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.

scholarly journals Second law analysis for MHD permeable channel flow with variable electrical conductivity and asymmetric Navier slips

Open Physics ◽  
2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Adetayo S. Eegunjobi ◽  
Oluwole D. Makinde
Keyword(s):  
Electrical Conductivity ◽  
Channel Flow ◽  
Second Law ◽  
Bejan Number ◽  
Temperature Profiles ◽  
Governing Equations ◽  
Permeable Channel ◽  
Entropy Generation Number ◽  
Navier Slip ◽  
Second Law Analysis

AbstractThe inherent irreversibility in a steady hydromagnetic permeable channel flow of a conducting fluid with variable electrical conductivity and asymmetric Navier slip at the channel walls in the presence of induced electric field is theoretically investigated. The model nonlinear governing equations are obtained and numerically solved using shooting quadrature. Numerical results for velocity and temperature profiles are utilised to compute the entropy generation number and the Bejan number. Pertinent results are displayed graphically and discussed quantitatively.

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.

scholarly journals Entropy Generation in Couette Flow Through a Deformable Porous Channel

2019 ◽  
Vol 4 (2) ◽  
pp. 575-590 ◽  
Author(s):  
G. Gopi Krishna ◽  
S. Sreenadh ◽  
A.N.S. Srinivas
Keyword(s):  
Porous Medium ◽  
Temperature Distribution ◽  
Couette Flow ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Porous Channel ◽  
Injection Velocity ◽  
Bejan Number ◽  
Parallel Plates

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.

scholarly journals Second Law Analysis of Mixed Convection in a Laminar, Non-Newtonian Fluid Flow through a Vertical Channel

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Rama Subba Reddy Gorla
Keyword(s):  
Mixed Convection ◽  
Entropy Generation ◽  
Viscosity Index ◽  
Vertical Channel ◽  
Temperature Fields ◽  
Bejan Number ◽  
High Entropy ◽  
Entropy Generation Number ◽  
Second Law Analysis ◽  
Flow Through

The fully developed mixed convection of non-Newtonian laminar flow through a vertical channel is investigated. The boundary conditions of uniform and unequal temperature prescribed at the channel walls are considered. The velocity and temperature fields are obtained by analytically solving the momentum and energy balance equations. The velocity and temperature distributions are used to calculate the entropy generation number (), the irreversibility ratio (Φ), and the Bejan number (Be) for several values of the viscous dissipation parameter (), the viscosity index (), and the appropriate dimensionless coordinates. The results show us the regions of high entropy generation.

Entropy Analysis of MHD Variable Thermal Conductivity Fluid Flow Past a Convectively Heated Stretching Cylinder

2018 ◽  
Vol 387 ◽  
pp. 244-259 ◽  
Author(s):  
Sanatan Das ◽  
Subhajit Chakraborty ◽  
Oluwole Daniel Makinde ◽  
Rabindra Nath Jana
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Entropy Generation ◽  
Numerical Solutions ◽  
Fluid Velocity ◽  
Convective Heating ◽  
Bejan Number ◽  
Stretching Cylinder ◽  
Entropy Analysis ◽  
Entropy Generation Number

The present study is related to entropy analysis during magnetohydrodynamic (MHD) boundary layer flow of a viscous incompressible electrically conducting fluid past a stretching cylinder with convective heating in the presence of a transverse magnetic field. The governing boundary layer equations in cylindrical form are simplified by means of appropriate similarity transformations. Numerical solutions with high precision are obtained using Runge-Kutta fourth order scheme with eminent shooting technique. The effects of the pertinent parameters on the fluid velocity, temperature, entropy generation number, Bejan number as well as the shear stress at the surface of the cylinder are discussed graphically and quantitatively. It is examined that due to the presence of magnetic field, entropy generation can be controlled and reduced. Bejan number is plotted to present a comparative analysis of entropy generation due to heat transfer and fluid friction. It is found that Bejan number is an increasing function of Biot number.

scholarly journals Analytical Assessment of (Al2O3–Ag/H2O) Hybrid Nanofluid Influenced by Induced Magnetic Field for Second Law Analysis with Mixed Convection, Viscous Dissipation and Heat Generation

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wasim Ullah Khan ◽  
Muhammad Awais ◽  
Nabeela Parveen ◽  
Aamir Ali ◽  
Saeed Ehsan Awan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Heat Generation ◽  
Transfer Rate ◽  
Second Law ◽  
Hybrid Nanofluid ◽  
Entropy Generation Number ◽  
Generation Number ◽  
Second Law Analysis

The current study is an attempt to analytically characterize the second law analysis and mixed convective rheology of the (Al2O3–Ag/H2O) hybrid nanofluid flow influenced by magnetic induction effects towards a stretching sheet. Viscous dissipation and internal heat generation effects are encountered in the analysis as well. The mathematical model of partial differential equations is fabricated by employing boundary-layer approximation. The transformed system of nonlinear ordinary differential equations is solved using the homotopy analysis method. The entropy generation number is formulated in terms of fluid friction, heat transfer and Joule heating. The effects of dimensionless parameters on flow variables and entropy generation number are examined using graphs and tables. Further, the convergence of HAM solutions is examined in terms of defined physical quantities up to 20th iterations, and confirmed. It is observed that large λ1 upgrades velocity, entropy generation and heat transfer rate, and drops the temperature. High values of δ enlarge velocity and temperature while reducing heat transport and entropy generation number. Viscous dissipation strongly influences an increase in flow and heat transfer rate caused by a no-slip condition on the sheet.

