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Xiulan Huai - One of the best experts on this subject based on the ideXlab platform.
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Heat Transfer and Entropy Generation Analysis of an Intermediate Heat Exchanger in ADS
Journal of Thermal Science, 2018Co-Authors: Yongwei Wang, Xiulan HuaiAbstract:The intermediate heat exchanger for enhancement heat transfer is the important equipment in the usage of nuclear energy. In the present work, heat transfer and entropy Generation of an intermediate heat exchanger (IHX) in the accelerator driven subcritical system (ADS) are investigated experimentally. The variation of entropy Generation Number with performance parameters of the IHX is analyzed, and effects of inlet conditions of the IHX on entropy Generation Number and heat transfer are discussed. Compared with the results at two working conditions of the constant mass flow rates of liquid lead-bismuth eutectic (LBE) and helium gas, the total pumping power all tends to reduce with the decreasing entropy Generation Number, but the variations of the effectiveness, Number of transfer units and thermal capacity rate ratio are inconsistent, and need to analyze respectively. With the increasing inlet mass flow rate or LBE inlet temperature, the entropy Generation Number increases and the heat transfer is enhanced, while the opposite trend occurs with the increasing helium gas inlet temperature. The further study is necessary for obtaining the optimized operation parameters of the IHX to minimize entropy Generation and enhance heat transfer.
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Thermodynamic analysis of an isopropanol–acetone–hydrogen chemical heat pump
International Journal of Energy Research, 2014Co-Authors: Jiangfeng Guo, Xiulan HuaiAbstract:SUMMARY An isopropanol–acetone–hydrogen chemical heat pump is investigated in the ASPEN Plus shell, the influences of some important operation parameters on the six different evaluation criteria are presented, and the different evaluation criteria for the heat pump are also analyzed. The decrease of distillation to feed ratio improves the performance of the chemical heat pump, and the increase of endothermic reaction temperature improves the performance of heat pump based on first law of thermodynamics but weakens the performance of heat pump from the viewpoint of second law of thermodynamics. There exists an optimum reflux ratio in terms of enthalpy efficiency, entransy efficiency, and exergy efficiency, but the performance of heat pump deteriorates as the reflux ratio increases in terms of entropy Generation Number, revised entropy Generation Number, and ecological COP. The entransy efficiency tends to integrate the behaviors of enthalpy efficiency and exergy efficiency. Compared with entropy Generation Number, the behavior of revised entropy Generation Number is more consistent with the practice. Copyright © 2014 John Wiley & Sons, Ltd.
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The effect of temperature-dependent viscosity on entropy Generation in curved square microchannel
Chemical Engineering and Processing: Process Intensification, 2012Co-Authors: Jiangfeng Guo, Yujia Tao, Xiulan HuaiAbstract:Abstract The effect of temperature-dependent viscosity on the thermodynamic performance of the curved square microchannel in laminar flow is numerically investigated in terms of entropy Generation. The classical Navier–Stokes equations and constant wall temperature boundary conditions are adopted; aniline and ethylene glycol are selected as the working fluids. The results show that the Nusselt Number, heat transfer entropy Generation Number and frictional entropy Generation Number are less for the temperature-dependent viscosity than for the constant viscosity when aniline is heated. However, the opposite conclusions can be drawn when aniline is cooled. The total entropy Generation Number extrema exist for the cases of aniline heated and cooled. The differences between the results obtained with and without considering temperature-dependent viscosity is more obvious when aniline is cooled than when aniline is heated. The difference between the Brinkman Numbers obtained with and without considering temperature-dependent viscosity grows as the mass flow rate increases when ethylene glycol is heated. The temperature-dependent effect on entropy Generation is more pronounced for ethylene glycol than for aniline, since the former has larger viscosity than the latter.
