Irreversibility analysis in squeezing nanofluid flow with thermal radiation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
T. Hayat ◽  
M. Waqar Ahmad ◽  
Sohail Ahamd Khan ◽  
Ahmed Alsaedi
Keyword(s):  
Entropy Generation ◽  
Brownian Diffusion ◽  
Squeezing Flow ◽  
Bejan Number ◽  
Porous Space ◽  
Content Type ◽  
Conductivity Enhancement ◽  
Diffusion Parameters ◽  
Analysis Technique ◽  
Homotopy Analysis

PurposeMagnetohydrodynamic (MHD) nanoliquid are significant for thermal conductivity enhancement. The examination of heat transfer of crushing time-subordinate liquid flow past isometric surfaces has throughout the decades been a field of consideration for its wide scope of physical necessities: nourishment preparation, pressure, grease setup and hydrodynamic machines. Entropy generation in the squeezing flow of viscous nanomaterial is developed. MHD, Brownian motion and thermophoresis are considered. Porous space between the disks is taken. The analysis is carried out in the presence of radiation and viscous dissipation.Design/methodology/approachNonlinear systems are reduced to an ordinary one through similarity variables. The convergent solution is developed by employing the homotopy analysis technique (HAM).FindingsConvergent homotopic solutions are developed for the velocity, temperature and concentration. Entropy generation and Bejan number are explained. Skin friction and Nusselt number and Sherwood number are analyzed. For a higher approximation of porosity, parameter velocity is augmented. Temperature upsurges for larger thermophoresis and Brownian diffusion parameters. Concentration has an increasing effect on thermophoresis and Brownian diffusion parameters. For the rising value of the radiation parameter, both the Bejan number and entropy rate have increasing behaviors.Originality/valueNo such work is yet published in the literature.

Computational analysis of nanofluid and hybrid nanofluid in Darcy’s squeezing flow with entropy optimization

2019 ◽  
Vol 29 (9) ◽  
pp. 3394-3416 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
Ahmed Alsaedi ◽  
Salman Ahmad ◽  
Tasawar Hayat
Keyword(s):  
Skin Friction ◽  
Entropy Generation ◽  
Variable Temperature ◽  
Entropy Generation Rate ◽  
Squeezing Flow ◽  
Hybrid Nanofluid ◽  
Bejan Number ◽  
Porous Space ◽  
Suction Parameter ◽  
Content Type

Purpose This paper aims to examine squeezing flow of hybrid nanofluid inside the two parallel rotating sheets. The upper sheet squeezes downward, whereas the lower sheet stretches. Darcy’s relation describes porous space. Hybrid nanofluid consists of copper (Cu) and titanium oxide (TiO2) nanoparticles and water (H2O). Viscous dissipation and thermal radiation in modeling are entertained. Entropy generation analysis is examined. Design/methodology/approach Transformation procedure is implemented for conversion of partial differential systems into an ordinary one. The shooting scheme computes numerical solution. Findings Velocity, temperature, Bejan number, entropy generation rate, skin friction and Nusselt number are discussed. Key results are mentioned. Velocity field increases vs higher estimations of squeezing parameter, while it declines via larger porosity variable. Temperature of liquid particles enhances vs larger Eckert number. It is also examined that temperature field dominates for TiO2-H2O, Cu-H2O and Cu-TiO2-H2O. Magnitude of heat transfer rate and skin friction coefficient increase against higher squeezing parameter, radiative parameter, porosity variable and suction parameter. Originality/value The originality of this paper is investigation of three-dimensional time-dependent squeezing flow of hybrid nanomaterial between two parallel sheets. To the best of the authors’ knowledge, no such consideration has been carried out in the literature.

