scholarly journals Second Law Analysis of Dissipative Flow over a Riga Plate with Non-Linear Rosseland Thermal Radiation and Variable Transport Properties

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 615 ◽  
Author(s):  
Muhammad Afridi ◽  
Muhammad Qasim ◽  
Abid Hussanan
Keyword(s):  
Thermal Conductivity ◽  
Entropy Generation ◽  
Numerical Solutions ◽  
Variable Viscosity ◽  
Frictional Heating ◽  
Variable Thermal Conductivity ◽  
Heat Transfer Analysis ◽  
Entropy Generation Number ◽  
Non Linear ◽  
Riga Plate

In this article, we investigated entropy generation and heat transfer analysis in a viscous flow induced by a horizontally moving Riga plate in the presence of strong suction. The viscosity and thermal conductivity of the fluid are taken to be temperature dependent. The frictional heating function and non-linear radiation terms are also incorporated in the entropy generation and energy equation. The partial differential equations which model the flow are converted into dimensionless form by using proper transformations. Further, the dimensionless equations are reduced by imposing the conditions of strong suction. Numerical solutions are obtained using MATLAB boundary value solver bvp4c and used to evaluate the entropy generation number. The influences of physical flow parameters arise in the mathematical modeling are demonstrated through various graphs. The analysis reveals that velocity decays whereas entropy generation increases with rising values of variable viscosity parameter. Furthermore, entropy generation decays with increasing variable thermal conductivity parameter.

Effects of Energy Dissipation and Variable Thermal Conductivity on Entropy Generation Rate in Mixed Convection Flow

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Muhammad Qasim ◽  
Muhammad Idrees Afridi
Keyword(s):  
Thermal Conductivity ◽  
Energy Dissipation ◽  
Mixed Convection ◽  
Entropy Generation ◽  
Variable Thermal Conductivity ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Entropy Generation Number ◽  
Similarity Transformations ◽  
Generation Number

Analysis of entropy generation in mixed convection flow over a vertically stretching sheet has been carried out in the presence of variable thermal conductivity and energy dissipation. Governing equations are reduced to self-similar ordinary differential equations via similarity transformations and are solved numerically by applying shooting and fourth-order Runge–Kutta techniques. The expressions for entropy generation number and Bejan number are also obtained by using similarity transformations. The influence of embedding physical parameters on quantities of interest is discussed through graphical illustrations. The results reveal that entropy generation number increases significantly in the vicinity of stretching surface and gradually dies out as one move away from the sheet. Also, the entropy generation number decreases with an increase in temperature difference parameter. Moreover, entropy generation number enhances with an enhancement in the Eckert number, Prandtl number, and variable thermal conductivity parameter.

Semi-analytical Evaluation of Entropy Generation in 1-D Heat Conduction with Variable Thermal Conductivity

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
T. Anupkumar ◽  
A. Praveen Reddy ◽  
Noble Sharma ◽  
N. Narayan Rao ◽  
B. Srinivasa Rao
Keyword(s):  
Thermal Conductivity ◽  
Entropy Generation ◽  
Governing Equation ◽  
Internal Heat ◽  
Variable Thermal Conductivity ◽  
Heat Diffusion ◽  
Entropy Generation Number ◽  
Entropy Transport ◽  
Steady State Heat ◽  
Steady State Heat Transfer

In the present study, steady state heat transfer in a slab is analysed by applying the principle of variation calculus to the entropy generation minimization. The governing equation of the phenomena is obtained by minimizing the total entropy generation over the slab by considering the irreversibility and variation of thermal conductivity as a function of spatial co-ordinates. The governing equation is solved to obtain the temperature distribution, internal heat generation due to irreversibility, entropy generation number and entropy transport into system. The apparent heat sources that come into existence because of the irreversibility in heat diffusion have made the minimization of entropy generation feasible.

APPLICATION OF THE NEW SPECTRAL HOMOTOPY ANALYSIS METHOD (SHAM) IN THE NON-LINEAR HEAT CONDUCTION AND CONVECTIVE FIN PROBLEM WITH VARIABLE THERMAL CONDUCTIVITY

2012 ◽  
Vol 09 (03) ◽  
pp. 1250039 ◽  
Author(s):  
S. S. MOTSA
Keyword(s):  
Thermal Conductivity ◽  
Homotopy Analysis Method ◽  
Numerical Solutions ◽  
Variable Thermal Conductivity ◽  
Analysis Method ◽  
Linear Heat ◽  
Non Linear ◽  
Homotopy Analysis ◽  
Convective Fin ◽  
Spectral Homotopy Analysis Method

