ping An Shi ◽  
Shao Rong Yu ◽  
Wei Fen Li
Keyword(s):  
Phase Transition ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Conventional Theory ◽  
Material Parameters ◽  
Three Phase ◽  
The Individual

A three-phase constitutive model for TiNiNb shape memory alloys (SMAs) is proposed based on the fact that TiNiNb SMAs are dynamically composed of austenite, martensite and -Nb phases. In the considered ranges of stress and temperature, the behaviors of austenite, martensite and -Nb phases are assumed to be elastoplastic, and the behavior of an SMA is regarded as the dynamic combination of the individual behavior of each phase. Then a macroscopic constitutive description for TiNiNb SMAs is obtained by the conventional theory of plasticity, the theory of mixture, the theory of inclusion, and the description of phase transition by Tanaka. The method for determination of the material parameters is given. This constitutive model can describe the main characteristics of SMAs, such as ferrcelasticity, pseudoelasticity and shape memory effect.

scholarly journals Non-linear dynamic response and vibration of an imperfect three-phase laminated nanocomposite cylindrical panel resting on elastic foundations in thermal environments

2017 ◽  
Vol 24 (6) ◽  
pp. 951-962 ◽  
Author(s):  
Pham Van Thu ◽  
Nguyen Dinh Duc
Keyword(s):  
Dynamic Response ◽  
Polymer Nanocomposite ◽  
Cylindrical Panel ◽  
Geometrical Properties ◽  
Elastic Foundations ◽  
Thermal Environments ◽  
Linear Dynamic ◽  
Geometrical Imperfection ◽  
Three Phase ◽  
Non Linear

AbstractThis paper presents an analytical approach to investigate the non-linear dynamic response and vibration of an imperfect three-phase laminated nanocomposite cylindrical panel resting on elastic foundations in thermal environments. Based on the classical laminated shell theory and stress function, taking into account geometrical non-linearity, initial geometrical imperfection, Pasternak-type elastic foundation, and temperature, the governing equations of the three-phase laminated nanocomposite cylindrical panel are derived. The numerical results for the dynamic response and vibration of the polymer nanocomposite cylindrical panel are obtained by using the Runge-Kutta method. The influences of fibres and nanoparticles, different fibre angles, material and geometrical properties, imperfection, elastic foundations, and temperature on the non-linear dynamic response of the polymer nanocomposite cylindrical panel are discussed in detail.

Properties of surfactant/oil/water emulsified systems in the neighborhood of the three-phase transition

1980 ◽  
Vol 77 (1) ◽  
pp. 288-289 ◽  
Author(s):  
Jean L Salager ◽  
Lirio Quintero ◽  
Ennodio Ramos ◽  
JoséM Anderez
Keyword(s):  
Phase Transition ◽  
Three Phase ◽  
Oil Water

scholarly journals Effects of Hadron-Quark Phase Transitions in Hybrid Stars within the NJL Model

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 425 ◽  
Author(s):  
Ignacio Ranea-Sandoval ◽  
Milva Orsaria ◽  
Germán Malfatti ◽  
Daniela Curin ◽  
Mauro Mariani ◽  
...  
Keyword(s):  
Phase Transition ◽  
Mean Field ◽  
Temperature Limit ◽  
Hadronic Matter ◽  
Transition Diagram ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Non Local ◽  
Gibbs Formalism ◽  
Hybrid Stars

We study local and non-local Polyakov Nambu-Jona-Lasinio models and analyze their respective phase transition diagram. We construct hybrid stars using the zero temperature limit of the local and non-local versions of Nambu-Jona-Lasinio model for quark matter and the modern GM1(L) parametrization of the non-linear relativistic mean field model for hadronic matter. We compare our models with data from PSR J1614-2230 and PSR J0343+0432 and also from GW170817 and its electromagnetic counterpart GRB170817A and AT2017gfo. We study observational signatures of the appearance of a mixed phase as a result of modeling a phase transition that mimics the Gibbs formalism and compare the results with the sharp first-order phase transition obtained using the Maxwell construction. We also study in detail the g-mode associated with discontinuities in the equation of state, and calculate non-radial oscillation modes using relativistic Cowling approximation.

scholarly journals Modeling Heat Transport in Systems of Hydrate-Filled Sediments Using Residual Thermodynamics and Classical Nucleation Theory