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Viscous dissipation effect on entropy Generation in curved square microchannels
Energy, 2011Co-Authors: Jiangfeng Guo, Jun Cai, Xiulan HuaiAbstract:The viscous dissipation effect on the thermodynamic performance of the curved square microchannels in laminar flow is numerically investigated. The classical Navier–Stokes equations are adopted; aniline and ethylene glycol are selected as the working fluids. The results show that the heat transfer entropy Generation Number and frictional entropy Generation Number augment relatively under viscous dissipation effect for the case of fluid heated, and the opposite results can be found for the case of fluid cooled. The heat transfer entropy Generation Number increases with Reynolds Number at large Reynolds Number region under viscous dissipation effect when ethylene glycol is heated. The total entropy Generation Number extremum exists for aniline, and the extremum happens earlier when aniline is heated than when aniline is cooled. The smaller the curvature radius is, the earlier the extremum appears. The extremum does not occur for ethylene glycol due to the predomination of frictional entropy Generation in the total entropy Generation.
Mehdi Hashemi-tilehnoee - One of the best experts on this subject based on the ideXlab platform.
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Second law analysis of magneto-natural convection in a nanofluid filled wavy-hexagonal porous enclosure
International Journal of Numerical Methods for Heat & Fluid Flow, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Davood Domiri Ganji, Ali J. ChamkhaAbstract:Natural convection heat transfer analysis can be completed using entropy Generation analysis. This study aims to accomplish both the natural convection heat transfer and entropy Generation analyses for a hexagonal cavity loaded with Cu-H2O nanoliquid subjected to an oriented magnetic field.,Control volume-based finite element method is applied to solve the non-dimensional forms of governing equations and then, the entropy Generation Number is computed.,The results portray that both the average Nusselt and entropy Generation Numbers boost with increasing aspect ratio for each value of the undulation Number, while both of them decrease with increasing the undulation Number for each amplitude parameter. There is a maximum value for the entropy Generation Number at a specified value of Hartmann Number. Also, there is a minimum value for the entropy Generation Number at a specified value of angle of the magnetic field. When the volume fraction of nanoparticles grows, the average Nusselt Number increases and the entropy Generation Number declines. The entropy Generation Number attains to a maximum value at Ha = 14 for each value of aspect ratio. The average Nusselt Number ascends 2.9 per cent and entropy Generation Number decreases 1.3 per cent for Ha = 0 when ϕ increases from 0 to 4 per cent.,A hexagonal enclosure (complex geometry), which has many industrial applications, is chosen in this study. Not only the characteristics of heat transfer are investigated but also entropy Generation analysis is performed in this study. The ecological coefficient of performance for enclosures is calculated, too.
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Entropy Generation and economic analyses in a nanofluid filled L-shaped enclosure subjected to an oriented magnetic field
Applied Thermal Engineering, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Davood Domiri GanjiAbstract:Abstract Natural convected heat transportation attributes can be elaborated better using entropy Generation analysis. In current framework, we scrutinized magnetized Al2O3-H2O nanomaterial natural convection based on entropy Generation and L-shaped cavity. Non-dimensional forms of governing expressions are computed through Control Volume-based Finite Element Method (CVFEM). Entropy Generation Number is calculated. Features of active parameters e.g. Rayleigh Number, nanoparticles volume-fraction, nanoparticle shape, Hartmann Number, magnetic field angle and aspect ratio versus average heat transportation rate (Nusselt Number) and the entropy Generation Number are investigated. For the first time, an economic analysis is introduced for evaluating the performance of the enclosure with consideration cost of nanofluid. Also, in order to assess the performance of the enclosure, six criteria are introduced which two of them are based on the cost of nanofluids. The results were compared with references and a good compromise was seen. According to the results, both the entropy Generation Number and average heat transportation rate rise when Rayleigh Number upsurges. The average heat transportation rate rises with ascending the nanoparticle volume-fraction whereas the entropy Generation Number declines when nanoparticles concentration ascends. The entropy Generation Number decreases 15.14% and 8.15% for H a = 25 and H a = 75 , respectively, when ϕ increases from 0 to 0.1.
