Based on finite-time-thermodynamic theory and the model established in previous literature, the multi-objective optimization analysis for an endoreversible closed Atkinson cycle is conducted through using the NSGA-II algorithm. With the final state point temperature (<jats:italic>T</jats:italic> <jats:sub>2</jats:sub>) of cycle compression process as the optimization variable and the thermal efficiency (<jats:italic>η</jats:italic>), the dimensionless efficient power (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:msub> <m:mrow> <m:mover accent="true"> <m:mrow> <m:mi>E</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> <m:mrow> <m:mi>P</m:mi> </m:mrow> </m:msub> </m:math> <jats:tex-math> ${bar{E}}_{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_jnetdy-2023-0051_ineq_001.png" /> </jats:alternatives> </jats:inline-formula>), the dimensionless ecological function (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:mover accent="true"> <m:mrow> <m:mi>E</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{E}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_jnetdy-2023-0051_ineq_002.png" /> </jats:alternatives> </jats:inline-formula>) and the dimensionless power (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:mover accent="true"> <m:mrow> <m:mi>P</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_jnetdy-2023-0051_ineq_003.png" /> </jats:alternatives> </jats:inline-formula>) as the optimization objectives, the influences of <jats:italic>T</jats:italic> <jats:sub>2</jats:sub> on the four optimization objectives are analyzed, multi-objective optimization analyses of single-, two-, three- and four-objective are conducted, and the optimal cycle optimization objective combination is chosen by using three decision-making methods which include LINMAP, TOPSIS, and Shannon Entropy. The result shows that when four-objective optimization is conducted, with the ascent of <jats:italic>T</jats:italic> <jats:sub>2</jats:sub>, <jats:inline-formula> <jats:alternatives> <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:mover accent="true"> <m:mrow> <m:mi>P</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_jnetdy-2023-0051_ineq_004.png" /> </jats:alternatives> </jats:inline-formula> descends, <jats:italic>η</jats:italic> ascends, both <jats:inline-formula> <jats:alternatives> <m:math xmlns:m="http:
基于有限时间热力学理论和前人建立的模型，利用NSGA-II算法对内可逆封闭Atkinson循环进行多目标优化分析。以循环压缩过程最终状态点温度(t2)为优化变量，以热效率(η)、无量纲效率功率(E′P ${bar{E}}_{P}$)、无量纲生态函数(E′$bar{E}$)和无量纲功率(P′$bar{P}$)为优化目标，分析了t2对4个优化目标的影响，单、采用LINMAP、TOPSIS和Shannon熵三种决策方法，选择最优周期优化目标组合。结果表明，在进行四目标优化时，随着t2的增大，P $bar{P}$减小，η增大，E $ $bar{E}$和E $ P ${bar{E}}_{P}$均先增大后减小。在这种情况下，香农熵决策方法的偏差指数最小，为0.2657，因此其优化结果为最优。多目标优化结果可为实际闭式阿特金森循环热机的设计提供一定的指导。
{"title":"Multi-objective optimization of an endoreversible closed Atkinson cycle","authors":"Zheng Gong, Yanlin Ge, Lingen Chen, Huijun Feng","doi":"10.1515/jnet-2023-0051","DOIUrl":"https://doi.org/10.1515/jnet-2023-0051","url":null,"abstract":"Based on finite-time-thermodynamic theory and the model established in previous literature, the multi-objective optimization analysis for an endoreversible closed Atkinson cycle is conducted through using the NSGA-II algorithm. With the final state point temperature (<jats:italic>T</jats:italic> <jats:sub>2</jats:sub>) of cycle compression process as the optimization variable and the thermal efficiency (<jats:italic>η</jats:italic>), the dimensionless efficient power (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <m:msub> <m:mrow> <m:mover accent=\"true\"> <m:mrow> <m:mi>E</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> <m:mrow> <m:mi>P</m:mi> </m:mrow> </m:msub> </m:math> <jats:tex-math> ${bar{E}}_{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jnetdy-2023-0051_ineq_001.png\" /> </jats:alternatives> </jats:inline-formula>), the dimensionless ecological function (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <m:mrow> <m:mover accent=\"true\"> <m:mrow> <m:mi>E</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{E}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jnetdy-2023-0051_ineq_002.png\" /> </jats:alternatives> </jats:inline-formula>) and the dimensionless power (<jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <m:mrow> <m:mover accent=\"true\"> <m:mrow> <m:mi>P</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jnetdy-2023-0051_ineq_003.png\" /> </jats:alternatives> </jats:inline-formula>) as the optimization objectives, the influences of <jats:italic>T</jats:italic> <jats:sub>2</jats:sub> on