Entropy generation of natural heat exchange into a porous medium accumulated by a hybrid nanoliquid applying LTNE model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hosein Shaker ◽  
Mohsen Izadi ◽  
Ehsanolah Assareh ◽  
Sabir Ali Shehzad ◽  
Mikhail Sheremet
Keyword(s):  
Porous Medium ◽  
Heat Exchange ◽  
Entropy Generation ◽  
Viscous Friction ◽  
Rigid Wall ◽  
Solid Matrix ◽  
Thermal Conductivity Ratio ◽  
Thermal Gradients ◽  
Content Type ◽  
Friction Term

Purpose This study aims to use the thermal non-equilibrium approach to inquire the entropy production and conjugate natural heat exchange in a porous medium. Entropy generation is studied separately for the solid matrix and the hybrid nanoliquid. Design/methodology/approach The characteristic equations are unraveled by applying the finite element method. Mathematical relations are used to calculate the generated entropy for the hybrid nanoliquid and matrix structure. Findings Based on the results, the produced entropy and the viscous friction term associated with the hybrid nanoliquid phase are not affected by increasing the thermal conductivity ratio of the rigid wall to nanoliquid. Moreover, a higher amount of entropy is generated by the thermal gradients in the hybrid nanoliquid phase compared to the solid matrix. Originality/value No investigation in the literature has been reported in this context.

Effects of moving lid direction on mixed convection and entropy generation in a cubical cavity with longitudinal triangular fin insertion

2017 ◽  
Vol 27 (4) ◽  
pp. 839-860 ◽  
Author(s):  
Lioua Kolsi ◽  
Hakan F. Öztop ◽  
Nidal Abu-Hamdeh ◽  
Borjini Mohamad Naceur ◽  
Habib Ben Assia
Keyword(s):  
Mixed Convection ◽  
Entropy Generation ◽  
Three Dimensional ◽  
Thermal Conductivity Ratio ◽  
Governing Equations ◽  
Content Type ◽  
Driven Cavity ◽  
Triangular Fin ◽  
Cubical Cavity ◽  
3D Problem

Purpose The main purpose of this work is to arrive at a three-dimensional (3D) numerical solution on mixed convection in a cubic cavity with a longitudinally located triangular fin in different sides. Design/methodology/approach The 3D governing equations are solved via finite volume technique by writing a code in FORTRAN platform. The governing parameters are chosen as Richardson number, 0.01 ≤ Ri ≤ 10 and thermal conductivity ratio 0.01 ≤ Rc ≤ 100 for fixed parameters of Pr = 0.7 and Re = 100. Two cases are considered for a lid-driven wall from left to right (V+) and right to left (V−). Findings It is observed that entropy generation due to heat transfer becomes dominant onto entropy generation because of fluid friction. The most important parameter is the direction of the moving lid, and lower values are obtained when the lid moves from right to left. Originality The main originality of this work is to arrive at a solution of a 3D problem of mixed convection and entropy generation for lid-driven cavity with conductive triangular fin attachments.

Non-equilibrium natural convection in a differentially-heated nanofluid cavity partially filled with a porous medium

2019 ◽  
Vol 29 (8) ◽  
pp. 2524-2544 ◽  
Author(s):  
Mikhail A. Sheremet ◽  
Ioan Pop ◽  
A. Cihat Baytas
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Volume Fraction ◽  
Good Control ◽  
Solid Matrix ◽  
Content Type ◽  
Practical Applications ◽  
Nanofluid Viscosity ◽  
Non Equilibrium

Purpose This study aims to numerically analyze natural convection of alumina-water nanofluid in a differentially-heated square cavity partially filled with a heat-generating porous medium. A single-phase nanofluid model with experimental correlations for the nanofluid viscosity and thermal conductivity has been considered for the description of the nanoparticles transport effect in the present study. Local thermal non-equilibrium approach for the porous layer with the Brinkman-extended Darcy model has been used. Design/methodology/approach Dimensionless governing equations formulated using stream function, vorticity and temperature have been solved by the finite difference method. The effects of the Rayleigh number, Ostrogradsky number, Nield number and nanoparticles volume fraction on nanofluid flow, heat and mass transfer have been analyzed. Findings It has been revealed that the dimensionless heat transfer coefficient at the fluid/solid matrix interface can be a very good control parameter for the convective flow and heat transfer intensity. The present results are original and new for the study of non-equilibrium natural convection in a differentially-heated nanofluid cavity partially filled with a porous medium. Originality/value The results of this paper are new and original with many practical applications of nanofluids in the modern industry.

