In this study, we investigate the linear transport of neutral system within the framework of relativistic kinetic theory. Under the relaxation time approximation, we obtain an iterative solution to the relativistic Boltzmann equation in generic stationary spacetime. This solution provides a scheme to study non-equilibrium system order by order. Our calculations are performed in generic hydrodynamic frame, and the results can be reduced to a specific hydrodynamic frame by imposing constraints. As a specific example, we analytically calculated the covariant expressions of the particle flow and the energy momentum tensor up to the first order in relaxation time. Finally and most importantly, we present all 14 kinetic coefficients for a neutral system, which are verified to satisfy the Onsager reciprocal relation in a generic hydrodynamic frame and guarantee a non-negative entropy production in the frame where the first order conservation laws are restored.
{"title":"A general relativistic kinetic theory approach to linear transport in generic hydrodynamic frame","authors":"Long Cui, Xin Hao, Liu Zhao","doi":"10.1515/jnet-2024-0024","DOIUrl":"https://doi.org/10.1515/jnet-2024-0024","url":null,"abstract":"In this study, we investigate the linear transport of neutral system within the framework of relativistic kinetic theory. Under the relaxation time approximation, we obtain an iterative solution to the relativistic Boltzmann equation in generic stationary spacetime. This solution provides a scheme to study non-equilibrium system order by order. Our calculations are performed in generic hydrodynamic frame, and the results can be reduced to a specific hydrodynamic frame by imposing constraints. As a specific example, we analytically calculated the covariant expressions of the particle flow and the energy momentum tensor up to the first order in relaxation time. Finally and most importantly, we present all 14 kinetic coefficients for a neutral system, which are verified to satisfy the Onsager reciprocal relation in a generic hydrodynamic frame and guarantee a non-negative entropy production in the frame where the first order conservation laws are restored.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"32 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805867","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}
G. Praveen Kumar Yadav, Pullarao Muvvala, R. Meenakshi Reddy
The increase of fossil fuel powered industrial processes and vehicles has resulted in the exhaustion of petroleum reserves and pollution of the environment. Because of its clean-burning, renewable, and biodegradable qualities, biodiesel is becoming more and more recognized as a potential diesel fuel alternative. The present study investigates engine performance and emission characteristics of cottonseed oil (CSBD20) and diesel blends tested on single-cylinder compression ignition engine by several injection timings, injection pressures, and ethanol shares. Performance parameters such as brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), exhaust emissions such as hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), carbon dioxide (CO2), and smoke were considered as output factors, considering injection timing (IT), ethanol share (ES), injection pressure (IP) as input factors utilizing artificial neural network (ANN) and taguchi grey relation analysis (GRA). The ANN model accurately predicts the input-output relationships of ethanol and cottonseed biodiesel blends, as validated by experimental comparisons. The predicted values for BTE, BSFC, HC, CO, NOx, and smoke show close alignment with experimental results, with marginal errors of 6.2 %, 2.8 %, 7.1 %, 4.7 %, 6.8 %, and 5.6 %, respectively, confirming its reliability. In addition, this study utilized Taguchi grey relational analysis (GRA) to find optimum engine operating conditions. The analysis revealed that the optimal engine operating conditions were IT at 27° CA bTDC, ES at 15 %, and IP at 200 bar. Furthermore, confirmation tests are also conducted at optimum operating conditions, and the revealed values are closer to taguchi GRA experiments and ANN predicted values.