the four optimization objectives are analyzed, multi-objective optimization analyses of single-, two-, three- and four-objective are conducted, and the optimal cycle optimization objective combination is chosen by using three decision-making methods which include LINMAP, TOPSIS, and Shannon Entropy. The result shows that when four-objective optimization is conducted, with the ascent of <jats:italic>T</jats:italic> <jats:sub>2</jats:sub>, <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <m:mrow> <m:mover accent=\"true\"> <m:mrow> <m:mi>P</m:mi> </m:mrow> <m:mo>̄</m:mo> </m:mover> </m:mrow> </m:math> <jats:tex-math> $bar{P}$ </jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_jnetdy-2023-0051_ineq_004.png\" /> </jats:alternatives> </jats:inline-formula> descends, <jats:italic>η</jats:italic> ascends, both <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http:","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"83 7","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138437513","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}
The article utilizes the fractional bioheat model in spherical coordinates to explain the transfer of heat in living tissues during magnetic hyperthermia treatment for tumors. Maintaining therapeutic temperature is crucial in magnetic fluid hyperthermia, which requires accurate estimations of power dissipation to determine the appropriate number of magnetic particles required for treatment. To address this problem, a hybrid numerical approach that combines Laplace transforms, change of variables, and modified discretization techniques is proposed in this paper. The study investigates the impact of the fractional parameter and differences in thermophysical properties between diseased and healthy tissue. The numerical temperature results are presented in a graph, and their validity is demonstrated by comparing them with previous literature.
{"title":"The effects of fractional time derivatives in bioheat conduction technique on tumor thermal therapy","authors":"Ibrahim Abbas, Aatef Hobiny, Alaa El-Bary","doi":"10.1515/jnet-2023-0065","DOIUrl":"https://doi.org/10.1515/jnet-2023-0065","url":null,"abstract":"The article utilizes the fractional bioheat model in spherical coordinates to explain the transfer of heat in living tissues during magnetic hyperthermia treatment for tumors. Maintaining therapeutic temperature is crucial in magnetic fluid hyperthermia, which requires accurate estimations of power dissipation to determine the appropriate number of magnetic particles required for treatment. To address this problem, a hybrid numerical approach that combines Laplace transforms, change of variables, and modified discretization techniques is proposed in this paper. The study investigates the impact of the fractional parameter and differences in thermophysical properties between diseased and healthy tissue. The numerical temperature results are presented in a graph, and their validity is demonstrated by comparing them with previous literature.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"50 1","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138293325","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}
Pub Date : 2023-10-25DOI: 10.1515/jnetdy-2023-0040
Bader Alshuraiaan
Abstract The paper evaluates a passive method for heat transfer improvement in heat exchangers, which implies the use of nanofluids. All calculations were carried out with a constant volumetric flow rate. The study examines three fluids with 0–4 % volume concentrations of CuO, MgO, and Al 2 O 3 particles. The results indicate an increase in the heat transfer coefficient with increasing temperature. An Al 2 O 3 nanofluid (4 % concentration) contributed to the best thermal performance. The incorporation of a 4 % content of MgO yielded an augmentation in heat transfer ranging from 15 % to 22 %, whereas an analogous concentration of CuO led to a more substantial enhancement of 25 %. Notably, the introduction of nanoparticles of Al 2 O 3 produces a remarkable augmentation in heat transfer performance, with potential improvements of up to 36 %. The Nusselt number increases with increasing particle volume fraction and Reynolds number, according to results obtained for several nanoparticles (Al 2 O 3 , CuO, SiO 2 , and ZnO) with volume percentages in the range of 1–4 % and nanoparticle diameters of 25–70 nm. For all nanofluids, the time-averaged Nusselt number rises with a solid phase volume fraction increase of less than 5 %.
