A. Avramenko, A. I. Tyrinov, I. V. Shevchuk, Nataliya P. Dmitrenko
Abstract The 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 turbulent gas flow during its passage through an oblique shock wave at different levels of turbulence is demonstrated. A modification of Prandtl’s law for the velocity coefficients was obtained. The shock polar was also analyzed. The relationship between the angular gas flow and the angle of the shock wave was derived. Finally, the condition for the appearance of an outgoing bow shock wave was obtained.
{"title":"Oblique shock wave in turbulent flow","authors":"A. Avramenko, A. I. Tyrinov, I. V. Shevchuk, Nataliya P. Dmitrenko","doi":"10.1515/jnet-2022-0093","DOIUrl":"https://doi.org/10.1515/jnet-2022-0093","url":null,"abstract":"Abstract The 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 turbulent gas flow during its passage through an oblique shock wave at different levels of turbulence is demonstrated. A modification of Prandtl’s law for the velocity coefficients was obtained. The shock polar was also analyzed. The relationship between the angular gas flow and the angle of the shock wave was derived. Finally, the condition for the appearance of an outgoing bow shock wave was obtained.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":" ","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46747360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Dispersive 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 unexpected increase in entropy production. This seemingly paradoxical behavior of fractional diffusion is reviewed and compared to the behavior of a tree-based diffusion model.
{"title":"The entropy production paradox for fractional diffusion","authors":"K. Hoffmann, C. Essex, J. Prehl, K. Kulmus","doi":"10.1515/jnet-2023-0020","DOIUrl":"https://doi.org/10.1515/jnet-2023-0020","url":null,"abstract":"Abstract Dispersive 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 unexpected increase in entropy production. This seemingly paradoxical behavior of fractional diffusion is reviewed and compared to the behavior of a tree-based diffusion model.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"137 - 148"},"PeriodicalIF":6.6,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42081460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Onsager 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 1-form 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 differential 1-form. It is shown in this paper that the inexact differential 1-form J ⋅ dX should be represented by multiple independent scalar-valued functions. Generalized Onsager fluxes are obtained based on such representation. Generalized Onsager fluxes do not satisfy the nonlinear Onsager reciprocal relations and contain multiple independent scalar-valued functions, so they are suitable to thermodynamic fluxes far from equilibrium. Generalized Onsager fluxes embody Onsager fluxes as a special case. Therefore, generalized Onsager fluxes provide a unified framework for thermodynamic fluxes near and far from equilibrium.
{"title":"Generalized Onsager fluxes based on inexact differential 1-form","authors":"Qiang Yang, K. Leng, Man Zhang, Yaoru Liu","doi":"10.1515/jnet-2022-0094","DOIUrl":"https://doi.org/10.1515/jnet-2022-0094","url":null,"abstract":"Abstract Onsager 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 1-form 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 differential 1-form. It is shown in this paper that the inexact differential 1-form J ⋅ dX should be represented by multiple independent scalar-valued functions. Generalized Onsager fluxes are obtained based on such representation. Generalized Onsager fluxes do not satisfy the nonlinear Onsager reciprocal relations and contain multiple independent scalar-valued functions, so they are suitable to thermodynamic fluxes far from equilibrium. Generalized Onsager fluxes embody Onsager fluxes as a special case. Therefore, generalized Onsager fluxes provide a unified framework for thermodynamic fluxes near and far from equilibrium.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"345 - 352"},"PeriodicalIF":6.6,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45060158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Even 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 implies one additional degree of freedom, which is the hallmark of small thermodynamic systems. I would like to offer some remarks on the description and role of small local equilibrium subsystems in nonequilibrium thermodynamics.
{"title":"On small local equilibrium systems","authors":"H. C. Öttinger","doi":"10.1515/jnet-2022-0074","DOIUrl":"https://doi.org/10.1515/jnet-2022-0074","url":null,"abstract":"Abstract Even 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 implies one additional degree of freedom, which is the hallmark of small thermodynamic systems. I would like to offer some remarks on the description and role of small local equilibrium subsystems in nonequilibrium thermodynamics.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"149 - 159"},"PeriodicalIF":6.6,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49628245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eduardo González-Mora, R. Poudel, M. D. Durán-García
Abstract A 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 upper-bound efficiency for the conversion of solar radiation into work and power. This model is based on a photo-thermal work extractor in communication with a high-temperature radiation reservoir and a low-temperature heat sink. Following the model, a parametric analysis of the concentration acceptance product (ξ) and thermal conductance is performed to identify the interdependence of variables for the solar exergy. The results are compared with existing models to provide a practical baseline of work and power extractable from concentrated solar power plants (CSP) technologies. Therefore, it is possible to quantify the irreversibilities of an idealized thermodynamic system operating between the Sun and the absorber (via radiative transfer) and the environment (via convective transfer).
