scholarly journals Entropy Generation and Natural Convection Flow of Hybrid Nanofluids in a Partially Divided Wavy Cavity Including Solid Blocks

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2942 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Ishak Hashim ◽  
Ahmad Hajjar ◽  
Mohammad Ghalambaz ◽  
Sohail Nadeem ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Convection Flow ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Hybrid Nanofluids ◽  
Wavy Cavity ◽  
Rayleigh Numbers

The present investigation addressed the entropy generation, fluid flow, and heat transfer regarding Cu-Al 2 O 3 -water hybrid nanofluids into a complex shape enclosure containing a hot-half partition were addressed. The sidewalls of the enclosure are made of wavy walls including cold isothermal temperature while the upper and lower surfaces remain insulated. The governing equations toward conservation of mass, momentum, and energy were introduced into the form of partial differential equations. The second law of thermodynamic was written for the friction and thermal entropy productions as a function of velocity and temperatures. The governing equations occurred molded into a non-dimensional pattern and explained through the finite element method. Outcomes were investigated for Cu-water, Al 2 O 3 -water, and Cu-Al 2 O 3 -water nanofluids to address the effect of using composite nanoparticles toward the flow and temperature patterns and entropy generation. Findings show that using hybrid nanofluid improves the Nusselt number compared to simple nanofluids. In the case of low Rayleigh numbers, such enhancement is more evident. Changing the geometrical aspects of the cavity induces different effects toward the entropy generation and Bejan number. Generally, the global entropy generation for Cu-Al 2 O 3 -water hybrid nanofluid takes places between the entropy generation values regarding Cu-water and Al 2 O 3 -water nanofluids.

MHD Flow of Cu-Al2O3/Water Hybrid Nanofluid in Porous Channel: Analysis of Entropy Generation

2017 ◽  
Vol 377 ◽  
pp. 42-61 ◽  
Author(s):  
Sanatan Das ◽  
Rabindra Nath Jana ◽  
Oluwole Daniel Makinde
Keyword(s):  
Entropy Generation ◽  
Mhd Flow ◽  
Transverse Magnetic ◽  
Porous Channel ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Governing Equations ◽  
Transfer Enhancement ◽  
Entropy Generation Number ◽  
Channel Analysis

In this investigation, a magnetohydrodynamic (MHD) flow of AlO /water nanofluid and Cu-AlO /water hybrid nanofluid through a porous channel is analyzed in the presence of a transverse magnetic field. An exact solution of the governing equations has been obtained in closed form. The entropy generation number and the Bejan number are also obtained. The influences of each of the governing parameters on velocity, temperature, entropy generation and Bejan number are displayed graphically and the physical aspects are discussed. In addition, a comparison of the heat transfer enhancement level due to the suspension of AlO and Cu nanoparticles in water as regular nanofluids and as hybrid Cu-AlO /water nanofluid is reported.

Comparative analysis of (Zinc ferrite, Nickel Zinc ferrite) hybrid nanofluids slip flow with entropy generation

2021 ◽  
pp. 2150342
Author(s):  
P.-Y. Xiong ◽  
M. Ijaz Khan ◽  
R. J. Punith Gowda ◽  
R. Naveen Kumar ◽  
B. C. Prasannakumara ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Zinc Ferrite ◽  
Slip Flow ◽  
Engine Oil ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Nonlinear Thermal Radiation ◽  
Lower Velocity ◽  
Nickel Zinc ◽  
Hybrid Nanofluids

This investigation is about hybrid nanofluid flowing over a sheet. We considered two-dimensional Darcy–Forchheimer flow of different hybrid nanofluids with the influence of uniform heat source sink and nonlinear thermal radiation. Different nanoparticles can be used to improve the thermal conductivity of a liquid. A study comparing the various hybrid nanofluids to nanofluid is considered. Here, we have selected manganese Zinc ferrite and Nickel Zinc ferrite as nanoparticles with kerosene oil and engine oil as carrier liquids. Suitable similarity transformations are used to construct the required ordinary differential equations. The influence of several non-dimensional parameters on velocity and thermal gradients is analyzed through graphs. Also, entropy generation is computed and analyzed through graph for different involved parameters. Here, we observed that [Formula: see text]–[Formula: see text]–[Formula: see text]–[Formula: see text] had lower velocity when compared to other two solutions. The entropy generation and Bejan number are high in [Formula: see text]–[Formula: see text]–[Formula: see text] when compared to [Formula: see text]–[Formula: see text]–[Formula: see text]–[Formula: see text] and [Formula: see text]–[Formula: see text]–[Formula: see text] and increase in heat generation parameter increases the rate of heat transfer.