Analysis of entropy generation in an inclined channel flow containing two immiscible micropolar fluids using HAM

2016 ◽  
Vol 26 (3/4) ◽  
pp. 1027-1049 ◽  
Author(s):  
J. Srinivas ◽  
J.V. Ramana Murthy ◽  
Ali J Chamkha
Keyword(s):  
Entropy Generation ◽  
Flow Region ◽  
Flow Equation ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Bejan Number ◽  
Micropolar Fluids ◽  
Content Type ◽  
Inclined Channel ◽  
Homotopy Analysis

Purpose – The purpose of this paper is to examine the flow, heat transfer and entropy generation characteristics for an inclined channel of two immiscible micropolar fluids. Design/methodology/approach – The flow region consists of two zones, the flow of the heavier fluid taking place in the lower zone. The flow is assumed to be governed by Eringen’s micropolar fluid flow equation. The resulting governing equations are then solved using the homotopy analysis method. Findings – The following findings are concluded: first, the entropy generation rate is more near the plates in both the zones as compared to that of the interface. This indicates that the friction due to surface on the fluids increases entropy generation rate. Second, the entropy generation rate is more near the plate in Zone I than that of Zone II. This may be due to the fact that the fluid in Zone I is more viscous. This indicates the more the viscosity of the fluid is, the more the entropy generation. Third, Bejan number is the maximum at the interface of the fluids. This indicates that the amount of exergy (available energy) is maximum and irreversibility is minimized at the interface between the fluids. Fourth, as micropolarity increases, entropy generation rate near the plates decreases and irreversibility decreases. This indicates an important industrial application for micropolar fluids to use them as a good lubricant. Originality/value – The problem is original as no work has been reported on entropy generation in an inclined channel with two immiscible micropolar fluids.

Irreversibility and Thermo-Diffusion Effects on Unsteady Chemically Reactive Slip Flow Between Two Rotating Disks

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
M. Ijaz Khan ◽  
Sumaira Qayyum ◽  
T. Hayat ◽  
M. Waqas ◽  
A. Alsaedi
Keyword(s):  
Slip Flow ◽  
Velocity Slip ◽  
Convergent Series ◽  
Heterogeneous Reactions ◽  
Bejan Number ◽  
Nonlinear Thermal Radiation ◽  
Slip Parameter ◽  
Rotating Disks ◽  
Diffusion Parameters ◽  
Homotopy Analysis

Abstract This paper aims to investigate the entropy generation in slip flow due to double rotating disks. Heat equation is formulated by considering effects of viscous dissipation, Joule heating and nonlinear thermal radiation. Brownian motion and thermophoresis effects of nanofluid are also discussed. Applied magnetic field is considered to be time dependent. Homogeneous–heterogeneous reactions are also studied. Von Karman transformations are used. Homotopy analysis method is implemented on system of equations for convergent series solutions. Influence of various flow parameters on entropy, Bejan number, velocity, temperature, Nusselt number, and skin friction is discussed through graphs and tables. Axial velocity decays for higher nonlinear mixed convection variable of temperature and velocity slip parameter. Temperature rises for larger thermal slip parameter and thermophoresis parameter. Entropy and Bejan number are increasing for higher estimation of homogeneous reaction parameter and diffusion parameters.

scholarly journals Entropy Generation and Consequences of Binary Chemical Reaction on MHD Darcy–Forchheimer Williamson Nanofluid Flow Over Non-Linearly Stretching Surface

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 18 ◽  
Author(s):  
Ghulam Rasool ◽  
Ting Zhang ◽  
Ali J. Chamkha ◽  
Anum Shafiq ◽  
Iskander Tlili ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Second Law Of Thermodynamics ◽  
Magnetic Reynolds Number ◽  
Random Motion ◽  
Weissenberg Number ◽  
Brownian Diffusion ◽  
Bejan Number ◽  
Nanofluid Flow ◽  
Highly Nonlinear ◽  
Buongiorno Model