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Numerical analysis of entropy Generation of a nanofluid in a semi-annulus porous enclosure with different nanoparticle shapes in the presence of a magnetic field
The European Physical Journal Plus, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, R. Nuraei, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in cavities. The next step is the study of entropy Generation. The object of the present work is the investigation of the entropy Generation in a semi-annulus porous cavity filled with Cu-water nanofluid in the presence of a magnetic field. The outer and inner semi-circular walls are kept at constant temperatures whereas the two other walls are insulated. Firstly, the governing equations (i.e. continuity, momentum and energy equations) are numerically solved by the Control Volume based Finite Element Method (CVFEM) and then the entropy Generation Number is calculated. The effects of the Rayleigh Number, Darcy Number, Hartmann Number, angle of magnetic field, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure, Number and amplitude of undulation in the wavy wall on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase. Also, the entropy Generation Number decreases with increasing the Hartmann Number whereas it increases as the Darcy Number increases.
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Entropy Generation in a nanofluid-filled semi-annulus cavity by considering the shape of nanoparticles
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in the cavities. The next step is study of entropy Generation. The object of the present work is investigation of the entropy Generation in a semi-annulus cavity filled with Cu–water nanofluid. The outer and inner semicircular walls are kept at constant temperatures, whereas the two other walls are insulated. Firstly, the governing equations (i.e., continuity, momentum and energy equations) are numerically solved by the control volume-based finite element method, and then, the entropy Generation Number is calculated. The effects of the Rayleigh Number, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature, and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase.
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A computational framework for natural convective hydromagnetic flow via inclined cavity: An analysis subjected to entropy Generation
Journal of Molecular Liquids, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Zeeshan Asghar, Davood Domiri GanjiAbstract:Abstract One of the most interested and essential subjective in mechanical science is natural convection analysis in a cavity. Thus, natural convective flow and entropy Generation are scrutinized numerically subjected to magnetic field effect in a semi-annulus enclosure which known as the effect of magneto-hydrodynamic (MHD). Firstly, the governing expressions are rewritten in non-dimensional form utilizing the definition of dimensionless parameters, stream function, and vorticity. Secondly, the entropy Generation equation is expressed in non-dimensional form. Then governing non-dimensional expressions are computed by control finite element method (CVFEM). Furthermore, the governing expressions are computed employing finite volume method (FVM) utilizing ANSYS Fluent CFD code. A novel criterion for determination of thermal characteristics of cavity based on thermodynamics second relation is introduced that is called ecological coefficient of performance (ECOP). Flow and heat transport features in addition to entropy Generation Number are examined for distinct values of the Rayleigh Number (Ra = 103, 104, 105), the orientation of the magnetic field (β = 0°, 15°, 30°, 45°, 60°, 75°, 90°), and Hartmann Number (Ha = 0, 5, 10, 15, 20). For validation, the entropy Generation Number and average Nusselt Number are compared with those available in literature and excellent agreement is observed. Isotherms and streamlines are calculated using CVFEM and FVM. Some correlations for entropy Generation Number are proposed. The results show that for constant Rayleigh Number, the entropy Generation Number decays with increasing Hartmann Number. Also, for each Hartmann Number, there is an optimum inclination angle of magnetic field that gives a minimum for entropy Generation Number and a maximum for ECOP at each Rayleigh Number.
Davood Domiri Ganji - One of the best experts on this subject based on the ideXlab platform.
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Second law analysis of magneto-natural convection in a nanofluid filled wavy-hexagonal porous enclosure
International Journal of Numerical Methods for Heat & Fluid Flow, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Davood Domiri Ganji, Ali J. ChamkhaAbstract:Natural convection heat transfer analysis can be completed using entropy Generation analysis. This study aims to accomplish both the natural convection heat transfer and entropy Generation analyses for a hexagonal cavity loaded with Cu-H2O nanoliquid subjected to an oriented magnetic field.,Control volume-based finite element method is applied to solve the non-dimensional forms of governing equations and then, the entropy Generation Number is computed.,The results portray that both the average Nusselt and entropy Generation Numbers boost with increasing aspect ratio for each value of the undulation Number, while both of them decrease with increasing the undulation Number for each amplitude parameter. There is a maximum value for the entropy Generation Number at a specified value of Hartmann Number. Also, there is a minimum value for the entropy Generation Number at a specified value of angle of the magnetic field. When the volume fraction of nanoparticles grows, the average Nusselt Number increases and the entropy Generation Number declines. The entropy Generation Number attains to a maximum value at Ha = 14 for each value of aspect ratio. The average Nusselt Number ascends 2.9 per cent and entropy Generation Number decreases 1.3 per cent for Ha = 0 when ϕ increases from 0 to 4 per cent.,A hexagonal enclosure (complex geometry), which has many industrial applications, is chosen in this study. Not only the characteristics of heat transfer are investigated but also entropy Generation analysis is performed in this study. The ecological coefficient of performance for enclosures is calculated, too.