scholarly journals Free Convection Heat Transfer and Entropy Generation in an Odd-Shaped Cavity Filled with a Cu-Al2O3 Hybrid Nanofluid

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 122
Author(s):  
Mohammad Ghalambaz ◽  
Seyed Mohsen Hashem Zadeh ◽  
Ali Veismoradi ◽  
Mikhail A. Sheremet ◽  
Ioan Pop
Keyword(s):  
Heat Transport ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Hybrid Nanoparticles ◽  
Width Ratio ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Nanoparticles Concentration ◽  
Rayleigh Numbers

The present paper aims to analyze the thermal convective heat transport and generated irreversibility of water-Cu-Al2O3 hybrid nanosuspension in an odd-shaped cavity. The side walls are adiabatic, and the internal and external borders of the enclosure are isothermally kept at high and low temperatures of Thand Tc, respectively. The control equations based on conservation laws are formulated in dimensionless form and worked out employing the Galerkin finite element technique. The outcomes are demonstrated using streamlines, isothermal lines, heatlines, isolines of Bejan number, as well as the rate of generated entropy and the Nusselt number. Impacts of the Rayleigh number, the hybrid nanoparticles concentration (ϕhnf), the volume fraction of the Cu nanoparticles to ϕhnf ratio (ϕr), width ratio (WR) have been surveyed and discussed. The results show that, for all magnitudes of Rayleigh numbers, increasing nanoparticles concentration intensifies the rate of entropy generation. Moreover, for high Rayleigh numbers, increasing WR enhances the rate of heat transport.

scholarly journals Entropy generation due to the mixed convection flow of MWCNT−MgO/water hybrid nanofluid in a vented complex shape cavity

2020 ◽  
Vol 307 ◽  
pp. 01007
Author(s):  
Mahdi Benzema ◽  
Youb Khaled Benkahla ◽  
Ahlem Boudiaf ◽  
Seif-Eddine Ouyahia ◽  
Mohammed El Ganaoui
Keyword(s):  
Mixed Convection ◽  
Entropy Generation ◽  
Complex Shape ◽  
Volume Fraction ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Convection Flow ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Inclined Plate

This paper reports a numerical study of mixed convection heat transfer with entropy generation in a vented complex shape cavity filled with MWCNT−MgO (15:85 vol %) /water hybrid nanofluid. A hot source is placed at the mid potion of the inclined plate of the enclosure, while the rest of the rigid walls are adiabatic. A thermo-dependent correlations proposed by [12] for the dynamic viscosity and the thermal conductivity, especially developed for the considered fluid, are used. After validation of the model, the analysis has been done for a Reynolds numbers ranging from 10 to 600 and total nanoparticles volume fraction ranging from 0.0 to 0.02 using the finite volume method. The predicted results of streamlines, isotherms, isentropic lines, average Nusselt number, average entropy generation and average Bejan number are the main focus of interest in the present paper.

scholarly journals Thermal Non-Equilibrium Heat Transfer Modeling of Hybrid Nanofluids in a Structure Composed of the Layers of Solid and Porous Media and Free Nanofluids

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 541 ◽  
Author(s):  
Ali J. Chamkha ◽  
Sina Sazegar ◽  
Esmael Jamesahar ◽  
Mohammad Ghalambaz
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Conjugate Heat Transfer ◽  
Hybrid Nanofluid ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Clear Space ◽  
Hybrid Nanofluids ◽  
Solid Block ◽  
Non Equilibrium

