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Relations between timescales of stochastic thermodynamic observables J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230516
Erez Aghion, Jason R. GreenAny real physical process that produces entropy, dissipates energy as heat, or generates mechanical work must do so on a finite timescale. Recently derived thermodynamic speed limits place bounds on these observables using intrinsic timescales of the process. Here, we derive relationships for the thermodynamic speeds for any composite stochastic observable in terms of the timescales of its individual

Concepts of phenomenological irreversible quantum thermodynamics II: time dependent statistical ensembles of bipartite systems J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230426
Wolfgang MuschikThe widespread opinion is that original quantum mechanics is a reversible theory, but this statement is only true for undecomposed systems that are those systems for which subsystems are out of consideration. Taking subsystems into account, as it is by definition necessary for decomposed systems, the interaction Hamiltonians –which are absent in undecomposed systems– can be a source of irreversibility

Thermodynamic analysis of the effect of rotation on gas adsorption J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230411
Ramonna I. Kosheleva, Thodoris D. Karapantsios, Margaritis Kostoglou, Athanasios Ch. MitropoulosThis study examines the effect of a short term rotation on a system of constant volume. Adsorption of CO2 is performed on Activated Carbon (AC) at 281, 293 and 298 K with a special designed device that allows rotation. The adsorption isotherms were conducted up to 10 bar for both No Rotational (NoROT) and Rotational (ROT) cases. The ROT case refers to 60 s of rotation at 5000 rpm. The experimental

Oblique shock wave in turbulent flow J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230404
Andriy A. Avramenko, Andrii I. Tyrinov, Igor V. Shevchuk, Nataliya P. DmitrenkoThe main attention is paid to the analytical analysis of an oblique shock wave in a turbulent adiabatic gas flow. For this purpose, a modified Rankine–Hugoniot model was obtained. On its basis, a solution was derived for the Rankine–Hugoniot conditions for a gas flow with various degrees of turbulence, as well as the equation of the modified Hugoniot adiabat. The behavior of the velocity of an adiabatic

The entropy production paradox for fractional diffusion J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230317
Karl Heinz Hoffmann, Christopher Essex, Janett Prehl, Kathrin KulmusDispersive diffusion and wave propagation seem to be unconnected and fundamentally different evolution equations. In the context of anomalous diffusion however modeling approaches based on fractional diffusion equations have been presented, which allow to build a continuous bridge between the two regimes. The transition from irreversible dispersive diffusion to reversible wave propagation shows an

Multiscale theory J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230317
Miroslav GrmelaBoltzmann kinetic equation is put into the form of an abstract time evolution equation representing links connecting autonomous mesoscopic dynamical theories involving varying amount of details. In the chronological order we present results that led to the abstract time equation evolution in both state space and the space of vector fields. In the final section we list some open problems.

Generalized Onsager fluxes based on inexact differential 1form J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230306
Qiang Yang, Kuangdai Leng, Man Zhang, Yaoru LiuOnsager fluxes proposed by D.G.B. Edelen assume that the same symmetry, nonlinear Onsager reciprocal relations, holds near and far from equilibrium. This assumption leads to exact differential 1form J ⋅ dX everywhere, where J and X are thermodynamic fluxes and forces, respectively. However, thermodynamic fluxes far from equilibrium are characterized by symmetry breaking, which lead to the inexact

On small local equilibrium systems J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230301
Hans Christian ÖttingerEven for large nonequilibrium systems, local equilibrium subsystems in the presence of strong inhomogeneities may be very small. Such situations typically arise either in the presence of large gradients of temperature, velocity or pressure, or in transition zones between different phases. For small thermodynamic systems, the Euler equation of macroscopic thermodynamics does not hold. One less equation

A practical upperbound efficiency model for solar power plants J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230225
Eduardo GonzálezMora, Ram Poudel, María Dolores DuránGarcíaA generalized model for the maximum work rate extractable from the Sun is developed considering a reversible and an endoreversible system to define a more practical upperbound efficiency for the conversion of solar radiation into work and power. This model is based on a photothermal work extractor in communication with a hightemperature radiation reservoir and a lowtemperature heat sink. Following

