The effect of Al 2 O 3 -water nanofluid on the heat transfer and entropy generation of laminar forced convection through isotropic porous media

This paper investigates the energetic and entropic characteristics of a microchannel with thick walls. A first order, catalytic chemical reaction is imposed on the inner surfaces of the microchannel walls and local thermal non-equilibrium approach is employed to analyse heat transfer within the porous section of the microchannel. Further, endo/exothermic physicochemical processes are incorporated into the fluid phase and solid structure of the microchannel. Two models describing the fluid-porous interface conditions known as Models A and B are incorporated. It is shown that for both interface models, and with the considered parametric values, the optimum thickness of the porous insert to achieve the maximum Nu is around 0.6. However, when PEC is considered this optimum thickness may vary between 0 and 0.5. It is further shown that depending on the specification of the microreactor, either of Models A or B may result in the prediction of the minimum total entropy generation rate. It is also demonstrated that by altering the endothermicity of the microreactor it is possible to find an optimal value, which minimises the total rate of entropy generation.

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“…Also, PEC provides an insight into both heat transfer and entropy generation performances of the microreactor and is calculated by [50] = .…”

Section: Dimensionless Parameters and Non-dimensionalised Equationsmentioning

confidence: 99%

Energetic and entropic analyses of double-diffusive, forced convection heat and mass transfer in microreactors assisted with nanofluid

Guthrie

Torabi

Karimi

2018

J Therm Anal Calorim

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“…This parameter is another tool to assess the thermodynamic performance of the system, while simultaneously incorporating the Nusselt number into the calculations. PEC is defined as: Performance evaluation criterion (PEC) is a means of measuring the performance of thermal systems that takes into account both first and second law characteristics [52]. This parameter is another tool to assess the thermodynamic performance of the system, while simultaneously incorporating the Nusselt number into the calculations.…”

Section: Entropy Generation and Performance Evaluation Criterionmentioning

confidence: 99%

Non-Equilibrium Thermodynamic Analysis of Double Diffusive, Nanofluid Forced Convection in Catalytic Microreactors with Radiation Effects

Govone

Torabi

Hunt

et al. 2017

Entropy

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This paper presents a theoretical investigation of the second law performance of double diffusive forced convection in microreactors with the inclusion of nanofluid and radiation effects. The investigated microreactors consist of a single microchannel, fully filled by a porous medium. The transport of heat and mass are analysed by including the thick walls and a first order, catalytic chemical reaction on the internal surfaces of the microchannel. Two sets of thermal boundary conditions are considered on the external surfaces of the microchannel; (1) constant temperature and (2) constant heat flux boundary condition on the lower wall and convective boundary condition on the upper wall. The local thermal non-equilibrium approach is taken to thermally analyse the porous section of the system. The mass dispersion equation is coupled with the transport of heat in the nanofluid flow through consideration of Soret effect. The problem is analytically solved and illustrations of the temperature fields, Nusselt number, total entropy generation rate and performance evaluation criterion (PEC) are provided. It is shown that the radiation effect tends to modify the thermal behaviour within the porous section of the system. The radiation parameter also reduces the overall temperature of the system. It is further demonstrated that, expectedly, the nanoparticles reduce the temperature of the system and increase the Nusselt number. The total entropy generation rate and consequently PEC shows a strong relation with radiation parameter and volumetric concentration of nanoparticles.

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“…They demonstrated that minimization of entropy can be achieved via a higher solid volume fraction of nanoparticle and suction-injection Reynolds number. Torabi et al [24] demonstrated the nanofluid flow in porous media considering Al 2 O 3 /water. They noted that the Bejan number increased with the nanoparticle concentration.…”

Section: Introductionmentioning

confidence: 99%

Flow of colloidal suspension and irreversibility analysis with aggregation kinematics of nanoparticles in a microchannel

Sindhu

Gireesha

2020

Appl. Math. Mech.-Engl. Ed.

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The current exploration focuses on the ethylene glycol (EG) based nanoliquid flow in a microchannel. The effectiveness of the internal heat source and linear radiation is reflected in the present investigation. The estimation of suitable thermal conductivity model has affirmative impact on the convective heat transfer phenomenon. The examination is conceded with the nanoparticle aggregation demonstrated by the Maxwell-Bruggeman and Krieger-Dougherty models which tackle the formation of nanolayer. These models effectively describe the thermal conductivity and viscosity correspondingly. The dimensionless mathematical expressions are solved numerically by the Runge Kutta Fehlberg approach. A higher thermal field is attained for the Bruggeman model due to the formation of thermal bridge. A second law analysis is carried out to predict the sources of irreversibility associated with the thermal system. It is remarked that lesser entropy generation is obtained for the aggregation model. The entropy generation rate declines with the slip flow and the thermal heat flux. A notable enhancement in the Bejan number is attained by increasing the Biot number. It is established that the nanoparticle aggragation model exhibits a higher Bejan number in comparision with the usual flow model.

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The effect of Al 2 O 3 -water nanofluid on the heat transfer and entropy generation of laminar forced convection through isotropic porous media

Cited by 31 publications

References 40 publications

Energetic and entropic analyses of double-diffusive, forced convection heat and mass transfer in microreactors assisted with nanofluid

Energetic and entropic analyses of double-diffusive, forced convection heat and mass transfer in microreactors assisted with nanofluid

Non-Equilibrium Thermodynamic Analysis of Double Diffusive, Nanofluid Forced Convection in Catalytic Microreactors with Radiation Effects

Flow of colloidal suspension and irreversibility analysis with aggregation kinematics of nanoparticles in a microchannel

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