The current article aims to present a numerical analysis of MHD Williamson nanofluid flow maintained to flow through porous medium bounded by a non-linearly stretching flat surface. The second law of thermodynamics was applied to analyze the fluid flow, heat and mass transport as well as the aspects of entropy generation using Buongiorno model. Thermophoresis and Brownian diffusion is considered which appears due to the concentration and random motion of nanoparticles in base fluid, respectively. Uniform magnetic effect is induced but the assumption of tiny magnetic Reynolds number results in zero magnetic induction. The governing equations (PDEs) are transformed into ordinary differential equations (ODEs) using appropriately adjusted transformations. The numerical method is used for solving the so-formulated highly nonlinear problem. The graphical presentation of results highlights that the heat flux receives enhancement for augmented Brownian diffusion. The Bejan number is found to be increasing with a larger Weissenberg number. The tabulated results for skin-friction, Nusselt number and Sherwood number are given. A decent agreement is noted in the results when compared with previously published literature on Williamson nanofluids.

Comprehensive hydrothermal analysis of an inclined mini-channel with fin array: by dual/multi-relaxation-time LBM and experimental process on SiO2-glycol rheological/thermal characteristics

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Daryoush Kamali ◽  
Saeid Hejri ◽  
Narges Akbar ◽  
Emad Hasani Malekshah
Keyword(s):  
Relaxation Time ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Thermal Characteristics ◽  
Lattice Models ◽  
Temperature Fields ◽  
Bejan Number ◽  
Maximum Enhancement ◽  
Content Type ◽  
Structure Of Flow

Purpose The purpose of this study is to present a comprehensive hydrothermal analysis on an inclined mini-channel using numerical and experimental techniques. The fin array acts as heat source within the channel, and a wavy wall located at the top of the channel is heat sink. The side walls are insulated with curved profiles. Also, the channel is inclined with four known inclination angles. To solve the governing equations, the dual-multi-relaxation-time lattice Boltzmann method with D2Q9 and D2Q5 lattice models for flow and temperature fields is used, respectively. Also, the channel is filled with SiO2-glycol nanofluid. Design/methodology/approach Identifying the behavior of a thermal component during natural convective flow is a challenging topic due to its complexities. This paper focuses on analyzing the thermal and hydrodynamic aspects of a narrow channel equipping with fin array. Findings Two correlations are proposed considering temperature and volume fraction ranges for thermal conductivity and dynamic viscosity according to measured experimental data which are used in the numerical phase. Finally, the structure of flow, temperature distribution of fluid, local thermal and viscous dissipations, volume-averaged entropy production, Bejan number and heat transfer rate are extracted by numerical simulations. The results show that the average Nusselt number enhances about 57% (maximum enhancement percentage) when volume fraction increases from 1% to 3% at Ra = 106 and θ = 90°. In addition, the value of entropy generation is maximum at φ = 1%, Ra = 106 and φ = 90°. Also, the maximum enhancement of entropy generation in range of Ra = 103 to 106 is about 4 times at φ = 1% and θ = 90°. Originality/value The originality of the present study is combining a modern numerical method (i.e. dual/multi-relaxation-time LBM) with experimental observation on characteristics of SiO2-glycol nanofluid to study the thermal and hydrodynamic properties of the studied mini-channel.

Entropy generation and thermo-diffusion effects on unsteady chemically reactive slip flow between two rotating disks

2019 ◽  
Vol 29 (10) ◽  
pp. 3795-3821
Author(s):  
Sumaira Qayyum ◽  
Muhammad Ijaz Khan ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi
Keyword(s):  
Magnetic Field ◽  
Entropy Generation ◽  
Stokes Equations ◽  
Tangential Velocity ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Bejan Number ◽  
Thermal Equation ◽  
Content Type ◽  
Flow Variables