Energy production in onequbit quantum Agrawal machines J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230124
Julio J. FernándezWe obtain the power and Ωfunction of onequbit Agrawal quantum heat engines solving the Lindbland equation and using the tools of Finite Time Thermodynamics. We prove that these two thermodynamic functions have their maximum values for efficiencies different to zero and the Carnot efficiency. Finally, analyzing the high temperature limit of AQHEs we discover the range of temperatures for which the

The optimization of heat transfer in thermally convective micropolarbased nanofluid flow by the influence of nanoparticle’s diameter and nanolayer via stretching sheet: sensitivity analysis approach J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230124
Liaqat Ali, Pardeep Kumar, Zahoor Iqbal, Sharifah E. Alhazmi, Sujesh Areekara, M. M. Alqarni, Alphonsa Mathew, Retna ApsariThe proposed study demonstrates the flow phenomenon and thermovariation of a magnetized stretching sheet inducedradiative nanofluid flow. By incorporating the response surface methodology, the heat transfer rate of the thermally convective flow of nanofluid is optimized. The graphene nanomaterial is used in the waterbased nanofluid. A dynamic magnetic field, thermal radiation, and the Cattaneo–Christov

A simplified analysis of the Feynman pallet and ratchet mechanism considering different forms of generated power J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230119
Delfino LadinoLuna, Juan C. ChimalEguía, Juan C. PachecoPaez, Ricardo T. PáezHernándezIn this paper, we analyze the advanced Feynman’s mechanism from the wellknown Feynman’s Lectures on Physics, under the maximum power output, maximum efficient power, and maximum power density criterion. Considering this mechanism like a thermal engine, and using a simplified model, the physical existence regions for these objective functions are shown. We also show their comparison for given values

Conservatively perturbed equilibrium in multiroute catalytic reactions J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230112
Vitaliy R. Trishch, Gregory S. Yablonsky, Denis Constales, Yuriy O. BeznosykThe phenomenon of conservatively perturbedequilibrium (CPE) in multiroute catalytic reactions was studied in the plugflow reactor (PFR). The following multiroute mechanisms were chosen for studying, i.e., the tworoute mechanism with the single common intermediate, the threeroute mechanism with some common steps, and the tworoute mechanism with the single common step and two common intermediates

Natural convection of a viscoelastic Cattaneo–Christov fluid bounded by thick walls with finite thermal conductivity J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230109
Luis Antonio DávalosOrozco, Jose Antonio Ruiz DíazThe linear natural convection of a Maxwell viscoelastic fluid with Cattaneo–Christov heat flux constitutive equation, between two thick walls with finite thermal conductivity is investigated. The viscoelastic fluid and the heat flux have different relaxation times. The main interest is on the curves of criticality for different thicknesses ratio D and thermal conductivities ratio X. In the middle range

The Onsager–Machlup theory of fluctuations and timedependent generalized normal distribution J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230106
Sergey I. SerdyukovGeneralization of the variational formulation of the Onsager–Machlup thermodynamic theory of fluctuation is considered. Within the framework of variational theory, we introduce the timedependent generalized normal distribution and Hamilton–Jacobi equation. The family of higherorder partial differential equations, which generalize classical Fokker–Planck equation, is considered. It is shown that proposed

Impact of wavy porous layer on the hydrodynamic forces and heat transfer of hybrid nanofluid flow in a channel with cavity under the effect of partial magnetic field J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20230106
Shafqat Hussain, Muhammad Amer Qureshi, Sameh E. AhmedThis computational analysis focuses on the effects of porous layer on the flow dynamics, heat transfer and hydrodynamic forces of hybrid nanofluid in a channel having an open cavity fixed with bottom wall in the presence of partial magnetic field. The set of PDEs governing the dynamics has been transformed to dimensionless form and simulated using higher order finite element method. In particular,

New formulation of the Navier–Stokes equations for liquid flows J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221216
Massimiliano Giona, Giuseppe Procopio, Alessandra Adrover, Roberto MauriFor isothermal liquid flows, the condition of incompressibility provides a useful simplification for describing their mechanical properties. Nevertheless, it overlooks acoustic effects, and it provides the unpleasant shortcoming of infinite propagation speed of velocity perturbations, no matter the type of constitutive equation for the shear stresses is adopted. In this paper, we provide a derivation

Are all chemical reactions in principle reversible? Thermodynamic distinction between “conceptually complete” and “practically complete” reactions J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221214
Andrea CiccioliAmong the chemical reactions having a pronounced thermodynamic driving force to the formation of products, a distinction has to be made between processes which attain a chemical equilibrium state very much shifted towards the products and those where the final equilibrium state corresponds to the truly complete consumption of reactant(s), i.e. where a true chemical equilibrium is actually not attained

