Entropy Analysis in MHD Flow with Heat Source and Thermal Radiation Past a Stretching Sheet in a Porous Medium

2018 ◽  
Vol 387 ◽  
pp. 364-372 ◽  
Author(s):  
Oluwole Daniel Makinde ◽  
Adetayo Samuel Eegunjobi

In this paper, we conducted the thermodynamics first and second laws analyses on hydromagnetic boundary layer flow of an incompressible electrically conducting viscous fluid past a vertically stretching sheet embedded in a porous medium with heat source and thermal radiation. The governing equations describing the problem are converted to a system of nonlinear ordinary differential equations using appropriate similarity variables. Using shooting technique coupled with Runge-Kutta-Ferhlberg integration scheme, the model boundary value problem is numerically tackled. The parametric effects on fluid velocity, temperature, skin friction, Nusselt number, entropy generation rate and the Bejan number are presented graphically and discussed quantitatively. Our results revealed among others, that the entropy generation is enhanced by magnetic field, thermal radiation and heat source but lessened by increasing porous medium permeability and buoyancy force.

2021 ◽  
Vol 53 (3) ◽  
pp. 395-414
Author(s):  
Oluwole Daniel Makinde ◽  
Adetayo Samuel Eegunjobi

This work investigated the thermal putrefaction and inherent irreversibility in a steady flow of an incompressible inconstant viscosity radiating fluid within two concentric pipes filled with a porous medium. Following the Brinkmann-Darcy-Forchheimer approach, the nonlinear differential equations governing the model were obtained. The model boundary value problem was addressed numerically via a shooting quadrature with the Runge-Kutta-Fehlberg integration scheme. The effects of diverse emerging parameters on the fluid velocity, temperature, skin friction, Nusselt number, entropy generation rate and the Bejan number are provided in graphs and discussed in this paper.


2018 ◽  
Vol 8 (12) ◽  
pp. 2588 ◽  
Author(s):  
Sayer Alharbi ◽  
Abdullah Dawar ◽  
Zahir Shah ◽  
Waris Khan ◽  
Muhammad Idrees ◽  
...  

In this article, we have briefly examined the entropy generation in magnetohydrodynamic (MHD) Eyring–Powell fluid over an unsteady oscillating porous stretching sheet. The impact of thermal radiation and heat source/sink are taken in this investigation. The impact of embedded parameters on velocity function, temperature function, entropy generation rate, and Bejan number are deliberated through graphs, and discussed as well. By studying the entropy generation in magnetohydrodynamic Eyring–Powell fluid over an unsteady oscillating porous stretching sheet, the entropy generation rate is reduced with escalation in porosity, thermal radiation, and magnetic parameters, while increased with the escalation in Reynolds number. Also, the Bejan number is increased with the escalation in porosity and magnetic parameter, while increased with the escalation in thermal radiation parameter. The impact of skin fraction coefficient and local Nusselt number are discussed through tables. The partial differential equations are converted to ordinary differential equation with the help of similarity variables. The homotopy analysis method (HAM) is used for the solution of the problem. The results of this investigation agree, satisfactorily, with past studies.


2017 ◽  
Vol 374 ◽  
pp. 47-66 ◽  
Author(s):  
Adetayo Samuel Eegunjobi ◽  
Oluwole Daniel Makinde

In this paper, both first and second laws of thermodynamics are employed to investigate the combined effects of magnetic field, buoyancy force, velocity slip, suction/injection, porous medium permeability, thermal radiation absorption, viscous and Joule heating on mixed convective flow of an electrical conducting Casson fluid in a vertical channel. The dimensionless governing equations are obtained and solved numerically using a shooting technique coupled with a fourth order Runge-Kutta-Fehlberg integration scheme. The influence of various thermophysical parameters on velocity and temperature profiles, skin friction, Nusselt number, entropy generation rate and Bejan number are presented graphically and discussed quantitatively. It is found that with appropriate combination of thermophysical parameter values the entropy generation rate in the presence of an applied magnetic field can successfully.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fazle Mabood ◽  
Anum Shafiq ◽  
Waqar Ahmed Khan ◽  
Irfan Anjum Badruddin

Purpose This study aims to investigate the irreversibility associated with the Fe3O4–Co/kerosene hybrid-nanofluid past a wedge with nonlinear radiation and heat source. Design/methodology/approach This study reports the numerical analysis of the hybrid nanofluid model under the implications of the heat source and magnetic field over a static and moving wedge with slips. The second law of thermodynamics is applied with nonlinear thermal radiation. The system that comprises differential equations of partial derivatives is remodeled into the system of differential equations via similarity transformations and then solved through the Runge–Kutta–Fehlberg with shooting technique. The physical parameters, which emerges from the derived system, are discussed in graphical formats. Excellent proficiency in the numerical process is analyzed by comparing the results with available literature in limiting scenarios. Findings The significant outcomes of the current investigation are that the velocity field uplifts for higher velocity slip and magnetic strength. Further, the heat transfer rate is reduced with the incremental values of the Eckert number, while it uplifts with thermal slip and radiation parameters. An increase in Brinkmann’s number uplifts the entropy generation rate, while that peters out the Bejan number. The results of this study are of importance involving in the assessment of the effect of some important design parameters on heat transfer and, consequently, on the optimization of industrial processes. Originality/value This study is original work that reports the hybrid nanofluid model of Fe3O4–Co/kerosene.