Purpose The purpose of this study is to analyze the Entropy generation analysis and heat transport in three-dimensional flow between two stretchable disks. Joule heating and heat generation/absorption are incorporated in the thermal equation. Thermo-diffusion effect is also considered. Flow is conducting for time-dependent applied magnetic field. Induced magnetic field is not taken into consideration. Velocity and thermal slip conditions at both the disks are implemented. The flow problem is modeled by using Navier–Stokes equations with entropy generation rate and Bejan number. Design/methodology/approach Von Karman transformations are used to reduce the nonlinear governing expressions into an ordinary one and then tackled by homotopy analysis method for convergent series solutions. The nonlinear expressions for total entropy generation rate are obtained with appropriate transformations. The impacts of different flow variables on velocity, temperature, entropy generation rate and Bejan number are described graphically. Velocity, temperature and concentration gradients are discussed in the presence of flow variables. Findings Axial, radial and tangential velocity profiles show decreasing trend for larger values of velocity slip parameters. For a larger Brinkman number, the entropy generation increases, while a decreasing trend is noticed for Bejan number. Originality/value To the best of the authors’ knowledge, no such analyses have been reported in the literature.

Entropy generation in radiative flow of Ree-Eyring fluid due to due rotating disks

2019 ◽  
Vol 29 (6) ◽  
pp. 2057-2079 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
Sohail Ahmad Khan ◽  
Tasawar Hayat ◽  
Muhammad Faisal Javed ◽  
Ahmed Alsaedi
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Magnetic Parameter ◽  
Nonlinear Flow ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Bejan Number ◽  
Rotating Disks ◽  
Content Type ◽  
The Impact

Purpose This study aims to examine the flow characteristics of Ree–Eyring fluid between two rotating disks. The characteristics of heat transfer are discussed in presence of viscous dissipation, heat source/sink and nonlinear radiative heat flux. Design/methodology/approach Nonlinear flow expressions lead to ordinary ones through adequate similarity transformations. The ordinary differential system has been tackled through optimal homotopic method. The impact of different flow variables on the velocity field, entropy generation rate and temperature fields is graphically discussed. The surface drag force and heat transfer rate are numerically examined via various pertinent parameters. Findings By minimization of values of stretching parameter and Brinkman number, the entropy generation rate can be controlled. The entropy generation rate enhances for higher values of magnetic parameter, while the Bejan number is decreased via magnetic parameter. Originality/value No such work is yet published in the literature.

Physical aspects of magnetized Jeffrey nanomaterial flow with irreversibility analysis

2021 ◽  
Author(s):  
Fazal Haq ◽  
Muhammad Ijaz Khan ◽  
Sami Ullah Khan ◽  
Khadijah M. Abualnaja ◽  
M. A. El-Shorbagy
Keyword(s):  
Differential Equations ◽  
Entropy Generation ◽  
Nonlinear Differential Equations ◽  
Transportation Systems ◽  
Physical Parameters ◽  
Bejan Number ◽  
Convective Boundary ◽  
Homotopy Analysis ◽  
Permeability Parameter ◽  
Thermal Features

Abstract This analysis presents the applications of entropy generation phenomenon in incompressible flow of Jeffrey nanofluid in presence of distinct thermal features. The novel aspects of various features like Joule heating, porous medium, dissipation features and radiative mechanism is addressed. In order to improve the thermal transportation systems based on nanomaterials, the convective boundary conditions are introduced. The thermal viscoelastic nanofluid model is expressed in term of differential equations. The problem is presented via nonlinear differential equations for which analytical expressions are obtained by using homotopy analysis method(HAM). The accuracy of solution is ensured. The effective outcomes of all physical parameters associated with the flow model are carefully examined and underlined through various curves. The observations summarized from current analysis reveal that presence of permeability parameter offers resistance to the flow. A monotonic decrement in local Nusselt number is noted with Hartmann number and Prandtl number. Moreover, entropy generation and Bejan number increases with radiation parameter and fluid parameter.