Maximum ecological function performance for a threereservoir endoreversible chemical pump J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221207
Lingen Chen, Shuangshuang Shi, Huijun Feng, Yanlin GeEndoreversible chemical pump (ECP) is a theoretical model of electrochemical, photochemical, solidstate apparatus and mass exchangers. ECP can be classified as two, three and fourmassreservoir devices. The usual performance indicators for ECPs are energy pumping rate (EPR) and coefficient of performance (COP). Energybased ecological function objective (EFO) is introduced to performance optimization

Minimum power consumption of multistage irreversible Carnot heat pumps with heat transfer law of q ∝ (ΔT) m J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221206
Lingen Chen, Shaojun XiaFor the given initial finite hightemperature heat reservoir temperature, continuous Hamilton–Jacobi–Bellman equations are established to obtain optimal finite hightemperature heat reservoir temperature for minimum power consumption of multistage Carnot heat pumping system with generalized convective heat transfer law [q ∝ (ΔT) m ]. Analytical expression of optimal heat reservoir temperature with

Nonequilibrium thermodynamics modelling of the stressstrain relationship in soft twophase elasticviscoelastic materials J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221206
Pavlos S. Stephanou, Panayiotis Vafeas, Vlasis G. MavrantzasIn “soft–soft nanocomposites” based on film formation of latexes with structured particles, the combination of particle structure and interparticle crosslinking leads to materials that behave as nonlinear viscoelastic fluids at small strains and as highly elastic networks at larger strains. Similarly, in studies of flowinduced crystallization in polymers, a twophase model is often invoked in which

Nonlinear dynamics of blood passing through an overlapped stenotic artery with copper nanoparticles J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221206
Hanumesh Vaidya, Isaac Lare Animasaun, Kerehalli Vinayaka Prasad, Choudhari Rajashekhar, Javalkar U. Viharika, Qasem M. AlMdallalThe dynamics of blood carrying microscopic copper particles through overlapping stenotic arteries is an important research area needed for scrutinizing and exploring dynamics through blood vessels. Adipose tissue deposition and other elements of atherosclerosis generate the uncommon artery disease known as arterial stenosis. It limits blood flow and raises the risk of heart disease. Using the Casson

Densities and isothermal compressibilities from perturbed harddimerchain equation of state: application to nanofluids J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221202
Mahsa Taghizadehfard, Sayed Mostafa Hosseini, Mariano Pierantozzi, Mohammad Mehdi AlavianmehrDensities and isothermal compressibilities of several nanofluids were modelled using a perturbed hardchain equation of state (EoS) by an attractive term from Yukawa tail in 273–363 K range and pressure up to 45 MPa. The nanofluids of interest comprise TiO2Anatase (A), TiO2Rutile (R), SnO2, Co3O4, CuO, ZnO, and Al2O3 as nanoparticles dispersed in ethylene glycol, water, poly ethylene glycol, ethylene

Influence of drive chamber discharging process on nonlinear displacer dynamics and thermodynamic processes of a fluidicdriven GiffordMcMahon cryocooler J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221124
Debashis Panda, Manoj Kumar, Suraj K. Behera, Ashok K. Satapathy, Sunil Kr. SarangiContinuous effort is made on GiffordMcMahon cryocoolers (GMC) to amplify its refrigeration power, so they can be used to cool the cryopumps, high Tc magnets and development of efficient smallscale hydrogen liquefiers, etc. The fluidicdriven GMC is considered to be more reliable and prominent candidate than the mechanicallydriven GMC due to its structural simplicity and reliability. Nonetheless

Maximum work configuration of finite potential source endoreversible nonisothermal chemical engines J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20221118
Lingen Chen, Shaojun XiaChemical engine is an abstract model of some devices, such as solid state, photochemical, and electrochemical devices, photovoltaic cell, and mass exchangers. Finite chemicalpotential source is one of its features. Finite time thermodynamics provides effective theoretical tool for determining performance limits for given thermal systems, and determining optimal process paths of thermal systems for