2019 ◽  
Vol 4 (2) ◽  
pp. 575-590 ◽  
Author(s):  
G. Gopi Krishna ◽  
S. Sreenadh ◽  
A.N.S. Srinivas

AbstractThe present study examines the entropy generation on Couette flow of a viscous fluid in parallel plates filled with deformable porous medium. The fluid is injected into the porous channel perpendicular to the lower wall with a constant velocity and is sucked out of the upper wall with same velocity .The coupled phenomenon of the fluid flow and solid deformation in the porous medium is taken in to consideration. The exact expressions for the velocity of fluid, solid displacement and temperature distribution are found analytically. The effect of pertinent parameters on the fluid velocity, solid displacement and temperature profiles are discussed in detail. In the deformable porous layer, it is noticed that the velocity of fluid, solid displacement and temperature distribution are decreases with increasing the suction/injection velocity parameter. The results obtained for the present flow characteristic reveal several interesting behaviors that warrant further study on the deformable porous media. Furthermore, the significance of drag and the volume fraction on entropy generation number and Bejan number are discussed with the help of graphs.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
K. S. Balamurugan ◽  
N. Udaya Bhaskara Varma ◽  
J. L. Ramaprasad

AbstractThe current investigation is concerned with heat transfer and entropy generation analysis in a horizontal channel brimming with porous medium in the existence of aligned magnetic field, viscous and joules dissipation and temperature gradient heat source. The boundary conditions are treated as constant values for velocity and temperature at lower and upper walls. An explicit solution of governing equations has been attained in closed system. The repercussions of pertinent parameters on the fluid velocity, temperature, entropy generation and Bejan number are conferred and scrutinized through graphs in detail. Additionally the expressions for shear stress and the rate of heat transfer coefficients at the channel walls are derived and results obtained are physically interpreted through tables. From the conquered results, it is addressed that Brinkman number Br enhances boundary layer thickness. Entropy generation increases with intensifying values of $$M$$ M , aligned angle ϕ, temperature gradient heat source parameter Q, characteristic temperature ration $$\omega$$ ω and permeability parameter K. The shear stress is same at both the lower and upper walls.


2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Kun Yang ◽  
Hao Chen ◽  
Jiabing Wang

Convective heat transfer in a channel partially filled with porous medium has received a lot of attention due to its wide engineering applications. However, most researches focused on a channel partially filled with single layer porous medium. In this paper, we will analyze the heat transfer and entropy generation inside a channel partially filled with N-layer porous media. The flow and the heat transfer in the porous region are described by the Darcy–Brinkman model and the local thermal nonequilibrium model, respectively. At the porous-free fluid interface, the momentum and the heat transfer are described by the stress jump boundary condition and the heat flux jump boundary condition, respectively; while at the interface between two different porous layers, the momentum and the heat transfer are described by the stress continuity boundary condition and the heat flux continuity boundary condition, respectively. The analytical solutions for the velocity and temperature in the channel are derived and used to calculate the overall Nusselt number, the total entropy generation rate, the Bejan number, and the friction factor. Furthermore, the performances of the flow and heat transfer of a channel partially filled with third-layer porous media are studied.


Author(s):  
M. Ijaz Khan ◽  
Salman Ahmad ◽  
T. Hayat ◽  
A. Alsaedi

Abstract The main theme of this paper is to investigate entropy generation analysis for unsteady three-dimensional flow of viscous (Newtonian) fluid between two horizontal parallel plates. Lower plate is porous and stretching while upper plate squeezed downward. Further effects of nonlinear thermal radiation, viscous dissipation, heat source/sink and activation energy are accounted. Entropy generation rate calculated in terms of thermal radiation, fluid diffusion and fluid friction. Transformations procedure used lead to reduction of PDE’s into ordinary ones. Built-in-Shooting technique is used for the computational analysis. Impacts of different flow variables on temperature, velocity, concentration, volumetric entropy generation and Bejan number are discussed and presented through graphs. Temperature and concentration gradient are discussed numerically. It is examined from obtained results that velocity of liquid particle decays through larger estimation of squeezing parameter. It is also examined that temperature distribution enhances for higher estimation of radiative heat flux. Moreover temperature and concentration gradient increase for larger squeezing parameter.


2018 ◽  
Vol 10 (11) ◽  
pp. 168781401878952 ◽  
Author(s):  
Taza Gul ◽  
Irfan Haleem ◽  
Ibrar Ullah ◽  
Muhammad Altaf Khan ◽  
Ebenezer Bonyah ◽  
...  

This research inspects the liquid film flow of the nanofluid in a permeable medium with the consequence of thermal radiation over a stretching sheet. The viscidness and thermal conduction of the nanofluid varies with temperature in such a manner that the thermal conductivity considered in direct relation while the viscosity considered inversely proportional to the temperature field. The invariable magnetic field applies vertically to the flow field in the existence of entropy generation. For the above-mentioned nanofluid study, Buongiorno’s model is used. The leading equations are changed into a set of third- and second-order nonlinear coupled differential equations. These nonlinear ordinary differential equations are solved using the optimal approach of homotopy analysis method. The physical appearance of the modelled parameters based on the liquid film thickness is mainly focused. Furthermore, the influence of embedded parameters like variable viscosity parameter [Formula: see text] Prandtl number [Formula: see text] Schmidt number [Formula: see text] Brinkman number [Formula: see text] Brownian motion constraint [Formula: see text] thermophoresis constraint [Formula: see text] magnetic parameter [Formula: see text] thermal radiation parameter [Formula: see text] Reynolds number [Formula: see text] diffusion coefficient [Formula: see text] non-dimension temperature variation [Formula: see text] and non-dimension concentration variation [Formula: see text] is observed on the velocity pitch, temperature gradient and concentration sketch. The consequence of parameters due to entropy generation and Bejan number has also been observed in this work. The important physically quantities of skin friction coefficient, the local Nusselt number and Sherwood number have also been studied. Residual error and optimal values have been calculated for the range of each physical parameter. The present work is compared with the published work and the comparison has been shown physically and numerically.


Sign in / Sign up

Export Citation Format

Share Document