{"title":"Strategies to improve the thermal performance of solar collectors","authors":"Bader Alshuraiaan","doi":"10.1515/jnetdy-2023-0040","DOIUrl":"https://doi.org/10.1515/jnetdy-2023-0040","url":null,"abstract":"Abstract The paper evaluates a passive method for heat transfer improvement in heat exchangers, which implies the use of nanofluids. All calculations were carried out with a constant volumetric flow rate. The study examines three fluids with 0–4 % volume concentrations of CuO, MgO, and Al 2 O 3 particles. The results indicate an increase in the heat transfer coefficient with increasing temperature. An Al 2 O 3 nanofluid (4 % concentration) contributed to the best thermal performance. The incorporation of a 4 % content of MgO yielded an augmentation in heat transfer ranging from 15 % to 22 %, whereas an analogous concentration of CuO led to a more substantial enhancement of 25 %. Notably, the introduction of nanoparticles of Al 2 O 3 produces a remarkable augmentation in heat transfer performance, with potential improvements of up to 36 %. The Nusselt number increases with increasing particle volume fraction and Reynolds number, according to results obtained for several nanoparticles (Al 2 O 3 , CuO, SiO 2 , and ZnO) with volume percentages in the range of 1–4 % and nanoparticle diameters of 25–70 nm. For all nanofluids, the time-averaged Nusselt number rises with a solid phase volume fraction increase of less than 5 %.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"C-29 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135113286","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}
Debashis Panda, Ashok Kumar Satapathy, Sunil Kr. Sarangi, Upendra Behera
Abstract The Gifford-McMahon cryocoolers are considered to be prominent candidates for the cooling of high-temperature superconducting magnets, liquefaction of permanent gases, helium recondensation in magnetic resonance imaging machines, cooling of superconducting quantum interference device, etc. In this paper, multi-dimensional numerical simulation is performed to visualize the oscillating heat and fluid flow processes that happen in a mechanically driven GM cryocooler. Influence of the ideal gas equation and real gas equation of states on the cooling behaviour is explained. The minimum achievable refrigeration temperature of a uniform mesh regenerator is compared with a multi-mesh regenerator. It is noticed that a multi-mesh regenerator produces a lower refrigeration temperature as compared to a uniform mesh regenerator. In addition to this, a one-dimensional simulation is conducted and results are compared with multi-dimensional numerical simulation. The no-load temperature value calculated by the one-dimensional model and multi-dimensional model with ideal gas is lower than that of real gas equations. Additionally, the refrigerating capacity calculated by the one-dimensional model and multi-dimensional model with the ideal gas equation is higher than those of the real gas equation of state.
{"title":"Multidimensional numerical simulation of thermodynamic and oscillating gas flow processes of a Gifford-McMahon cryocooler","authors":"Debashis Panda, Ashok Kumar Satapathy, Sunil Kr. Sarangi, Upendra Behera","doi":"10.1515/jnet-2023-0026","DOIUrl":"https://doi.org/10.1515/jnet-2023-0026","url":null,"abstract":"Abstract The Gifford-McMahon cryocoolers are considered to be prominent candidates for the cooling of high-temperature superconducting magnets, liquefaction of permanent gases, helium recondensation in magnetic resonance imaging machines, cooling of superconducting quantum interference device, etc. In this paper, multi-dimensional numerical simulation is performed to visualize the oscillating heat and fluid flow processes that happen in a mechanically driven GM cryocooler. Influence of the ideal gas equation and real gas equation of states on the cooling behaviour is explained. The minimum achievable refrigeration temperature of a uniform mesh regenerator is compared with a multi-mesh regenerator. It is noticed that a multi-mesh regenerator produces a lower refrigeration temperature as compared to a uniform mesh regenerator. In addition to this, a one-dimensional simulation is conducted and results are compared with multi-dimensional numerical simulation. The no-load temperature value calculated by the one-dimensional model and multi-dimensional model with ideal gas is lower than that of real gas equations. Additionally, the refrigerating capacity calculated by the one-dimensional model and multi-dimensional model with the ideal gas equation is higher than those of the real gas equation of state.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"33 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135365513","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 A finite-time thermodynamic (FTT) model of three-heat-reservoir thermal Brownian refrigerator is established in this paper. This model can be equivalent to the coupling of a thermal Brownian engine and a thermal Brownian refrigerator with heat transfer effects. Expressions for cooling load and coefficient of performance (COP) are derived by combining FTT and non-equilibrium thermodynamics (NET). The system performance is studied and compared with those of previous models. For fixed internal parameters, the thermal conductance distributions among three heat exchangers are optimized for maximal cooling load. For fixed inventory allocations, the internal parameters are also optimized for maximal cooling load. Finally, the double-maximum cooling load is obtained by optimizing internal parameters and external thermal conductance distributions simultaneously, and the optimal operating temperatures are also derived. Results show that half of total thermal conductance should be placed in condenser to reject heat to ambient under maximal cooling load regime. The heat transfer determines system performance by controlling the working temperatures and the coupling of two external loads. The system works in reversible state when COP reaches its maximum value. The new performance limits can predict that of three-heat-reservoir thermal Brownian refrigerator more accurately, and also include those of NET model.