Double stratified stagnation-point flow of Williamson nanomaterial with entropy generation through a porous medium

2019 ◽  
Vol 30 (4) ◽  
pp. 1899-1922 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
M.Z. Kiyani ◽  
Tasawar Hayat ◽  
Muhammad Faisal Javed ◽  
I. Ahmad
Keyword(s):  
Porous Medium ◽  
Stagnation Point ◽  
Entropy Generation ◽  
Stagnation Point Flow ◽  
Double Stratification ◽  
Convective Boundary ◽  
Content Type ◽  
Homotopy Analysis ◽  
Basic Objective ◽  
Flow Through

Purpose This paper aims to address double-stratified stagnation-point flow of Williamson nanomaterial with entropy generation. Flow through porous medium is discussed. Energy equation is modeled in existence of viscous dissipation, Brownian motion and thermophoresis. Furthermore, convective boundary conditions are considered. Total entropy rate is presented. Design/methodology/approach The non-linear flow expressions are converted to ordinary ones by implementation of suitable transformations. The obtained ordinary system is tackled for series solutions via homotopy analysis method. Findings Till date no one has considered the irreversibility analysis in stagnation-point flow of Williamson nanomaterial with double stratification, porous medium and convective conditions. The basic objective of present research is to investigate the convective stagnation point flow of Williamson liquid with entropy concept and porous medium. Originality/value As per the authors’ knowledge, no such work is yet present in the literature.

Optimization of entropy generation in motion of magnetite-Fe3O4 nanoparticles due to curved stretching sheet of variable thickness

2019 ◽  
Vol 29 (9) ◽  
pp. 3347-3365
Author(s):  
Sumaira Qayyum ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi
Keyword(s):  
Porous Medium ◽  
Mixed Convection ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Variable Thickness ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Bejan Number ◽  
Content Type ◽  
Curvature Parameter

Purpose Investigation for convective flow of water-based nanofluid (composed of ferric oxide asnanoparticles) by curved stretching sheet of variable thickness is made. Bejan number andentropy generation analysis is presented in presence of viscous dissipation, mixed convectionand porous medium. Design/methodology/approach In this paper, by using NDSolve of MATHEMATICA, the nonlinear system of equations is solved. Velocity, temperature, Bejan number and entropy generation for involved dimensionless variables are discussed. Findings Increase in velocity is depicted for larger curvature parameter, and opposite trend is witnessed for higher nanoparticle volume concentration. Enhancement in temperature is seen for higher Eckert number while reverse behavior is noticed for larger curvature parameter. Entropy rate increases for variation of curvature parameter, Brinkman number and nanoparticle volume fraction. Bejan number decays for mixed convection and curvature parameters. Originality/value To the authors’ knowledge, there exists no study yet which describes flow by curved sheet of variable thickness. Such consideration with nanoparticles seems important task. Thus, the main objective here is to determine entropy generation in ferromagnetic nanofluid flow due to variable thickened curved stretching surface. Additionally, effects of Joule heating, porous medium, mixed convection and viscous dissipation are taken into account.

Entropy generation analysis during MHD natural convection flow of hybrid nanofluid in a square cavity containing a corrugated conducting block

2019 ◽  
Vol 30 (3) ◽  
pp. 1115-1136 ◽  
Author(s):  
Tahar Tayebi ◽  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Entropy Generation ◽  
Thermal Conductivity Ratio ◽  
Hybrid Nanofluid ◽  
Conductivity Ratio ◽  
Square Cavity ◽  
Content Type ◽  
Solid Block

Purpose The purpose of this paper is to study the influence of magnetic field on entropy generation and natural convection inside an enclosure filled with a hybrid nanofluid and having a conducting wavy solid block. Also, the effect of fluid–solid thermal conductivity ratio is investigated. Design/methodology/approach The governing equations that are formulated in the dimensionless form are discretized via finite volume method. The velocity–pressure coupling is assured by the SIMPLE algorithm. Heat transfer balance is used to verify the convergence. The validation of the numerical results was performed by comparing qualitatively and quantitatively the results with previously published investigations. Findings The results indicate that the magnetic field and the conductivity ratio of the wavy solid block can significantly affect the dynamic and thermal field and, consequently, the heat transfer rate and entropy generation because of heat transfer, fluid friction and magnetic force. Originality/value To the best of the authors’ knowledge, the present numerical study is the first attempt to use hybrid nanofluid for studying the entropy generation because of magnetohydrodynamic natural convective flow in a square cavity with the presence of a wavy circular conductive cylinder. Irreversibilities due to magnetic effect are taken into account. The effect of fluid–solid thermal conductivity ratio is considered.

Chemical reaction effectiveness in non-Darcian nanofluid radiated flow considering entropy generation

2019 ◽  
Vol 29 (9) ◽  
pp. 3535-3556 ◽  
Author(s):  
M.Z. Kiyani ◽  
Tasawar Hayat ◽  
I. Ahmad ◽  
Ahmed Alsaedi
Keyword(s):  
Porous Medium ◽  
Mixed Convection ◽  
Entropy Production ◽  
Entropy Generation ◽  
Magnetic Permeability ◽  
Design Methodology ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Content Type ◽  
Carreau Nanofluid

Purpose The purpose of this study is to analyze the entropy generation in magnetohydrodynamics stagnation point mixed convection flow of Carreau nanofluid through porous medium. Design/methodology/approach The system is solved using the homotopy scheme. Findings Minimizing radiation, magnetic, permeability and temperature difference parameters responds to minimizing entropy production. Originality/value To the best of the authors’ knowledge, no such analysis has yet been reported.