2021 ◽  
Vol 11 (9) ◽  
pp. 4124
Author(s):  
Mojdeh Zarifi ◽  
Bjørn Kvamme ◽  
Tatiana Kuznetsova
Keyword(s):  
Phase Transition ◽  
Mass Transport ◽  
Heat Transport ◽  
Film Growth ◽  
Growth Models ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Fundamental Properties ◽  
Consistent Model ◽  
Hydrate Phase

As in any other phase transition, hydrate phase transition kinetics involves an implicit coupling of phase transition thermodynamic control and the associated dynamics of mass and heat transport. This work provides a brief overview of certain selected hydrate film growth models with an emphasis on analyzing the hydrate phase transition dynamics. Our analysis is based on the fundamental properties of hydrate and hydrate/liquid water interfaces derived from molecular modeling. We demonstrate that hydrate phase transitions involving water-dominated phases are characterized by heat transport several orders of magnitude faster than mass transport, strongly suggesting that any hydrate phase transition kinetic models based on heat transport will be entirely incorrect as far as thermodynamics is concerned. We therefore propose that theoretical studies focusing on hydrate nucleation and growth should be based on concepts that incorporate all the relevant transport properties. We also illustrate this point using the example of a fairly simplistic kinetic model, that of classical nucleation theory (CNT), modified to incorporate new models for mass transport across water/hydrate interfaces. A novel and consistent model suitable for the calculation of enthalpies is also discussed and appropriate calculations for pure components and relevant mixtures of carbon dioxide, methane, and nitrogen are demonstrated. This residual thermodynamic model for hydrate is consistent with the free energy model for hydrate and ensures that our revised CNT model is thermodynamically harmonious.

scholarly journals О критической точке плавления простого вещества

2021 ◽  
Vol 63 (7) ◽  
pp. 966
Author(s):  
М.Н. Магомедов
Keyword(s):  
Phase Transition ◽  
Critical Point ◽  
Sharp Decrease ◽  
Amorphous Structure ◽  
State Equation ◽  
Phase Model ◽  
Subsequent Increase ◽  
Simple Matter ◽  
Three Phase ◽  
Temperature And Pressure

Based on the three-phase model of simple matter reviewed to the appearance and disappearance of the S-loop of a phase transition (PT) of the first kind on isotherme of state equation in the range of PT crystal-liquid (C-L). Calculations performed for argon showed that the S-loop of PT C-L on the isotherm of the state equation arises due to a sharp decrease and subsequent increase in pressure associated with the appearance of delocalized atoms at an isothermal increase in the specific volume. With an increase in temperature on the isotherm, the pressure associated with the delocalization of atoms passes from the negative region (where it compressed the system) to the positive region (where it stretches the system). This behavior of this function leads both to the appearance of the S-loop of the C-L PT on the isotherm of the equation of state, and to the disappearance of the S-loop of the C-L PT at high temperatures with the formation of the critical point of the C-L PT. The change in the parameters of the critical point of PT C-L with a decrease in the number of atoms in the nanosystem is studied. It is shown that during the transition to the nanosystem, the critical temperature and pressure decrease, and the critical molar volume increases. Calculations in the framework of the three-phase model of a simple matter showed that the structure at the critical point of PT C-L is close to an amorphous packing. At the same time, with a decrease in the number of atoms in the nanosystem, the parameters of this amorphous structure at the critical point of PT C-L change slightly.

scholarly journals Phase Transition and Optical Properties for Ultrathin KNbO3Nanowires

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Shulin Yang ◽  
Yongming Hu ◽  
Shengfu Wang ◽  
Haoshuang Gu ◽  
Yu Wang
Keyword(s):  
Phase Transition ◽  
Optical Properties ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Light Emission ◽  
Hydrothermal Route ◽  
Photoluminescence Study ◽  
Phase Structures ◽  
Three Phase ◽  
Visible Light Emission

Fascicular KNbO3nanowires with tetragonal perovskite structures and ultrasmall diameters are synthesized by hydrothermal route at about 150°C for 24 hours. The concentrations of medium alkalinity have influenced phase structures and the final morphologies of the products significantly by modifying the conditions in process. The as-prepared KNbO3nanowires exhibit three phase transitions at about 343, 454.7, and 623 K as the temperature increases from 250 to 700 K. The band gap is about 3.78 eV for KNbO3nanowires. Photoluminescence study at room temperature reveals two visible light emission bands peaking at ~551 and 597 nm, respectively, which may be due to the oxygen vacancies, site niobium (occupy the location of Nb), and antisite niobium (occupy the location of K) in KNbO3nanowires.

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