{"title":"Heat transfer effect on the performance of three-heat-reservoir thermal Brownian refrigerator","authors":"Congzheng Qi, Lingen Chen, Yanlin Ge, Huijun Feng","doi":"10.1515/jnet-2023-0050","DOIUrl":"https://doi.org/10.1515/jnet-2023-0050","url":null,"abstract":"Abstract A finite-time thermodynamic (FTT) model of three-heat-reservoir thermal Brownian refrigerator is established in this paper. This model can be equivalent to the coupling of a thermal Brownian engine and a thermal Brownian refrigerator with heat transfer effects. Expressions for cooling load and coefficient of performance (COP) are derived by combining FTT and non-equilibrium thermodynamics (NET). The system performance is studied and compared with those of previous models. For fixed internal parameters, the thermal conductance distributions among three heat exchangers are optimized for maximal cooling load. For fixed inventory allocations, the internal parameters are also optimized for maximal cooling load. Finally, the double-maximum cooling load is obtained by optimizing internal parameters and external thermal conductance distributions simultaneously, and the optimal operating temperatures are also derived. Results show that half of total thermal conductance should be placed in condenser to reject heat to ambient under maximal cooling load regime. The heat transfer determines system performance by controlling the working temperatures and the coupling of two external loads. The system works in reversible state when COP reaches its maximum value. The new performance limits can predict that of three-heat-reservoir thermal Brownian refrigerator more accurately, and also include those of NET model.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135044125","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}
Noha M. Sayed, Hussien Noby, Kyaw Thu, Ahmed H. El-Shazly
Abstract Some of the previous investigations neglect the mass transfer contribution of the hydrophilic layer for modeling the Janus membrane that is used for direct contact membrane distillation (DCMD). This work studies the impact of adding such resistance on the performance of the DCMD, especially on the temperature polarization coefficient (TPC), thermal efficiency, and permeate flux. The commercial software Ansys 2020 was used to describe the transport behavior through the Janus membrane. The bulk-flow model was employed to evaluate the permeate flow through the hydrophilic layer for the first time. Simulation results were compared with the experimental results from the literature for validating the model, and a satisfactory agreement was found. Results demonstrated that the permeate flux increased by about 61.3 % with changing the porosity of the hydrophilic layer from 0.5 to 0.9 for the membrane with the lowest hydrophilic layer thickness. Moreover, the thermal conductivities of both layers contribute significantly to the DCMD’s overall performance enhancement. Vapour flux might be enhanced by increasing the hydrophilic layer’s thermal conductivity while decreasing the hydrophobic layer’s thermal conductivity. Finally, the DCMD thermal efficiency was investigated, for the first time, in terms of both layer characteristics.