Entropy analysis of Poiseuille nanofluid flow in a porous channel with slip and convective boundary conditions under magnetic field

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
S. Das ◽  
S. Chakraborty ◽  
R. N. Jana
Keyword(s):  
Magnetic Field ◽  
Entropy Generation ◽  
Poiseuille Flow ◽  
Magnetic Parameter ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Convective Heating ◽  
Bejan Number ◽  
Content Type ◽  
Hydrodynamic Slip

Purpose This study aims to expose the flow phenomena and entropy generation during a; magnetohydrodynamic (MHD) Poiseuille flow of water-based nanofluids (NFs) in a porous channel subject to hydrodynamic slip and convective heating boundary conditions. The flow caused by the uniform pressure; gradient between infinite parallel plates is considered steady and fully developed. The nanoparticles; namely, copper, alumina and titanium oxide are taken with pure water as the base fluid. Viscous dissipation and Joule heating impacts are also incorporated in this investigation. Design/methodology/approach The reduced governing equations are solved analytically in closed form. The physical insights of noteworthy parameters on the important flow quantities are demonstrated through graphs and analyzed elaborately. The thermodynamic analysis is performed by calculating entropy generation; rate and Bejan number. A graphical comparison between solutions corresponding to NFs and regular fluid in the channel is also provided. Findings The analysis of the results divulges that entropy generation minimization can be achieved by an appropriate combination of the geometrical and physical parameters of thermomechanical systems. It is reported that ascent in magnetic parameter number declines the velocity profiles, while the inverse pattern is witnessed with augmentation in hydrodynamic slip parameters. The temperature dissemination declines with the growth of Biot numbers. It is perceived that the entropy generation rate lessens with an upgrade in magnetic parameter, whereas the reverse trend of Bejan number is perceived with expansion in magnetic parameter and Biot number. The important contribution of the result is that the entropy generation rate is controlled with an appropriate composition of thermo-physical parameter values. Moreover, in the presence of a magnetic field and suction/injection at the channel walls, the shear stresses at the channel walls are reduced about two times. Practical implications In various industrial applications, minimizing entropy generation plays a significant role. Miniaturization of entropy is the utilization of the energy of thermal devices such as micro heat exchangers, micromixers, micropumps and cooling microelectromechanical devices. Originality/value An attentive review of the literature discloses that quite a few studies have been conducted on entropy generation analysis of a fully developed MHD Poiseuille flow of NFs through a permeable channel subject to the velocity slip and convective heating conditions at the walls.

Coupling of BGK lattice Boltzmann method and experimental rheological/thermal behavior of Al2O3–oil nanolubricant for modeling of a finned thermal storage

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muhammad Aqeel Ashraf ◽  
Zhenling Liu ◽  
Emad Hasani Malekshah ◽  
Lioua Kolsi ◽  
Ahmed Kadhim Hussein
Keyword(s):  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Thermal Storage ◽  
Bejan Number ◽  
Content Type ◽  
Thermal Analyzer ◽  
Complex Boundary ◽  
Numerical Process ◽  
Boltzmann Method

Purpose The purpose of the present work is to investigate the hydrodynamic and thermal performance of a thermal storage based on the numerical and experimental approaches using the lattice Boltzmann method and the experimental observation on the thermo-physical properties of the operating fluid. Design/methodology/approach For this purpose, the Al2O3 nanoparticle is added to the lubricant with four nanoparticle concentrations, including 0.1, 0.2, 0.4 and 0.6Vol.%. After preparing the nanolubricant samples, the thermal conductivity and dynamic viscosity of nanolubricant are measured using thermal analyzer and viscometer, respectively. Finally, the extracted data are used in the numerical simulation using provided correlations. In the numerical process, the lattice Boltzmann equations based on Bhatnagar–Gross Krook model are used. Also, some modifications are applied to treat with the complex boundary conditions. In addition, the second law analysis is used based on the local and total views. Findings Different types of results are reported, including the flow structure, temperature distribution, contours of local entropy generation, value of average Nusselt number, value of entropy generation and value of Bejan number. Originality/value The originality of this work is combining a modern numerical methodology with experimental data to simulate the convective flow for an industrial application.

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