Stability Analysis of Double Diffusive Convection in Local Thermal Nonequilibrium Porous Medium with Internal Heat Source and Reaction Effects J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220919
Najat J. Noon, Shatha A. HaddadThe internal heat source and reaction effects on the onset of thermosolutal convection in a local thermal nonequilibrium porous medium are examined, where the temperature of the fluid and the solid skeleton may differ. The linear instability and nonlinear stability theories of Darcy–Brinkman type with fixed boundary condition are carried out where the layer is heated and salted from below. The D 2

Heat Engine Cycle Configurations for Maximum Work Output with Generalized Models of Reservoir Thermal Capacity and Heat Resistance J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220915
Lingen Chen, Shaojun XiaA class of two finiteheatreservoir endoreversible heat engine with the generalized models of both the reservoir thermal capacities and heat resistances is investigated. The optimality condition for cycle maximum work output is derived by applying optimal control theory, and impacts of both thermal capacity characteristics of heat reservoirs and heat transfer laws on the optimal configurations are

A Study of the Nonlinear Thomson Effect Produced by Changing the Current in a Thermoelectric Cooler J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220915
Luis G. LafauriePonce, Farid Chejne, Luis M. RamirezAristeguieta, Carlos A. GomezThis work describes the nonlinear Thomson effect produced by a transient current source powering a thermoelectric cooler. The electric effect of the capacitive impedance in the semiconductors was considered in the equations as a novelty term that naturally appears by solving the Boltzmann equation to find the mathematical form of the current density. Thus, considering the new term and heath energy

Thermoelectric Response Characteristics of Bi2Te3 Based Semiconductor Materials J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220915
Zhanxuan Wang, Xiulian Cheng, Kai Guo, Enling Tang, Lei Li, Hui Peng, Yafei Han, Chuang Chen, Mengzhou Chang, Liping HeIn actual operation, the operating environment temperature of thermoelectric devices are constantly changing and rarely remain stable, and the electrical output characteristics of thermoelectric devices are largely determined by thermoelectric materials. In response to this question, the thermoelectric properties of thermoelectric materials (p and n type Bi 2 Te 3 {\mathrm{Bi}_{2}}{\mathrm{Te}_{3}}

Impact of Thermal Nonequilibrium on Flow Through a Rotating Disk with Power Law Index in Porous Media Occupied by OstwalddeWaele Nanofluid J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220914
E. Ragupathi, D. Prakash, M. Muthtamilselvan, Qasem M. AlMdallalThe current study is made to analyze the impact of local thermal nonequilibrium (LTNE) on the steady, incompressible, and viscous OstwalddeWaele nanoliquid over a rotating disk in a porous medium with the various power law index, due to many remarkable applications, such as aeronautical systems, rotating machineries, air cleaning machineries, electrical powergenerating systems, heat exchangers

Physical Mathematical Modeling and Simulation Based on Hyperbolic Heat Transfer for High Heating Rate Processes in Biomass Pyrolysis J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220909
Farid Chejne, Whady F. Florez, Juan C. Maya, Javier OrdonezLoza, Manuel GarciaPerezThis paper explores the hyperbolic heat transfer effects in processes involving high heating rates. The behavior of the model is analyzed in detail under different boundary conditions and the circumstances under which a nonFourier law could be used to describe thermal conduction processes established from physical mathematical analysis. Finally, the model developed here is coupled to a previous population

Exergetic and ExergoEconomical Analyses of a GasSteam Combined Cycle System J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220831
Guven Gonca, Bulent GuzelIn this study, the results of an investigation of the performance of a gassteam combined cycle system (GSCCS) under exergetic and exergoeconomical criteria are reported. The effective power (Pef), destroyed exergy (X), efficiency of exergy (ε), unit electric generation cost (Celec) and exergydependent economic worth of electrical energy (Cex,elec), which is novelly determined in this study, have

Optimal Configuration of Finite Source Heat Engine Cycle for Maximum Output Work with Complex Heat Transfer Law J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220719
Jun Li, Lingen ChenA finite source heat engine’s optimal configuration is studied. The model includes thermal resistance, heat leakage, a complex heat transfer law, and a heat source with variable temperature. The optimization objective is that the output work is the largest. The influences of factors such as the heat transfer law and heat leakage are analyzed. The results of this paper are universal and inclusive, and