{"title":"Improved modeling of Janus membrane considering the influence of hydrophilic layer characteristics","authors":"Noha M. Sayed, Hussien Noby, Kyaw Thu, Ahmed H. El-Shazly","doi":"10.1515/jnet-2023-0037","DOIUrl":"https://doi.org/10.1515/jnet-2023-0037","url":null,"abstract":"Abstract Some of the previous investigations neglect the mass transfer contribution of the hydrophilic layer for modeling the Janus membrane that is used for direct contact membrane distillation (DCMD). This work studies the impact of adding such resistance on the performance of the DCMD, especially on the temperature polarization coefficient (TPC), thermal efficiency, and permeate flux. The commercial software Ansys 2020 was used to describe the transport behavior through the Janus membrane. The bulk-flow model was employed to evaluate the permeate flow through the hydrophilic layer for the first time. Simulation results were compared with the experimental results from the literature for validating the model, and a satisfactory agreement was found. Results demonstrated that the permeate flux increased by about 61.3 % with changing the porosity of the hydrophilic layer from 0.5 to 0.9 for the membrane with the lowest hydrophilic layer thickness. Moreover, the thermal conductivities of both layers contribute significantly to the DCMD’s overall performance enhancement. Vapour flux might be enhanced by increasing the hydrophilic layer’s thermal conductivity while decreasing the hydrophobic layer’s thermal conductivity. Finally, the DCMD thermal efficiency was investigated, for the first time, in terms of both layer characteristics.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135110266","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 Based on the irreversible Otto cycle model, applying finite-time-thermodynamic theory, this paper takes power and efficiency as the objective functions, further studies the cycle performance under the condition of non-ideal gas working fluid, analyzes the effects of different loss items and freedom degree (d) of monatomic gas on the cycle performance, and compares performance differences of ideal gas and non-ideal gas under different specific heat models. The results demonstrate that, with the increase of d, the maximum-power-output (Pmax), the maximum-thermal-efficiency (ηmax), the corresponding optimal compression-ratio ( ( γ opt ) p ${({gamma }_{text{opt}})}_{p}$ ) and efficiency (η P ) at the Pmax point, and the corresponding optimal compression ratio ( ( γ opt ) η ${({gamma }_{text{opt}})}_{eta }$ ) and power (P η ) at the ηmax point will all increase; the Pmax, ( γ opt ) p ${({gamma }_{text{opt}})}_{p}$ , ηmax, ( γ opt ) η ${({gamma }_{text{opt}})}_{eta }$ , η p and P η will decrease with the increases of three irreversible losses; the specific heat model has only quantitative effect on cycle performance but no qualitative effect; under condition of non-ideal gas specific heat model, the power and efficiency are the smallest.
{"title":"Effect of non-ideal gas working fluid on power and efficiency performances of an irreversible Otto cycle","authors":"Di Wu, Y. Ge, Lingen Chen, Lei Tian","doi":"10.1515/jnet-2023-0036","DOIUrl":"https://doi.org/10.1515/jnet-2023-0036","url":null,"abstract":"Abstract Based on the irreversible Otto cycle model, applying finite-time-thermodynamic theory, this paper takes power and efficiency as the objective functions, further studies the cycle performance under the condition of non-ideal gas working fluid, analyzes the effects of different loss items and freedom degree (d) of monatomic gas on the cycle performance, and compares performance differences of ideal gas and non-ideal gas under different specific heat models. The results demonstrate that, with the increase of d, the maximum-power-output (Pmax), the maximum-thermal-efficiency (ηmax), the corresponding optimal compression-ratio ( ( γ opt ) p ${({gamma }_{text{opt}})}_{p}$ ) and efficiency (η P ) at the Pmax point, and the corresponding optimal compression ratio ( ( γ opt ) η ${({gamma }_{text{opt}})}_{eta }$ ) and power (P η ) at the ηmax point will all increase; the Pmax, ( γ opt ) p ${({gamma }_{text{opt}})}_{p}$ , ηmax, ( γ opt ) η ${({gamma }_{text{opt}})}_{eta }$ , η p and P η will decrease with the increases of three irreversible losses; the specific heat model has only quantitative effect on cycle performance but no qualitative effect; under condition of non-ideal gas specific heat model, the power and efficiency are the smallest.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":" ","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44655173","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 Radiative heat transport involving complex geometries is an important area of investigation. The formulation of the transport phenomenon is more involved and consideration of the proper treatment of the irregular geometry becomes necessary for accurate estimation of heat transfer rates. Therefore, the present study focuses on the modeling and the solution of the radiative transfer equation (RTE) in an absorbing, emitting, and isotropically scattering, participating media for complex geometries using the body-fitted coordinates. The RTE in an orthogonal coordinate system is formulated and is then numerically solved in conjunction with a numerically generated, body-fitted, curvilinear coordinate system. The geometries are considered to be opaque and, in the analysis, both the radiative as well as the non-radiative equilibrium cases are considered. The formulation is validated through the previously published results. Notable agreement is observed between the results and those reported earlier for different complex geometries and various properties of the participating media.