{"title":"Optimization of injection parameters, and ethanol shares for cottonseed biodiesel fuel in diesel engine utilizing artificial neural network (ANN) and taguchi grey relation analysis (GRA)","authors":"G. Praveen Kumar Yadav, Pullarao Muvvala, R. Meenakshi Reddy","doi":"10.1515/jnet-2024-0095","DOIUrl":"https://doi.org/10.1515/jnet-2024-0095","url":null,"abstract":"The increase of fossil fuel powered industrial processes and vehicles has resulted in the exhaustion of petroleum reserves and pollution of the environment. Because of its clean-burning, renewable, and biodegradable qualities, biodiesel is becoming more and more recognized as a potential diesel fuel alternative. The present study investigates engine performance and emission characteristics of cottonseed oil (CSBD20) and diesel blends tested on single-cylinder compression ignition engine by several injection timings, injection pressures, and ethanol shares. Performance parameters such as brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), exhaust emissions such as hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO<jats:sub> <jats:italic>x</jats:italic> </jats:sub>), carbon dioxide (CO<jats:sub>2</jats:sub>), and smoke were considered as output factors, considering injection timing (IT), ethanol share (ES), injection pressure (IP) as input factors utilizing artificial neural network (ANN) and taguchi grey relation analysis (GRA). The ANN model accurately predicts the input-output relationships of ethanol and cottonseed biodiesel blends, as validated by experimental comparisons. The predicted values for BTE, BSFC, HC, CO, NO<jats:sub> <jats:italic>x</jats:italic> </jats:sub>, and smoke show close alignment with experimental results, with marginal errors of 6.2 %, 2.8 %, 7.1 %, 4.7 %, 6.8 %, and 5.6 %, respectively, confirming its reliability. In addition, this study utilized Taguchi grey relational analysis (GRA) to find optimum engine operating conditions. The analysis revealed that the optimal engine operating conditions were IT at 27° CA bTDC, ES at 15 %, and IP at 200 bar. Furthermore, confirmation tests are also conducted at optimum operating conditions, and the revealed values are closer to taguchi GRA experiments and ANN predicted values.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"183 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618335","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}
Xunyan Yin, Congzheng Li, Zhihai Kou, Ran Zhang, Hailun Zhou
Here, we investigate the effect of depositional nanoparticles (DNPs) on boiling heat transfer using molecular dynamics simulations. We discuss the type and density of DNPs and reveal their physical mechanism on boiling heat transfer. In the case of nanoparticle material changes, the onset time of explosive boiling, the heat flux, and the enhancement factor of the DNPs are calculated, and the results show that the heat transfer at the solid–liquid interface is enhanced due to the DNPs. The enhancement of Cu-DNP is the largest, followed by Ag- and Au-DNP. Compared with a smooth surface, the interfacial interaction of the DNP surface is increased, resulting in the improvement of the surface wettability, which is beneficial to heat transfer. Furthermore, the interfacial thermal resistance affects the heat transfer when the DNP material changes. The DNPs enhance the vibrational thermal matching of atoms at the solid–liquid interface, leading to heat traveling more easily across the interface, and thus the heat transfer between surface and fluid is enhanced. In the case of nanoparticle density changes, the results demonstrate that the boiling heat transfer is enhanced by an increase in DNP density, which confirms that the interfacial interaction and the thermal resistance have significant effects on the heat transfer at the solid–liquid interface.
{"title":"Effect of depositional nanoparticles on heat transfer at the solid–liquid interface using molecular dynamics simulations","authors":"Xunyan Yin, Congzheng Li, Zhihai Kou, Ran Zhang, Hailun Zhou","doi":"10.1515/jnet-2024-0080","DOIUrl":"https://doi.org/10.1515/jnet-2024-0080","url":null,"abstract":"Here, we investigate the effect of depositional nanoparticles (DNPs) on boiling heat transfer using molecular dynamics simulations. We discuss the type and density of DNPs and reveal their physical mechanism on boiling heat transfer. In the case of nanoparticle material changes, the onset time of explosive boiling, the heat flux, and the enhancement factor of the DNPs are calculated, and the results show that the heat transfer at the solid–liquid interface is enhanced due to the DNPs. The enhancement of Cu-DNP is the largest, followed by Ag- and Au-DNP. Compared with a smooth surface, the interfacial interaction of the DNP surface is increased, resulting in the improvement of the surface wettability, which is beneficial to heat transfer. Furthermore, the interfacial thermal resistance affects the heat transfer when the DNP material changes. The DNPs enhance the vibrational thermal matching of atoms at the solid–liquid interface, leading to heat traveling more easily across the interface, and thus the heat transfer between surface and fluid is enhanced. In the case of nanoparticle density changes, the results demonstrate that the boiling heat transfer is enhanced by an increase in DNP density, which confirms that the interfacial interaction and the thermal resistance have significant effects on the heat transfer at the solid–liquid interface.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"17 2 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599508","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}
Based on the definition of exergy-based efficient ecological-function (EEF) proposed in the existing literature, which is the product of energy conversion coefficient-of-performance (ɛ) and exergy-based ecological-function (E), this paper will introduce the exergy-based EEF into performance optimization for Carnot refrigerator cycle. Via endoreversible Carnot refrigerator model established in previous literature, expression of the exergy-based EEF of refrigerator is derived based on finite-time thermodynamic theory, relationships of dimensionless exergy-based EEF versus ɛ and cooling load (R) are studied, and performance differences of refrigerator cycles at the maximum exergy-based EEF, at the maximum E, and at the maximum efficient cooling-load conditions are compared. The results demonstrate that relationships of dimensionless exergy-based EEF versus R and ɛ are parabolic-like ones; in actual design, the refrigerator should be designed at the larger R and ɛ points. When exergy-based EEF is taken as optimization-objective, although R decreases slightly, ɛ is increased, and entropy-generation-rate (σ) is greatly decreased, so exergy-based EEF does not only reflect the compromise between the R and σ, but also reflect the compromise between the R and ɛ.