The free convection heat transfer of hybrid nanofluids in a cavity space composed of a clear flow, porous medium and a solid part is addressed. The cavity is heated from the bottom and cooled from the top. The side walls are well insulated. The upper part of the cavity is a clear space with no porous or solid materials and is filled with hybrid nanofluid. The bottom part is divided into two parts of a porous space saturated with the hybrid nanofluid and a solid thermal conductive block. There are conjugate heat transfer mechanisms between the solid block and the porous medium filled with the hybrid nanofluid as well as the hybrid nanofluid in the clear space. For the porous medium model, the local thermal non-equilibrium effects are considered. The hybrid nanofluids contain copper (20 nm) and alumina nanoparticles (40 nm) hybrid nanoparticles. The governing equations for the flow and heat transfer of the hybrid nanofluid in the clear space and the porous medium are introduced. Considering the conjugate heat transfer between the solid block and the hybrid nanofluid fluid in the pores and the porous matrix, appropriate boundary conditions for heat channeling are utilized. The governing equations are transformed into non-dimensional form to generalize the model. The finite element method is employed to solve the equations. The grid check and validation procedure are performed. Subsequently streamlines, isotherms, and Nusselt number are studied as important aspects of flow and heat transfer in the cavity. The increase in the portion of the clear flow part in the cavity enhances heat transfer due to better hybrid nanofluid circulation.

scholarly journals Generalization of the Convective Flow of Brinkman-Type Fluid Using Fourier’s and Fick’s Laws: Exact Solutions and Entropy Generation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Nadeem Ahmad Sheikh ◽  
Dennis Ling Chuan Ching ◽  
Ilyas Khan ◽  
Hamzah bin Sakidin
Keyword(s):  
Entropy Generation ◽  
Mass Concentration ◽  
Special Function ◽  
Time Parameter ◽  
Convection Flow ◽  
Bejan Number ◽  
Governing Equations ◽  
Free Convection Flow ◽  
Fluid Parameter ◽  
The Given

A new scheme to formulating the Caputo time-fractional model for the flow of Brinkman-type fluid between the plates was introduced by using the generalized laws of Fourier and Fick. Within a channel, free convection flow of the electrically conducted Brinkman-type fluid was considered. A newly generated transformation was applied to the heat and mass concentration equations. The governing equations were solved by the techniques of Fourier sine and the Laplace transforms. In terms of the special function, namely, the Mittag-Leffler function, final solutions were obtained. The entropy generation and Bejan number are also calculated for the given flow. To explain the conceptual arguments of the embedded parameters, separate plots are represented in figures and are often quantitatively computed and presented in tables. It is worth noting that for increasing the values of the Brinkman-type fluid parameter, the velocity profile decreases. The regression analysis shows that the variation in the velocity for time parameter is statistically significant.

scholarly journals Fully Developed Opposing Mixed Convection Flow in the Inclined Channel Filled with a Hybrid Nanofluid

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1107
Author(s):  
Xiangcheng You ◽  
Shiyuan Li
Keyword(s):  
Flow Reversal ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Hybrid Nanofluid ◽  
Type Ii ◽  
Inclined Channel ◽  
Volume Fractions ◽  
Type Iii ◽  
Hybrid Nanofluids ◽  
Temperature And Pressure

This paper studies the convective heat transfer of a hybrid nanofluid in the inclined channel, whose walls are both heated by the uniform heat flux. The governing ordinary differential equations are made nondimensional and solved analytically, in which explicit distributions of velocity, temperature and pressure are obtained. The effects of flow reversal, wall skin friction and Nusselt number with the hybrid nanofluid depend on the nanoparticle volume fractions and pressure parameters. The obtained results indicate that the nanoparticle volume fractions play a key role in delaying the occurrence of the flow reversal. The hybrid nanofluids hold more delayed range than conventional nanofluids, which is about 2.5 times that of nanofluids. The calculations have been compared with the base fluid, nanofluid and two kinds of hybrid models (type II and type III). The hybrid model of type III is useful and simplified in that it omits the nonlinear terms due to the interaction of different nanoparticle volumetric fractions, with the relative error less than 3%. More results are discussed in the results section below.