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Entropy Generation and economic analyses in a nanofluid filled L-shaped enclosure subjected to an oriented magnetic field
Applied Thermal Engineering, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Davood Domiri GanjiAbstract:Abstract Natural convected heat transportation attributes can be elaborated better using entropy Generation analysis. In current framework, we scrutinized magnetized Al2O3-H2O nanomaterial natural convection based on entropy Generation and L-shaped cavity. Non-dimensional forms of governing expressions are computed through Control Volume-based Finite Element Method (CVFEM). Entropy Generation Number is calculated. Features of active parameters e.g. Rayleigh Number, nanoparticles volume-fraction, nanoparticle shape, Hartmann Number, magnetic field angle and aspect ratio versus average heat transportation rate (Nusselt Number) and the entropy Generation Number are investigated. For the first time, an economic analysis is introduced for evaluating the performance of the enclosure with consideration cost of nanofluid. Also, in order to assess the performance of the enclosure, six criteria are introduced which two of them are based on the cost of nanofluids. The results were compared with references and a good compromise was seen. According to the results, both the entropy Generation Number and average heat transportation rate rise when Rayleigh Number upsurges. The average heat transportation rate rises with ascending the nanoparticle volume-fraction whereas the entropy Generation Number declines when nanoparticles concentration ascends. The entropy Generation Number decreases 15.14% and 8.15% for H a = 25 and H a = 75 , respectively, when ϕ increases from 0 to 0.1.
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Numerical analysis of entropy Generation of a nanofluid in a semi-annulus porous enclosure with different nanoparticle shapes in the presence of a magnetic field
The European Physical Journal Plus, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, R. Nuraei, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in cavities. The next step is the study of entropy Generation. The object of the present work is the investigation of the entropy Generation in a semi-annulus porous cavity filled with Cu-water nanofluid in the presence of a magnetic field. The outer and inner semi-circular walls are kept at constant temperatures whereas the two other walls are insulated. Firstly, the governing equations (i.e. continuity, momentum and energy equations) are numerically solved by the Control Volume based Finite Element Method (CVFEM) and then the entropy Generation Number is calculated. The effects of the Rayleigh Number, Darcy Number, Hartmann Number, angle of magnetic field, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure, Number and amplitude of undulation in the wavy wall on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase. Also, the entropy Generation Number decreases with increasing the Hartmann Number whereas it increases as the Darcy Number increases.
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Entropy Generation in a nanofluid-filled semi-annulus cavity by considering the shape of nanoparticles
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in the cavities. The next step is study of entropy Generation. The object of the present work is investigation of the entropy Generation in a semi-annulus cavity filled with Cu–water nanofluid. The outer and inner semicircular walls are kept at constant temperatures, whereas the two other walls are insulated. Firstly, the governing equations (i.e., continuity, momentum and energy equations) are numerically solved by the control volume-based finite element method, and then, the entropy Generation Number is calculated. The effects of the Rayleigh Number, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature, and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase.