{"title":"Exergy-based efficient ecological-function optimization for endoreversible Carnot refrigerators","authors":"Yanju He, Yanlin Ge, Lingen Chen, Huijun Feng","doi":"10.1515/jnet-2024-0099","DOIUrl":"https://doi.org/10.1515/jnet-2024-0099","url":null,"abstract":"Based on the definition of exergy-based efficient ecological-function (EEF) proposed in the existing literature, which is the product of energy conversion coefficient-of-performance (<jats:italic>ɛ</jats:italic>) and exergy-based ecological-function (<jats:italic>E</jats:italic>), this paper will introduce the exergy-based EEF into performance optimization for Carnot refrigerator cycle. Via endoreversible Carnot refrigerator model established in previous literature, expression of the exergy-based EEF of refrigerator is derived based on finite-time thermodynamic theory, relationships of dimensionless exergy-based EEF versus <jats:italic>ɛ</jats:italic> and cooling load (<jats:italic>R</jats:italic>) are studied, and performance differences of refrigerator cycles at the maximum exergy-based EEF, at the maximum <jats:italic>E</jats:italic>, and at the maximum efficient cooling-load conditions are compared. The results demonstrate that relationships of dimensionless exergy-based EEF versus <jats:italic>R</jats:italic> and <jats:italic>ɛ</jats:italic> are parabolic-like ones; in actual design, the refrigerator should be designed at the larger <jats:italic>R</jats:italic> and <jats:italic>ɛ</jats:italic> points. When exergy-based EEF is taken as optimization-objective, although <jats:italic>R</jats:italic> decreases slightly, <jats:italic>ɛ</jats:italic> is increased, and entropy-generation-rate (<jats:italic>σ</jats:italic>) is greatly decreased, so exergy-based EEF does not only reflect the compromise between the <jats:italic>R</jats:italic> and <jats:italic>σ</jats:italic>, but also reflect the compromise between the <jats:italic>R</jats:italic> and <jats:italic>ɛ</jats:italic>.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"21 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599507","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}
In this paper, we perform an energetic analysis of a non-isothermal linear energy converter operated in inverse mode (refrigerator and heat pump). This is done within the framework of linear irreversible thermodynamics (LIT), starting from the model of an inverse linear energy converter (I-LEC) proposed by S. Gonzalez et al. (S. Gonzalez-Hernandez and L.-A. Arias-Hernandez, “Thermoelectric thomson relations revisited for a linear energy converter,” J. Non-Equilibrium Thermodyn., vol. 44, no. 3, pp. 315–332, 2019). We extend this model to the case of heat pumps, considering different objective functions and performing their respective analyses. We particularly focus on the coefficient of performance (COP) of heating, ϵH. Additionally, we propose other energetic functions that may be of interest in the analysis of heat pumps, drawing analogies with the well-known functions for refrigerators and heat engines. Finally, we present a brief description of thermoelectric phenomena, focusing primarily on the Peltier effect. A brief analysis of the results obtained in the context of thermoelectric cooling and heating is presented for a non-isothermal LEC.