Energy and Entropy in Open and Irreversible Chemical Reaction–Diffusion Systems with Asymptotic Stability J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220628
Aldo LedesmaDurán, Iván SantamaríaHolekThis work proposes a novel approach for the study of open systems described by completely irreversible reaction mechanisms in nonhomogeneous systems and subject to nonequilibrium boundary conditions. Using the nonequilibrium thermodynamics framework, we consider that in an autonomous system of reaction–diffusion equations, the thermodynamic potentials can be constructed from a Lyapunov function

Power Density Analysis and MultiObjective Optimization for an Irreversible Dual Cycle J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220429
Yanlin Ge, Shuangshuang Shi, Lingen Chen, Difeng Zhang, Huijun FengConsidering the various irreversibility conditions caused by heat transfer and working processes in a dual cycle, the power density performance is optimized by applying finitetime thermodynamics theory, and multiobjective optimization is performed by using NSGAII. The effects of cutoff ratio, maximum cycle temperature ratio, and various losses by heat transfer and working processes on the relationships

Thermodynamical Foundations of Closed Discrete NonEquilibrium Systems J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220404
Wolfgang MuschikSome tools of NonEquilibrium Thermodynamics of closed discrete systems are considered: the nonequilibrium state space, the nonequilibrium entropy as a state function and its connection with the entropy production, Clausius’ inequality, equilibrium and accompanying processes. Why can the thermostatic temperature be used successfully in thermal engineering even in cases of nonequilibrium?

Internal Variables as a Tool for Extending NavierStokes Equations J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220404
Arkadi BerezovskiThe formalism of the internal variable theory is applied to extend NavierStokes equations. The internal variable theory provides a thermodynamically consistent derivation of constitutive relations and equations of motion without a priori specifying the nature of internal variables. Both single and dual internal variables cases are thoroughly examined. The similarities and differences of the approaches

Nonlinear Thermal Transport with Inertia in Thin Wires: Thermal Fronts and Steady States J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220331
Michele Sciacca, David JouIn a series of papers we have obtained results for nonlinear heat transport when thin wires exchange heat nonlinearly with the surroundings, with particular attention to propagating solitons. Here we obtain and discuss new results related to the propagation of nonlinear heat fronts and some conceptual aspects referring to the application of the second principle of thermodynamics to some nonlinear

Thermotics As an Alternative Nonequilibrium Thermodynamic Approach Suitable for Real Thermoanalytical Measurements: A Short Review J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220331
Jaroslav Šesták, Robert ČernýThe general concept of temperature is thermodynamically defined in equilibrium somehow predictable even for nonequilibrium; however, it presents some still controversial aspects, as has been shown in a number of studies and reviews that have been published so far. Equilibrium concepts are often extrapolated to apply in microlocalized equilibrium and then appended to nonequilibrium in its entirety

Thermal Shear Waves Induced in Mesoscopic Liquids at Low Frequency Mechanical Deformation J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220331
Eni Kume, Laurence NoirezWe show that a confined viscous liquid emits a dynamic thermal response upon applying a low frequency (∼1 Hz) shear excitation. Hot and cold thermal waves are observed in situ at atmospheric pressure and room temperature, in a viscous liquid (polypropylene glycol) at various thicknesses ranging from 100 µm up to 340 µm, upon applying a mechanical oscillatory shear strain. The observed thermal effects

A Thermodynamical Description of Third Grade Fluid Mixtures J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220329
Matteo Gorgone, Patrizia RogolinoA complete thermodynamical analysis for a nonreacting binary mixture exhibiting the features of a third grade fluid is analyzed. The constitutive functions are allowed to depend on the mass density of the mixture and the concentration of one of the constituents, together with their first and second order gradients, on the specific internal energy of the mixture with its first order gradient, and on

Pattern Formation in Thermal Convective Systems: SpatioTemporal Thermal Statistics, Emergent Flux, and Local Equilibrium J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220323
Atanu Chatterjee, Takahiko Ban, Atsushi Onizuka, Germano IannacchioneWe discuss spatiotemporal pattern formation in two separate thermal convective systems. In the first system, hydrothermal waves (HTW) are modeled numerically in an annular channel. A temperature difference is imposed across the channel, which induces a surface tension gradient on the free surface of the fluid, leading to a surface flow towards the cold side. The flow pattern is axially symmetric along

Variational Approach to FluidStructure Interaction via GENERIC J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220210
Dirk Peschka, Andrea Zafferi, Luca Heltai, Marita ThomasWe present a framework to systematically derive variational formulations for fluidstructure interaction problems based on thermodynamical driving functionals and geometric structures in different coordinate systems by suitable transformations within this formulation. Our approach provides a promising basis to construct structurepreserving discretization strategies.