Entropy generation and heat transport of Cu–water nanoliquid in porous lid-driven cavity through magnetic field

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Souad Marzougui ◽  
Fateh Mebarek-Oudina ◽  
Mourad Magherbi ◽  
Ali Mchirgui
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Heat Transport ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Total Entropy ◽  
Magnetic Field Effects ◽  
Content Type ◽  
Driven Cavity ◽  
Porous Enclosure

Purpose The purpose of this paper is to investigate the effects of Ha and the Nanoparticles (NP) volume fraction over the irreversibility and heat transport in Darcy–Forchheimer nanofluid saturated lid-driven porous medium. Design/methodology/approach The present paper highlights entropy generation because of mixed convection for a lid-driven porous enclosure filled through a nanoliquid and submitted to a uniform magnetic field. The analysis is achieved using Darcy–Brinkman–Forchheimer technique. The set of partial differential equations governing the considered system was numerically solved using the finite element method. Findings The main observations are as follows. The results indicate that the movement of horizontal wall is an important factor for the entropy generation inside the porous cavity filled through Cu–water nanoliquid. The variation of the thermal entropy generation is linear through NPs volume fraction. The total entropy generation reduces when the Darcy, Hartmann and the nanoparticle volume fraction increase. The porous media and magnetic field effects reduce the total entropy generation. Practical implications Interest in studying thermal interactions by convective flow within a saturating porous medium has many fundamental considerations and has received extensive consideration in the literature because of its usefulness in a large variety of engineering applications, such as the energy storage and solar collectors, crystal growth, food processing, nuclear reactors and cooling of electronic devices, etc. Originality/value By examining the literature, the authors found that little attention has been paid to entropy generation encountered during convection of nanofluids. Hence, this work aims to numerically study entropy generation and heat transport in a lid-driven porous enclosure filled with a nanoliquid.

Entropy generation optimization for MHD natural convection of a nanofluid in porous media-filled enclosure with active parts and viscous dissipation

2017 ◽  
Vol 27 (2) ◽  
pp. 379-399 ◽  
Author(s):  
M.A. Mansour ◽  
Sameh Elsayed Ahmed ◽  
Ali J. Chamkha
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Convection Flow ◽  
Negative Effects ◽  
Content Type ◽  
Volume Method

Purpose This paper aims to investigate the entropy generation due to magnetohydrodynamic natural convection flow and heat transfer in a porous enclosure filled with Cu-water nanofluid in the presence of viscous dissipation effect. The left and right walls of the cavity are thermally insulated. There are heated and cold parts, and these are placed on the bottom and top wall, respectively, whereas the remaining parts are thermally insulated. Design/methodology/approach The finite volume method is used to solve the dimensionless partial differential equations governing the problem. A comparison with previously published woks is presented and is found to be in an excellent agreement. Findings The minimization of entropy generation and local heat transfer according to different values of the governing parameters are presented in details. It is found that the presence of magnetic field has negative effects on the local entropy generation because of heat transfer and the local total entropy generation. Also, the increase in the heated part length leads to a decrease in the local Nusselt number. Originality/value This problem is original, as it has not been considered previously.

Heat and mass transfer effects on MHD non-Newtonian fluids flow through an inclined thermally-stratified porous medium

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gladys Tharapatla ◽  
Pamula Rajakumari ◽  
Ramana G.V. Reddy
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Velocity Profile ◽  
Heat And Mass Transfer ◽  
Newtonian Fluids ◽  
Transfer Effects ◽  
Content Type ◽  
Non Linear ◽  
Homotopy Analysis ◽  
Flow Through

Purpose This paper aims to analyze heat and mass transfer of magnetohydrodynamic (MHD) non-Newtonian fluids flow past an inclined thermally stratified porous plate using a numerical approach. Design/methodology/approach The flow equations are set up with the non-linear free convective term, thermal radiation, nanofluids and Soret–Dufour effects. Thus, the non-linear partial differential equations of the flow analysis were simplified by using similarity transformation to obtain non-linear coupled equations. The set of simplified equations are solved by using the spectral homotopy analysis method (SHAM) and the spectral relaxation method (SRM). SHAM uses the approach of Chebyshev pseudospectral alongside the homotopy analysis. The SRM uses the concept of Gauss-Seidel techniques to the linear system of equations. Findings Findings revealed that a large value of the non-linear convective parameters for both temperature and concentration increases the velocity profile. A large value of the Williamson term is detected to elevate the velocity plot, whereas the Casson parameter degenerates the velocity profile. The thermal radiation was found to elevate both velocity and temperature as its value increases. The imposed magnetic field was found to slow down the fluid velocity by originating the Lorentz force. Originality/value The novelty of this paper is to explore the heat and mass transfer effects on MHD non-Newtonian fluids flow through an inclined thermally-stratified porous medium. The model is formulated in an inclined plate and embedded in a thermally-stratified porous medium which to the best of the knowledge has not been explored before in literature. Two elegance spectral numerical techniques have been used in solving the modeled equations. Both SRM and SHAM were found to be accurate.

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