Transient Natural Convection Between Two Zones in an Insulated Enclosure

1988 ◽  
Vol 110 (1) ◽  
pp. 116-125 ◽  
Author(s):  
P. A. Litsek ◽  
A. Bejan
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Experiments ◽  
Thermal Stratification ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Flow And Heat Transfer ◽  
Vertical Opening ◽  
The Right ◽  
Rayleigh Numbers

The natural convection flow and heat transfer between two enclosures that communicate through a vertical opening is studied by considering the evolution of an enclosed fluid in which the left half is originally at a different temperature than the right half. Numerical experiments show that at sufficiently high Rayleigh numbers the ensuing flow is oscillatory. This and other features are anticipated on the basis of scale analysis. The time scales of the oscillation, the establishment of thermal stratification, and eventual thermal equilibrium are determined and tested numerically. At sufficiently high Rayleigh numbers the heat transfer between the communicating zones is by convection, in accordance with the constant-Stanton-number trend pointed out by Jones and Otis (1986). The range covered by the numerical experiments is 102 < Ra < 107, 0.71 < Pr < 100, and 0.25 < H/L < 1.

scholarly journals Free convection heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a porous complex shaped cavity with MHD and thermal radiation effects

2019 ◽  
Vol 29 (11) ◽  
pp. 4349-4376 ◽  
Author(s):  
Mohammad Ghalambaz ◽  
Mahmoud Sabour ◽  
Ioan Pop ◽  
Dongsheng Wen
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Porous Medium ◽  
Complex Shape ◽  
Convection Heat Transfer ◽  
Hybrid Nanofluid ◽  
Convection Heat ◽  
Governing Equations ◽  
Content Type ◽  
Hybrid Nanofluids

Purpose The present study aims to address the flow and heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a complex shape enclosure filled with a porous medium. The enclosure is subject to a uniform inclined magnetic field and radiation effects. The effect of the presence of a variable magnetic field on the natural convection heat transfer of hybrid nanofluids in a complex shape cavity is studied for the first time. The geometry of the cavity is an annular space with an isothermal wavy outer cold wall. Two types of the porous medium, glass ball and aluminum metal foam, are adopted for the porous space. The governing equations for mass, momentum and heat transfer of the hybrid nanofluid are introduced and transformed into non-dimensional form. The actual available thermal conductivity and dynamic viscosity data for the hybrid nanofluid are directly used for thermophysical properties of the hybrid nanofluid. Design/methodology/approach The governing equations for mass, momentum and heat transfer of hybrid nanofluid are introduced and transformed into non-dimensional form. The thermal conductivity and dynamic viscosity of the nanofluid are directly used from the experimental results available in the literature. The finite element method is used to solve the governing equations. Grid check procedure and validations were performed. Findings The effect of Hartmann number, Rayleigh number, Darcy number, the shape of the cavity and the type of porous medium on the thermal performance of the cavity are studied. The outcomes show that using the composite nanoparticles boosts the convective heat transfer. However, the rise of the volume fraction of nanoparticles would reduce the overall enhancement. Considering a convective dominant regime of natural convection flow with Rayleigh number of 107, the maximum enhancement ratio (Nusselt number ratio compared to the pure fluid) for the case of glass ball is about 1.17 and for the case of aluminum metal foam is about 1.15 when the volume fraction of hybrid nanoparticles is minimum as 0.2 per cent. Originality/value The effect of the presence of a variable magnetic field on the natural convection heat transfer of a new type of hybrid nanofluids, MgO-MWCNTs/EG, in a complex shape cavity is studied for the first time. The results of this paper are new and original with many practical applications of hybrid nanofluids in the modern industry.

scholarly journals Numerical Investigation of Entropy Generation in Unsteady MHD Generalized Couette Flow with Variable Electrical Conductivity

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
T. Chinyoka ◽  
O. D. Makinde
Keyword(s):  
Electrical Conductivity ◽  
Couette Flow ◽  
Entropy Generation ◽  
Fluid Velocity ◽  
Bejan Number ◽  
Governing Equations ◽  
Entropy Generation Number ◽  
Thermophysical Parameters ◽  
Second Law Analysis ◽  
Finite Difference Techniques

The thermodynamic second law analysis is utilized to investigate the inherent irreversibility in an unsteady hydromagnetic generalized Couette flow with variable electrical conductivity in the presence of induced electric field. Based on some simplified assumption, the model nonlinear governing equations are obtained and solved numerically using semidiscretization finite difference techniques. Effects of various thermophysical parameters on the fluid velocity, temperature, current density, skin friction, the Nusselt number, entropy generation number, and the Bejan number are presented graphically and discussed quantitatively.

Sign in / Sign up

Export Citation Format

Share Document