Optimizing the Piston Paths of Stirling Cycle Cryocoolers J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220208
Raphael Paul, Karl Heinz HoffmannThe ideal Stirling cycle provides a clear control strategy for the piston paths of ideal representations of Stirling cycle machines. For nonequilibrium Stirling cycle machines however, piston paths aiming to emulate the ideal cycle’s four strokes will not necessarily yield best performance. In this contribution, we ask the question: What are the COPoptimal piston paths for specific nonequilibrium

Effect of CrossSectional Geometry on Hydrothermal Behavior of Microchannel Heat Sink J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220208
Faraz Ahmad, Fawad Ahmed, Husan Ali, Zabdur Rehman, Muhammad Suleman, Izaz RaoufThe aim of this paper is to numerically analyze the hydrothermal behavior of different crosssectional geometries of microchannel heat sinks (MCHSs) and conduct a comparative analysis of traditional and nontraditional designs using ANSYS Fluent. It is expected that the proposed design discussed in this paper will improve the performance of MCHSs by maximizing the cooling capability and minimizing

Sources of Finite Speed Temperature Propagation J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220208
Paolo Maria Mariano, Marco SpadiniThe relation between heat flux and temperature gradient has been considered as a constitutive structure or as a balance law in different approaches. Both views may allow a description of heat conduction characterized by finite speed propagation of temperature disturbances. Such a result, which overcomes Fourier’s drawback of infinite speed propagation, can be obtained also by considering insufficient

NonLinear Stability and NonEquilibrium Thermodynamics—There and Back Again J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220207
Mark Dostalík, Vít PrůšaWe discuss the role of thermodynamics in nonlinear stability analysis of spatially distributed dissipative systems governed by nonlinear partial differential equations. We document profound interplay between various concepts in thermodynamics on one side and nonlinear stability analysis on the other side, and subsequently we summarize and comment on various results regarding the nonlinear stability

A Robust PhysicsBased Calculation of Evolving Gas–Liquid Interfaces J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220204
Lukáš Šatura, Mária Minichová, Michal Pavelka, Juraj Kosek, Alexandr ZubovDensity gradient theory describes the evolution of diffuse interfaces in both mixtures and pure substances by minimization of the total free energy, which consists of a nonconvex bulk part and an interfacial part. Minimization of the bulk free energy causes phase separation while building up the interfacial free energy (proportional to the square of gradients of the species’ densities) and it results

NonLinear Heat Transport Effects in Systems with Defects J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220202
David Jou, Liliana RestucciaIn this paper we explore several aspects of the influence of fixed and of mobile defects on the thermal conductivity of materials. In particular, we investigate the effects of the temperature and defect concentration dependence of the conductivity on phononic diodes and transistors and on the nonlinear thermal conductivity dependent on the heat flux in thermal superlattices.

Frontmatter J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Article Frontmatter was published on January 1, 2022 in the journal Journal of NonEquilibrium Thermodynamics (volume 47, issue 1).

Theoretical Analysis of Activation Energy Effect on Prandtl–Eyring Nanoliquid Flow Subject to Melting Condition J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Ikram Ullah, Rashid Ali, Hamid Nawab, Abdussatar, Iftikhar Uddin, Taseer Muhammad, Ilyas Khan, Kottakkaran Sooppy NisarThis study models the convective flow of Prandtl–Eyring nanomaterials driven by a stretched surface. The model incorporates the significant aspects of activation energy, Joule heating and chemical reaction. The thermal impulses of particles with melting condition is addressed. The system of equations is an ordinary differential equation (ODE) system and is tackled numerically by utilizing the Lobatto

Internal Structure and Heat Conduction in Rigid Solids: A TwoTemperature Approach J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Ruth Estephania GonzalezNarvaez, Mariano López de Haro, Federico VázquezA nonFourier thermal transport regime characterizes the heat conduction in solids with internal structure. Several thermodynamic theories attempt to explain the separation from the Fourier regime in such kind of systems. Here we develop a twotemperature model to describe the nonFourier regime from the principles of nonequilibrium thermodynamics. The basic assumption is the existence of two wellseparated