在本文中，我们进行了一个非等温线性能量转换器在逆模式（冰箱和热泵）运行的能量分析。这是在线性不可逆热力学（LIT）的框架内完成的，从S. Gonzalez等人（S. Gonzalez- hernandez和l. a . a .）提出的逆线性能量转换器（I-LEC）模型开始。Arias-Hernandez，“对线性能量转换器的热电汤姆逊关系的重新审视”，J.非平衡热力学。，第44卷，no。3, pp. 315-332, 2019)。我们将此模型扩展到热泵的情况下，考虑不同的目标函数并执行各自的分析。我们特别关注供暖的性能系数（COP）， ε H。此外，我们提出了其他可能对热泵分析感兴趣的能量函数，与众所周知的冰箱和热机的功能进行类比。最后，我们简要描述了热电现象，主要集中在珀尔帖效应上。简要分析了非等温LEC在热电冷却和加热的情况下获得的结果。
{"title":"Energetic analysis of a non-isothermal linear energy converter operated in reverse mode (I-LEC): heat pump","authors":"Saul Gonzalez-Hernandez","doi":"10.1515/jnet-2024-0065","DOIUrl":"https://doi.org/10.1515/jnet-2024-0065","url":null,"abstract":"In this paper, we perform an energetic analysis of a non-isothermal linear energy converter operated in inverse mode (refrigerator and heat pump). This is done within the framework of linear irreversible thermodynamics (LIT), starting from the model of an inverse linear energy converter (I-LEC) proposed by S. Gonzalez et al. (S. Gonzalez-Hernandez and L.-A. Arias-Hernandez, “Thermoelectric thomson relations revisited for a linear energy converter,” <jats:italic>J. Non-Equilibrium Thermodyn.</jats:italic>, vol. 44, no. 3, pp. 315–332, 2019). We extend this model to the case of heat pumps, considering different objective functions and performing their respective analyses. We particularly focus on the coefficient of performance (COP) of heating, <jats:italic>ϵ</jats:italic> <jats:sub> <jats:italic>H</jats:italic> </jats:sub>. Additionally, we propose other energetic functions that may be of interest in the analysis of heat pumps, drawing analogies with the well-known functions for refrigerators and heat engines. Finally, we present a brief description of thermoelectric phenomena, focusing primarily on the Peltier effect. A brief analysis of the results obtained in the context of thermoelectric cooling and heating is presented for a non-isothermal LEC.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"212 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570377","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}
Carmelo F. Munafó, Patrizia Rogolino, Antonio Sellitto
In this paper we deepen into the influence of the boundary conditions on the heat-flux behavior in the case of thin nanowires. We compare the evolution of an initially inhomogeneous heat flux between two systems at the same (constant) temperature according to two theoretical models, one only emphasizing the role played by the non-local effects, and the other only accounting for the influence of the non-linear effects. It is found that non-local effects yield a monotonic trend toward the equilibrium, whereas non-linear effects yield an oscillating trend. The behavior of the entropy in both cases is analyzed as well.
{"title":"Heat transfer at nano-scale and boundary conditions: a comparison between the Guyer-Krumhansl model and the Thermomass theory","authors":"Carmelo F. Munafó, Patrizia Rogolino, Antonio Sellitto","doi":"10.1515/jnet-2024-0098","DOIUrl":"https://doi.org/10.1515/jnet-2024-0098","url":null,"abstract":"In this paper we deepen into the influence of the boundary conditions on the heat-flux behavior in the case of thin nanowires. We compare the evolution of an initially inhomogeneous heat flux between two systems at the same (constant) temperature according to two theoretical models, one only emphasizing the role played by the non-local effects, and the other only accounting for the influence of the non-linear effects. It is found that non-local effects yield a monotonic trend toward the equilibrium, whereas non-linear effects yield an oscillating trend. The behavior of the entropy in both cases is analyzed as well.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"33 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570368","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}
This investigation aimed to predict the temperature distribution in the inlet and exhaust valve and isotherms to the cooling media at a given load of a diesel engine. For the analysis that has been done a Tata- Mercedes diesel engine with 90 mm bore diameter and Stroke length of 120 mm was analysed using FEM through Ansys workbench 15.0. Steady as well as transient cases were considered in combination. The temperature distribution and isotherms are computed and plotted using Ansys. The results obtained by Ansys workbench 15.0 were satisfactory and were in line when compared with finite differential analysis. There is a large temperature variation along the length of the valve. It may vary from 560 °C to 110 °C from tip to valve head in the exhaust valve while this variation is less in the case of inlet valve from 540 °C to 100 °C from the face to the tip. The linear temperature difference between the nodes at the base of the stem to the node at the center of the face increases with time and acquires the maximum value of about 120 °C at about 10 s then it decreases till the valve attains a steady state value. Thus, was observed from analysis that during this time there is a maximum probability of failure of valves due to linear differences in temperature.