{"title":"Computational radiative transport in complex geometries using orthogonal coordinates","authors":"Md. Ershadul Haque, S. Mansoor, B. Yilbas","doi":"10.1515/jnet-2023-0009","DOIUrl":"https://doi.org/10.1515/jnet-2023-0009","url":null,"abstract":"Abstract Radiative heat transport involving complex geometries is an important area of investigation. The formulation of the transport phenomenon is more involved and consideration of the proper treatment of the irregular geometry becomes necessary for accurate estimation of heat transfer rates. Therefore, the present study focuses on the modeling and the solution of the radiative transfer equation (RTE) in an absorbing, emitting, and isotropically scattering, participating media for complex geometries using the body-fitted coordinates. The RTE in an orthogonal coordinate system is formulated and is then numerically solved in conjunction with a numerically generated, body-fitted, curvilinear coordinate system. The geometries are considered to be opaque and, in the analysis, both the radiative as well as the non-radiative equilibrium cases are considered. The formulation is validated through the previously published results. Notable agreement is observed between the results and those reported earlier for different complex geometries and various properties of the participating media.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":" ","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48120885","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}
Parsa Movahedi, Ali Jalali Qush Qayeh, Javad Rahbar Shahrouzi
Abstract In order to commercialize aqueous two-phase systems (ATPSs), not only the equilibrium data is essential, but also the knowledge of separation mechanisms, kinetics, settling time, and operational conditions are needed. Mixing duration and settling time are the most critical factors affecting separation and biomolecule partitioning in terms of economic aspects. This research aimed to find the desired conditions for separating cephalexin in an ATPS consisting of acetonitrile, glucose, and water. Firstly, the evolution of the interphase region was observed. Hereafter, to examine the effect of time on the experimental tie-lines and partition coefficient in non-equilibrium states, the settling time was varied from 2 min to 24 h. In addition, centrifugation was applied to help the separation at different time intervals and rotational speeds. The results of tie-lines slope and partitioning coefficients showed that the system approaches equilibrium after 5 h. However, using the centrifuge separation at 4000 rpm improved the separation time to 45 min, reaching 80 % of the actual partition coefficient. It can be concluded that with an acceptable tolerance in the partition coefficient, a remarkably diminished settling time is available for economic productivity in industrial units.
{"title":"Investigation of non-equilibrium separation time on the partitioning of cephalexin in an aqueous two-phase system composed of glucose and acetonitrile","authors":"Parsa Movahedi, Ali Jalali Qush Qayeh, Javad Rahbar Shahrouzi","doi":"10.1515/jnet-2023-0028","DOIUrl":"https://doi.org/10.1515/jnet-2023-0028","url":null,"abstract":"Abstract In order to commercialize aqueous two-phase systems (ATPSs), not only the equilibrium data is essential, but also the knowledge of separation mechanisms, kinetics, settling time, and operational conditions are needed. Mixing duration and settling time are the most critical factors affecting separation and biomolecule partitioning in terms of economic aspects. This research aimed to find the desired conditions for separating cephalexin in an ATPS consisting of acetonitrile, glucose, and water. Firstly, the evolution of the interphase region was observed. Hereafter, to examine the effect of time on the experimental tie-lines and partition coefficient in non-equilibrium states, the settling time was varied from 2 min to 24 h. In addition, centrifugation was applied to help the separation at different time intervals and rotational speeds. The results of tie-lines slope and partitioning coefficients showed that the system approaches equilibrium after 5 h. However, using the centrifuge separation at 4000 rpm improved the separation time to 45 min, reaching 80 % of the actual partition coefficient. It can be concluded that with an acceptable tolerance in the partition coefficient, a remarkably diminished settling time is available for economic productivity in industrial units.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":" ","pages":""},"PeriodicalIF":6.6,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45751585","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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