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A computational framework for natural convective hydromagnetic flow via inclined cavity: An analysis subjected to entropy Generation
Journal of Molecular Liquids, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Zeeshan Asghar, Davood Domiri GanjiAbstract:Abstract One of the most interested and essential subjective in mechanical science is natural convection analysis in a cavity. Thus, natural convective flow and entropy Generation are scrutinized numerically subjected to magnetic field effect in a semi-annulus enclosure which known as the effect of magneto-hydrodynamic (MHD). Firstly, the governing expressions are rewritten in non-dimensional form utilizing the definition of dimensionless parameters, stream function, and vorticity. Secondly, the entropy Generation equation is expressed in non-dimensional form. Then governing non-dimensional expressions are computed by control finite element method (CVFEM). Furthermore, the governing expressions are computed employing finite volume method (FVM) utilizing ANSYS Fluent CFD code. A novel criterion for determination of thermal characteristics of cavity based on thermodynamics second relation is introduced that is called ecological coefficient of performance (ECOP). Flow and heat transport features in addition to entropy Generation Number are examined for distinct values of the Rayleigh Number (Ra = 103, 104, 105), the orientation of the magnetic field (β = 0°, 15°, 30°, 45°, 60°, 75°, 90°), and Hartmann Number (Ha = 0, 5, 10, 15, 20). For validation, the entropy Generation Number and average Nusselt Number are compared with those available in literature and excellent agreement is observed. Isotherms and streamlines are calculated using CVFEM and FVM. Some correlations for entropy Generation Number are proposed. The results show that for constant Rayleigh Number, the entropy Generation Number decays with increasing Hartmann Number. Also, for each Hartmann Number, there is an optimum inclination angle of magnetic field that gives a minimum for entropy Generation Number and a maximum for ECOP at each Rayleigh Number.
Seyyed Masoud Seyyedi - One of the best experts on this subject based on the ideXlab platform.
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Second law analysis of magneto-natural convection in a nanofluid filled wavy-hexagonal porous enclosure
International Journal of Numerical Methods for Heat & Fluid Flow, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Davood Domiri Ganji, Ali J. ChamkhaAbstract:Natural convection heat transfer analysis can be completed using entropy Generation analysis. This study aims to accomplish both the natural convection heat transfer and entropy Generation analyses for a hexagonal cavity loaded with Cu-H2O nanoliquid subjected to an oriented magnetic field.,Control volume-based finite element method is applied to solve the non-dimensional forms of governing equations and then, the entropy Generation Number is computed.,The results portray that both the average Nusselt and entropy Generation Numbers boost with increasing aspect ratio for each value of the undulation Number, while both of them decrease with increasing the undulation Number for each amplitude parameter. There is a maximum value for the entropy Generation Number at a specified value of Hartmann Number. Also, there is a minimum value for the entropy Generation Number at a specified value of angle of the magnetic field. When the volume fraction of nanoparticles grows, the average Nusselt Number increases and the entropy Generation Number declines. The entropy Generation Number attains to a maximum value at Ha = 14 for each value of aspect ratio. The average Nusselt Number ascends 2.9 per cent and entropy Generation Number decreases 1.3 per cent for Ha = 0 when ϕ increases from 0 to 4 per cent.,A hexagonal enclosure (complex geometry), which has many industrial applications, is chosen in this study. Not only the characteristics of heat transfer are investigated but also entropy Generation analysis is performed in this study. The ecological coefficient of performance for enclosures is calculated, too.
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Entropy Generation and economic analyses in a nanofluid filled L-shaped enclosure subjected to an oriented magnetic field
Applied Thermal Engineering, 2020Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Davood Domiri GanjiAbstract:Abstract Natural convected heat transportation attributes can be elaborated better using entropy Generation analysis. In current framework, we scrutinized magnetized Al2O3-H2O nanomaterial natural convection based on entropy Generation and L-shaped cavity. Non-dimensional forms of governing expressions are computed through Control Volume-based Finite Element Method (CVFEM). Entropy Generation Number is calculated. Features of active parameters e.g. Rayleigh Number, nanoparticles volume-fraction, nanoparticle shape, Hartmann Number, magnetic field angle and aspect ratio versus average heat transportation rate (Nusselt Number) and the entropy Generation Number are investigated. For the first time, an economic analysis is introduced for evaluating the performance of the enclosure with consideration cost of nanofluid. Also, in order to assess the performance of the enclosure, six criteria are introduced which two of them are based on the cost of nanofluids. The results were compared with references and a good compromise was seen. According to the results, both the entropy Generation Number and average heat transportation rate rise when Rayleigh Number upsurges. The average heat transportation rate rises with ascending the nanoparticle volume-fraction whereas the entropy Generation Number declines when nanoparticles concentration ascends. The entropy Generation Number decreases 15.14% and 8.15% for H a = 25 and H a = 75 , respectively, when ϕ increases from 0 to 0.1.