{"title":"Thermodynamic characterization of transient valve temperatures in diesel engines using probabilistic methods","authors":"Pardeep Kumar, Anikate Gupta, Dinesh Kumar, Vipin Kumar Sharma, Santosh Kumar Rai","doi":"10.1515/jnet-2024-0052","DOIUrl":"https://doi.org/10.1515/jnet-2024-0052","url":null,"abstract":"This investigation aimed to predict the temperature distribution in the inlet and exhaust valve and isotherms to the cooling media at a given load of a diesel engine. For the analysis that has been done a Tata- Mercedes diesel engine with 90 mm bore diameter and Stroke length of 120 mm was analysed using FEM through Ansys workbench 15.0. Steady as well as transient cases were considered in combination. The temperature distribution and isotherms are computed and plotted using Ansys. The results obtained by Ansys workbench 15.0 were satisfactory and were in line when compared with finite differential analysis. There is a large temperature variation along the length of the valve. It may vary from 560 °C to 110 °C from tip to valve head in the exhaust valve while this variation is less in the case of inlet valve from 540 °C to 100 °C from the face to the tip. The linear temperature difference between the nodes at the base of the stem to the node at the center of the face increases with time and acquires the maximum value of about 120 °C at about 10 s then it decreases till the valve attains a steady state value. Thus, was observed from analysis that during this time there is a maximum probability of failure of valves due to linear differences in temperature.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"85 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517942","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}
In general, the most important method of energy storage at the power plant scale is the pumped hydro method, which has been developed in two main models to improve its performance, which is pumped hydro combined with compressed gas (PHCCG) and pumped hydro in closed towers (PHWT). In this research, to answer which of these methods is more suitable, in the form of a case study, both systems were designed to store the generated energy in the Aghkand wind farm with a nominal power of 50 (MW), and the performance of both was completely compared with each other. The findings indicated that the efficiency of the PHWT method was higher, but on the other hand, the water requirement of the PHCCG method was much lower than the PHWT method. Also, in an innovative way, the PHWT system was presented with a combination of towers of different classes and the performance of each was investigated. Finally, by combining both PHWT and PHCCG systems, a new hybrid system (HPHWTCG) was proposed. By using this hybrid system, the advantages of both methods can be used at the same time and the disadvantages of each method can be eliminated to a great extent. The efficiency of PHWT and PHCCG is 65 % and 45 % respectively. The efficiency of HPHWTCG is between these two values based on its structure.
{"title":"Performance comparison of water towers and combined pumped hydro and compressed gas system and proposing a novel hybrid system to energy storage with a case study of a 50 MW wind farm","authors":"Amin Hadidi","doi":"10.1515/jnet-2024-0102","DOIUrl":"https://doi.org/10.1515/jnet-2024-0102","url":null,"abstract":"In general, the most important method of energy storage at the power plant scale is the pumped hydro method, which has been developed in two main models to improve its performance, which is pumped hydro combined with compressed gas (PHCCG) and pumped hydro in closed towers (PHWT). In this research, to answer which of these methods is more suitable, in the form of a case study, both systems were designed to store the generated energy in the Aghkand wind farm with a nominal power of 50 (MW), and the performance of both was completely compared with each other. The findings indicated that the efficiency of the PHWT method was higher, but on the other hand, the water requirement of the PHCCG method was much lower than the PHWT method. Also, in an innovative way, the PHWT system was presented with a combination of towers of different classes and the performance of each was investigated. Finally, by combining both PHWT and PHCCG systems, a new hybrid system (HPHWTCG) was proposed. By using this hybrid system, the advantages of both methods can be used at the same time and the disadvantages of each method can be eliminated to a great extent. The efficiency of PHWT and PHCCG is 65 % and 45 % respectively. The efficiency of HPHWTCG is between these two values based on its structure.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"23 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517943","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}
Ana Laura García-Perciante, Alma Rosa Méndez, Olivier Sarbach
The conditions for the existence of the Chapman–Enskog first-order solution to the Boltzmann equation for a dilute gas are examined from two points of view. The traditional procedure is contrasted with a somehow more formal approach based on the properties of the linearized collision operator. It is shown that both methods lead to the same integral equation in the non-relativistic scenario. Meanwhile, for relativistic systems, the source term in the integral equation adopts two different forms. However, as we explain, this does not lead to an inconsistency. In fact, the constitutive equations that are obtained from both methods are shown to be equivalent within relativistic first-order theories. The importance of stating invariant definitions for the transport coefficients in this context is emphasized.