A Case Study of NonFourier Heat Conduction Using Internal Variables and GENERIC J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Mátyás Szücs, Michal Pavelka, Róbert Kovács, Tamás Fülöp, Péter Ván, Miroslav GrmelaApplying simultaneously the methodology of nonequilibrium thermodynamics with internal variables (NETIV) and the framework of General Equation for the NonEquilibrium Reversible–Irreversible Coupling (GENERIC), we demonstrate that, in heat conduction theories, entropy current multipliers can be interpreted as relaxed state variables. Fourier’s law and its various extensions—the Maxwell–Cattaneo–Vernotte

Significance of Entropy Generation and the Coriolis Force on the ThreeDimensional NonDarcy Flow of EthyleneGlycol Conveying Carbon Nanotubes (SWCNTs and MWCNTs) J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Ikram Ullah, Tasawar Hayat, Arsalan Aziz, Ahmed AlsaediNanofluids based on CNTs/ethylene glycol have a potential role in contributing to industrial applications like heat exchangers, domestic refrigerator, electronics cooling, etc. The aim and novelty of the present research is to communicate the significance of the Coriolis force and DarcyForchheimer stretched flow of ethylene glycol (EG) conveying carbon nanotubes (CNTs) in a rotating frame. Furthermore

Maximum Work Rate Extractable from Energy Fluxes J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Viorel BadescuA general formalism is developed to evaluate the amount of work extractable from energy fluxes. It covers nonequilibrium cases when the concept of exergy is not relevant. The rate of work deficiency, which has been previously introduced as the total loss of exergy, is defined here as the total loss of work, which would have resulted if all the work were lost to the environment. New performance indicators

Spectral Properties of Dissipation J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Peter Ván, Róbert Kovács, Federico VázquezThe novel concept of spectral diffusivity is introduced to analyze the dissipative properties of continua. The dissipative components of a linear system of evolution equations are separated into noninteracting parts. This separation is similar to mode analysis in wave propagation. The new modal quantities characterize dissipation and are best interpreted as effective diffusivities, or, in case of the

OverEquilibrium as a Result of ConservativelyPerturbed Equilibrium (Acyclic and Cyclic Mechanisms) J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Vitaliy R. Trishch, Yuriy O. Beznosyk, Denis Constales, Gregory S. YablonskyThe effect of overequilibrium, i. e., the effect at which the concentration of some substance is higher than the corresponding equilibrium value, is demonstrated for two types of ideal chemical reactors, continuously stirred tank reactor (CSTR) and plugflow reactor (PFR), respectively, under conditions of conservatively perturbedequilibrium (CPE). Two types of complex chemical mechanisms are analyzed

Transient, SubContinuum, Heat Conduction in Irregular Geometries J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20220101
Saad Bin Mansoor, Bekir S. YilbasPhonon transfer in irregular shapes is important for assessing the influence of shape effect on thermal transport characteristics of lowscale films. It becomes critical for evaluating the contribution of the scattering phonons to the phonon intensity distribution inside the film. Hence, the subcontinuum ballisticdiffusive model is incorporated to formulate the phonon transport in an irregular geometry

The Role of Internal Irreversibilities in the Performance and Stability of Power Plant Models Working at Maximum ϵEcological Function J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20210720
Gabriel ValenciaOrtega, Sergio LevarioMedina, Marco Antonio BarrancoJiménezThe proposal of models that account for the irreversibilities within the core engine has been the topic of interest to quantify the useful energy available during its conversion. In this work, we analyze the energetic optimization and stability (local and global) of three power plants, nuclear, combinedcycle, and simplecycle ones, by means of the Curzon–Ahlborn heat engine model which considers a

Size Effects and BeyondFourier Heat Conduction in RoomTemperature Experiments J. Non Equilib. Thermodyn. (IF 4.29) Pub Date : 20210716
Anna Fehér, Norbert Lukács, László Somlai, Tamás Fodor, Mátyás Szücs, Tamás Fülöp, Peter Ván, Róbert KovácsIt is a longlasting task to understand heat conduction phenomena beyond Fourier. Besides the lowtemperature experiments on extremely pure crystals, it has turned out recently that heterogeneous materials with macroscale size can also show thermal effects that cannot be modeled by the Fourier equation. This is called overdiffusive propagation, different from lowtemperature observations, and is