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Numerical analysis of entropy Generation of a nanofluid in a semi-annulus porous enclosure with different nanoparticle shapes in the presence of a magnetic field
The European Physical Journal Plus, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, R. Nuraei, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in cavities. The next step is the study of entropy Generation. The object of the present work is the investigation of the entropy Generation in a semi-annulus porous cavity filled with Cu-water nanofluid in the presence of a magnetic field. The outer and inner semi-circular walls are kept at constant temperatures whereas the two other walls are insulated. Firstly, the governing equations (i.e. continuity, momentum and energy equations) are numerically solved by the Control Volume based Finite Element Method (CVFEM) and then the entropy Generation Number is calculated. The effects of the Rayleigh Number, Darcy Number, Hartmann Number, angle of magnetic field, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure, Number and amplitude of undulation in the wavy wall on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase. Also, the entropy Generation Number decreases with increasing the Hartmann Number whereas it increases as the Darcy Number increases.
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Entropy Generation in a nanofluid-filled semi-annulus cavity by considering the shape of nanoparticles
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Davood Domiri Ganji, Mehdi Hashemi-tilehnoeeAbstract:One of the important problems in the field of heat transfer is the investigation of natural convection heat transfer in the cavities. The next step is study of entropy Generation. The object of the present work is investigation of the entropy Generation in a semi-annulus cavity filled with Cu–water nanofluid. The outer and inner semicircular walls are kept at constant temperatures, whereas the two other walls are insulated. Firstly, the governing equations (i.e., continuity, momentum and energy equations) are numerically solved by the control volume-based finite element method, and then, the entropy Generation Number is calculated. The effects of the Rayleigh Number, the nanoparticle volume fraction, the particle shape and the angle of turn for the enclosure on the entropy Generation Number are investigated. Also, a new criterion for the evaluation of cavity thermal performance is defined that is called ECOP. The results were compared with those of the literature, and good agreement was observed. The results show that the Nusselt Number and entropy Generation Number increase as the Rayleigh Number and the nanoparticle volume fraction increase.
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A computational framework for natural convective hydromagnetic flow via inclined cavity: An analysis subjected to entropy Generation
Journal of Molecular Liquids, 2019Co-Authors: Seyyed Masoud Seyyedi, Abdul Sattar Dogonchi, Mehdi Hashemi-tilehnoee, Muhammad Waqas, Zeeshan Asghar, Davood Domiri GanjiAbstract:Abstract One of the most interested and essential subjective in mechanical science is natural convection analysis in a cavity. Thus, natural convective flow and entropy Generation are scrutinized numerically subjected to magnetic field effect in a semi-annulus enclosure which known as the effect of magneto-hydrodynamic (MHD). Firstly, the governing expressions are rewritten in non-dimensional form utilizing the definition of dimensionless parameters, stream function, and vorticity. Secondly, the entropy Generation equation is expressed in non-dimensional form. Then governing non-dimensional expressions are computed by control finite element method (CVFEM). Furthermore, the governing expressions are computed employing finite volume method (FVM) utilizing ANSYS Fluent CFD code. A novel criterion for determination of thermal characteristics of cavity based on thermodynamics second relation is introduced that is called ecological coefficient of performance (ECOP). Flow and heat transport features in addition to entropy Generation Number are examined for distinct values of the Rayleigh Number (Ra = 103, 104, 105), the orientation of the magnetic field (β = 0°, 15°, 30°, 45°, 60°, 75°, 90°), and Hartmann Number (Ha = 0, 5, 10, 15, 20). For validation, the entropy Generation Number and average Nusselt Number are compared with those available in literature and excellent agreement is observed. Isotherms and streamlines are calculated using CVFEM and FVM. Some correlations for entropy Generation Number are proposed. The results show that for constant Rayleigh Number, the entropy Generation Number decays with increasing Hartmann Number. Also, for each Hartmann Number, there is an optimum inclination angle of magnetic field that gives a minimum for entropy Generation Number and a maximum for ECOP at each Rayleigh Number.