{"title":"Existence of the Chapman–Enskog solution and its relation with first-order dissipative fluid theories","authors":"Ana Laura García-Perciante, Alma Rosa Méndez, Olivier Sarbach","doi":"10.1515/jnet-2024-0086","DOIUrl":"https://doi.org/10.1515/jnet-2024-0086","url":null,"abstract":"The conditions for the existence of the Chapman–Enskog first-order solution to the Boltzmann equation for a dilute gas are examined from two points of view. The traditional procedure is contrasted with a somehow more formal approach based on the properties of the linearized collision operator. It is shown that both methods lead to the same integral equation in the non-relativistic scenario. Meanwhile, for relativistic systems, the source term in the integral equation adopts two different forms. However, as we explain, this does not lead to an inconsistency. In fact, the constitutive equations that are obtained from both methods are shown to be equivalent within relativistic first-order theories. The importance of stating invariant definitions for the transport coefficients in this context is emphasized.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"34 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517941","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}
Fernando Bautista, Juan Paulo García-Sandoval, Octavio Manero
Phase diagrams out of equilibrium have been the subject of intense research. An essential concept in these diagrams is the phase definition. Currently, that definition is well established for systems at classic thermodynamic equilibrium conditions. However, such phase definition is inadequate for systems that are not at equilibrium in the classic thermodynamic sense, like fluid systems under flowing conditions. Complex fluids may exhibit instabilities like shear-banding flow and a non-equilibrium critical point where banding flow ends. At this point, the fluid undergoes a phase transition from heterogeneous to homogeneous states. An extended thermodynamic space of variables is considered to adequately address this situation, which includes non-conservative variables such as stress and shear rate. Hence, the current phase definition based on conservative variables does not apply to non-equilibrium phase diagrams. On this basis, a broader definition of phase is required. We propose that this broader definition considers the thermodynamic variables space of Extended Irreversible Thermodynamics and the mathematical conditions that ensure compatibility between equilibrium and non-equilibrium conditions for systems where phases are well described by thermodynamic potentials even out of equilibrium.
{"title":"Is there a need for an extended phase definition for systems far from equilibrium?","authors":"Fernando Bautista, Juan Paulo García-Sandoval, Octavio Manero","doi":"10.1515/jnet-2024-0063","DOIUrl":"https://doi.org/10.1515/jnet-2024-0063","url":null,"abstract":"Phase diagrams out of equilibrium have been the subject of intense research. An essential concept in these diagrams is the phase definition. Currently, that definition is well established for systems at classic thermodynamic equilibrium conditions. However, such phase definition is inadequate for systems that are not at equilibrium in the classic thermodynamic sense, like fluid systems under flowing conditions. Complex fluids may exhibit instabilities like shear-banding flow and a non-equilibrium critical point where banding flow ends. At this point, the fluid undergoes a phase transition from heterogeneous to homogeneous states. An extended thermodynamic space of variables is considered to adequately address this situation, which includes non-conservative variables such as stress and shear rate. Hence, the current phase definition based on conservative variables does not apply to non-equilibrium phase diagrams. On this basis, a broader definition of phase is required. We propose that this broader definition considers the thermodynamic variables space of Extended Irreversible Thermodynamics and the mathematical conditions that ensure compatibility between equilibrium and non-equilibrium conditions for systems where phases are well described by thermodynamic potentials even out of equilibrium.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"67 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143417792","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：