Thermodynamic optimization of nanofluid flow over a non-isothermal wedge with nonlinear radiation and activation energy

2021 ◽  
Author(s):  
M R Acharya ◽  
P Mishra ◽  
Satyananda Panda
Keyword(s):  
Heat Transfer ◽  
Activation Energy ◽  
Reynolds Number ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Mathematical Formulation ◽  
Bejan Number ◽  
Nanofluid Flow ◽  
Entropy Generation Number ◽  
Generation Number

Abstract This paper analyses the augmentation entropy generation number for a viscous nanofluid flow over a non-isothermal wedge including the effects of non-linear radiation and activation energy. We discuss the influence of thermodynamically important parameters during the study, namely, the Bejan number, entropy generation number, and the augmentation entropy generation number. The mathematical formulation for thermal conductivity and viscosity of nanofluid for Al2O3 − EG mixture has been considered. The results were numerically computed using implicit Keller-Box method and depicted graphically. The important result is the change in augmentation entropy generation number with Reynolds number. We observed that adding nanoparticles (volume fraction) tend to enhance augmentation entropy generation number for Al2O3 − EG nanofluid. Further, the investigation on the thermodynamic performance of non-isothermal nanofluid flow over a wedge reveals that adding nanoparticles to the base fluid is effective only when the contribution of heat transfer irreversibility is more than fluid friction irreversibility. This work also discusses the physical interpretation of heat transfer irreversibility and pressure drop irreversibility. This dependency includes Reynolds number and volume fraction parameter. Other than these, the research looked at a variety of physical characteristics associated with the flow of fluid, heat and mass transfer.

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.

scholarly journals Numerical investigation of entropy generation in laminar forced convection flow over inclined backward and forward facing steps in a duct under bleeding condition

2014 ◽  
Vol 18 (2) ◽  
pp. 479-492 ◽  
Author(s):  
Meysam Atashafrooz ◽  
Nassab Gandjalikhan ◽  
Babak Ansari
Keyword(s):  
Numerical Investigation ◽  
Forced Convection ◽  
Entropy Generation ◽  
Fluid Dynamic ◽  
Numerical Results ◽  
Convection Flow ◽  
Bejan Number ◽  
Entropy Generation Number ◽  
Forced Convection Flow ◽  
Laminar Forced Convection

A numerical investigation of entropy generation in laminar forced convection of gas flow over a recess including two inclined backward and forward facing steps in a horizontal duct under bleeding condition is presented. For calculation of entropy generation from the second law of thermodynamics in a forced convection flow, the velocity and temperature distributions are primary needed. For this purpose, the two-dimensional Cartesian coordinate system is used to solve the governing equations which are conservations of mass, momentum and energy. These equations are solved numerically using the computational fluid dynamic techniques to obtain the temperature and velocity fields, while the blocked region method is employed to simulate the inclined surface. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. The numerical results are presented graphically and the effects of bleeding coefficient and recess length as the main parameters on the distributions of entropy generation number and Bejan number are investigated. Also, the effect of Reynolds number and bleeding coefficient on total entropy generation which shows the amount of flow irreversibilities is presented for two recess length. The use of present results in the design process of such thermal system would help the system attain the high performance during exploitation. Comparison of numerical results with the available data published in open literature shows a good consistency.

scholarly journals Effects of non-uniform nanoparticle concentration on entropy generation

2021 ◽  
Vol 68 (1 Jan-Feb) ◽  
Author(s):  
Ahmer Mehmood ◽  
Sajid Khan ◽  
Muhammad Usman
Keyword(s):  
Entropy Production ◽  
Entropy Generation ◽  
Working Fluid ◽  
Physical Parameters ◽  
Bejan Number ◽  
Total Entropy ◽  
Entropy Generation Number ◽  
Self Similar Solution ◽  
Nanoparticles Concentration ◽  
The Impact

The entropy generation analysis of a thermal process is capable of determining the efficiency of that process and is therefore helpful to optimize the thermal system operating under various conditions. There are several ingredients upon which the phenomenon of entropy generation can depend, such as the nature of flow and the fluid, the assumed conditions, and the material properties of the working fluid. However, the dependence of entropy generation phenomenon upon such properties has so far not been fully realized, in view of the existing literature. On the other hand, based upon the existing studies, it has been established that the non-uniform concentration of nanoparticles in the base fluid does cause to enhance the heat transfer rate. Therefore, it is logical to investigate the entropy production under the impact of non-homogenous distribution of nanoparticles. Based upon this fact the aim of current study is to explore a comprehensive detail about the influence of non-homogeneous nanoparticles concentration on entropy production phenomenon by considering a laminar viscous flow past a moving continuous flat plate. Non-uniform concentration is considered in the nanofluid modeling in which the Brownian and thermophoretic diffusions are considered which impart significant effects on velocity and temperature profiles. An exact self-similar solution to this problem is observed to be possible and is reported. The effects of various controlling physical parameters such as Brinkman number, Schmidt number, Prandtl number, diffusion parameter, and concentration parameter on both local as well as total entropy generation number and Bejan number are elaborated by several graphs and Tables. The obtained results reveal a significant impact of all aforementioned parameters on entropy generation characteristics. It is observed that by a 20% increase in nanoparticles concentration the total entropy generation is increased up to 67% for a set of fixed values of remaining parameters.

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