Jiangfeng Guo - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic analysis of an isopropanol–acetone–hydrogen chemical heat pump
International Journal of Energy Research, 2014Co-Authors: Jiangfeng Guo, Xiulan HuaiAbstract:SUMMARY An isopropanol–acetone–hydrogen chemical heat pump is investigated in the ASPEN Plus shell, the influences of some important operation parameters on the six different evaluation criteria are presented, and the different evaluation criteria for the heat pump are also analyzed. The decrease of distillation to feed ratio improves the performance of the chemical heat pump, and the increase of endothermic reaction temperature improves the performance of heat pump based on first law of thermodynamics but weakens the performance of heat pump from the viewpoint of second law of thermodynamics. There exists an optimum reflux ratio in terms of enthalpy efficiency, entransy efficiency, and exergy efficiency, but the performance of heat pump deteriorates as the reflux ratio increases in terms of entropy Generation Number, revised entropy Generation Number, and ecological COP. The entransy efficiency tends to integrate the behaviors of enthalpy efficiency and exergy efficiency. Compared with entropy Generation Number, the behavior of revised entropy Generation Number is more consistent with the practice. Copyright © 2014 John Wiley & Sons, Ltd.
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The effect of temperature-dependent viscosity on entropy Generation in curved square microchannel
Chemical Engineering and Processing: Process Intensification, 2012Co-Authors: Jiangfeng Guo, Yujia Tao, Xiulan HuaiAbstract:Abstract The effect of temperature-dependent viscosity on the thermodynamic performance of the curved square microchannel in laminar flow is numerically investigated in terms of entropy Generation. The classical Navier–Stokes equations and constant wall temperature boundary conditions are adopted; aniline and ethylene glycol are selected as the working fluids. The results show that the Nusselt Number, heat transfer entropy Generation Number and frictional entropy Generation Number are less for the temperature-dependent viscosity than for the constant viscosity when aniline is heated. However, the opposite conclusions can be drawn when aniline is cooled. The total entropy Generation Number extrema exist for the cases of aniline heated and cooled. The differences between the results obtained with and without considering temperature-dependent viscosity is more obvious when aniline is cooled than when aniline is heated. The difference between the Brinkman Numbers obtained with and without considering temperature-dependent viscosity grows as the mass flow rate increases when ethylene glycol is heated. The temperature-dependent effect on entropy Generation is more pronounced for ethylene glycol than for aniline, since the former has larger viscosity than the latter.
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Viscous dissipation effect on entropy Generation in curved square microchannels
Energy, 2011Co-Authors: Jiangfeng Guo, Jun Cai, Xiulan HuaiAbstract:The viscous dissipation effect on the thermodynamic performance of the curved square microchannels in laminar flow is numerically investigated. The classical Navier–Stokes equations are adopted; aniline and ethylene glycol are selected as the working fluids. The results show that the heat transfer entropy Generation Number and frictional entropy Generation Number augment relatively under viscous dissipation effect for the case of fluid heated, and the opposite results can be found for the case of fluid cooled. The heat transfer entropy Generation Number increases with Reynolds Number at large Reynolds Number region under viscous dissipation effect when ethylene glycol is heated. The total entropy Generation Number extremum exists for aniline, and the extremum happens earlier when aniline is heated than when aniline is cooled. The smaller the curvature radius is, the earlier the extremum appears. The extremum does not occur for ethylene glycol due to the predomination of frictional entropy Generation in the total entropy Generation.
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The Entropy Generation Minimisation based on the Revised Entropy Generation Number
International Journal of Exergy, 2010Co-Authors: Jiangfeng Guo, Lin ChengAbstract:In the present work, an improved Entropy Generation Minimisation (EGM) approach aiming at minimising the revised entropy Generation Number which is the non-dimensionalised entropy by the ratio of heat flow to the input temperature of the cold fluid is developed for a plate-fin heat exchanger design with multiple design variables with the help of genetic algorithm. It is found that the approach can decrease the total fan power dramatically and improve the exchanger effectiveness simultaneously. Finally, this approach is applied to a heat recovery system where the heat exchanger works as a component of the system.