{"title":"A practical upper-bound efficiency model for solar power plants","authors":"Eduardo González-Mora, R. Poudel, M. D. Durán-García","doi":"10.1515/jnet-2022-0080","DOIUrl":"https://doi.org/10.1515/jnet-2022-0080","url":null,"abstract":"Abstract A 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 upper-bound efficiency for the conversion of solar radiation into work and power. This model is based on a photo-thermal work extractor in communication with a high-temperature radiation reservoir and a low-temperature heat sink. Following the model, a parametric analysis of the concentration acceptance product (ξ) and thermal conductance is performed to identify the interdependence of variables for the solar exergy. The results are compared with existing models to provide a practical baseline of work and power extractable from concentrated solar power plants (CSP) technologies. Therefore, it is possible to quantify the irreversibilities of an idealized thermodynamic system operating between the Sun and the absorber (via radiative transfer) and the environment (via convective transfer).","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"331 - 344"},"PeriodicalIF":6.6,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43062486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Boltzmann 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.
{"title":"Multiscale theory","authors":"M. Grmela","doi":"10.1515/jnet-2022-0092","DOIUrl":"https://doi.org/10.1515/jnet-2022-0092","url":null,"abstract":"Abstract Boltzmann 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.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"121 - 135"},"PeriodicalIF":6.6,"publicationDate":"2023-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42962007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract We obtain the power and Ω-function of one-qubit 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 quantum behaviour is valid.
{"title":"Energy production in one-qubit quantum Agrawal machines","authors":"Julio J. Fernández","doi":"10.1515/jnet-2022-0081","DOIUrl":"https://doi.org/10.1515/jnet-2022-0081","url":null,"abstract":"Abstract We obtain the power and Ω-function of one-qubit 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 quantum behaviour is valid.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"303 - 312"},"PeriodicalIF":6.6,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44980489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Ali, Pardeep Kumar, Zahoor Iqbal, S. Alhazmi, S. Areekara, M. M. Alqarni, A. Mathew, R. Apsari
Abstract The proposed study demonstrates the flow phenomenon and thermo-variation of a magnetized stretching sheet induced-radiative 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 water-based nanofluid. A dynamic magnetic field, thermal radiation, and the Cattaneo–Christov heat flux model have used to represent the thermal behavior of the nanofluid. The simulation utilizes experimentally estimated values for the nanomaterial’s thermal conductivity and viscosity. To further reveal the thermal enhancement of the flow, the impact of nanoparticle diameter and the solid-liquid interfacial layer is proposed at the molecular level. The response surface methodology and the sensitivity analysis has used to examine the effects of the nanoparticle volume fraction, Biot number, and magnetic parameter on the rate of heat transfer statistically. A set of equations is formed from the governing partial differential equations by implementing suitable similarity transformations. The bvp4c approach is used to solve the problem numerically. The effect of various parameters has displayed through tables, graphs, and surface plots on heat transfer, mass transfer, and the local Nusselt number. It is discovered that as the Biot number increases, so does the concentration and temperature profile. An excellent accord between the present and previously existing solutions is establishing the validity of the achieved results.
{"title":"The optimization of heat transfer in thermally convective micropolar-based nanofluid flow by the influence of nanoparticle’s diameter and nanolayer via stretching sheet: sensitivity analysis approach","authors":"L. Ali, Pardeep Kumar, Zahoor Iqbal, S. Alhazmi, S. Areekara, M. M. Alqarni, A. Mathew, R. Apsari","doi":"10.1515/jnet-2022-0064","DOIUrl":"https://doi.org/10.1515/jnet-2022-0064","url":null,"abstract":"Abstract The proposed study demonstrates the flow phenomenon and thermo-variation of a magnetized stretching sheet induced-radiative 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 water-based nanofluid. A dynamic magnetic field, thermal radiation, and the Cattaneo–Christov heat flux model have used to represent the thermal behavior of the nanofluid. The simulation utilizes experimentally estimated values for the nanomaterial’s thermal conductivity and viscosity. To further reveal the thermal enhancement of the flow, the impact of nanoparticle diameter and the solid-liquid interfacial layer is proposed at the molecular level. The response surface methodology and the sensitivity analysis has used to examine the effects of the nanoparticle volume fraction, Biot number, and magnetic parameter on the rate of heat transfer statistically. A set of equations is formed from the governing partial differential equations by implementing suitable similarity transformations. The bvp4c approach is used to solve the problem numerically. The effect of various parameters has displayed through tables, graphs, and surface plots on heat transfer, mass transfer, and the local Nusselt number. It is discovered that as the Biot number increases, so does the concentration and temperature profile. An excellent accord between the present and previously existing solutions is establishing the validity of the achieved results.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"48 1","pages":"313 - 330"},"PeriodicalIF":6.6,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44069910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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