In this work, we demonstrate the efficiency of the newly developed spectral homotopy analysis method (SHAM) in solving non-linear heat transfer equations. We demonstrate the applicability of the method by solving the problem of steady conduction in a slab and the convective fin equation with variable thermal conductivity. New closed form explicit analytic solutions of the governing non-linear equations are obtained and compared with the SHAM results and numerical solutions. The results reveal that the new SHAM approach is very accurate and efficient and converges much faster than the standard homotopy analysis method.

scholarly journals The Kirchhoff Transformation for Convective-radiative Thermal Problemsin Fins

2021 ◽  
Vol 15 ◽  
pp. 12-21
Author(s):  
Jonatas Motta Quirino ◽  
Eduardo Dias Correa ◽  
Rodolfo do Lago Sobral
Keyword(s):  
Thermal Conductivity ◽  
Boundary Conditions ◽  
Thermal Radiation ◽  
Heat Dissipation ◽  
Variable Thermal Conductivity ◽  
Dirichlet Boundary Conditions ◽  
Heat Transfer Analysis ◽  
Temperature Function ◽  
Kirchhoff Transformation ◽  
Comparison Of The Results

- The present work describes the thermal profile of a single dissipation fin, where their surfaces reject heat to the environment. The problem happens in steady state, which is, all the analysis occurs after the thermal distribution reach heat balance considering that the fin dissipates heat by conduction, convection and thermal radiation. Neumann and Dirichlet boundary conditions are established, characterizing that heat dissipation occurs only on the fin faces, in addition to predicting that the ambient temperature is homogeneous. Heat transfer analysis is performed by computational simulations using appropriate numerical methods. The most of solutions in the literature consider some simplifications as constant thermal conductivity and linear boundary conditions, this work addresses this subject. The method applied is the Kirchhoff Transformation, that uses the thermal conductivity variation to define the temperatures values, once the thermal conductivity variate as a temperature function. For the real situation approximation, this work appropriated the silicon as the fin material to consider the temperature function at each point, which makes the equation that governs the non-linear problem. Finally, the comparison of the results obtained with typical results proves that the assumptions of variable thermal conductivity and heat dissipation by thermal radiation are crucial to obtain results that are closer to reality.

Thermal transport of hybrid nanofluids with entropy generation: A numerical simulation

2021 ◽  
pp. 2150218
Author(s):  
Hassan Waqas ◽  
Faisal Fareed Bukhari ◽  
Taseer Muhammad ◽  
Umar Farooq
Keyword(s):  
Thermal Conductivity ◽  
Thermal Radiation ◽  
Entropy Generation ◽  
Industrial Process ◽  
Velocity Slip ◽  
Variable Thermal Conductivity ◽  
Process Improvements ◽  
Radiation Entropy ◽  
Hybrid Nanofluids ◽  
Nonlinear Pattern

In this research, thermal radiation, entropy generation and variable thermal conductivity effects on hybrid nanofluids by moving sheet are analyzed. The liquid is placed by stretchable flat wall that is flowing in a nonlinear pattern. Thermal conductivity changes with temperature governed by thermal radiation and MHD is incorporated. Approximations of boundary layer correspond to a set of PDEs which are then changed into ODEs by considering suitable variables. The resulting ODEs are solved using the bvp4c method. The implication with considerable physical characteristics on temperature, entropy generation and velocity profile is graphically represented and numerically discussed. Entropy generation increases for increasing Reynolds number, velocity slip parameter, Brinkman number and magnetic parameter. Scientists have recently established a rising interest in the importance of nanoparticles due to their numerous technical, industrial and commercial uses. The provided insights can be used in extrusion application areas, macromolecules, biomimetic systems, energy production and industrial process improvements.

Non-similar solution of Casson nanofluid with variable viscosity and variable thermal conductivity

2019 ◽  
Vol 30 (8) ◽  
pp. 3919-3938 ◽  
Author(s):  
Ankita Bisht ◽  
Rajesh Sharma
Keyword(s):  
Thermal Conductivity ◽  
Stretching Sheet ◽  
Variable Viscosity ◽  
Variable Thermal Conductivity ◽  
Solar Thermal ◽  
Content Type ◽  
Casson Nanofluid ◽  
Solar Thermal Collectors ◽  
Variation Parameter ◽  
Nonlinear Stretching

Purpose The purpose of this study is to provide a numerical investigation of Casson nanofluid along a vertical nonlinear stretching sheet with variable thermal conductivity and viscosity. Design/methodology/approach The boundary-layer equations are presented in the dimensionless form using proper non-similar transformations. The subsequent non-dimensional nonlinear partial differential equations are solved using the implicit finite difference technique. To linearize the nonlinear terms present in these equations, the quasilinearization technique is used. Findings The investigation showed graphically the temperature, velocity and nanoparticle volume fraction for particular included physical parameters. It is observed that the velocity profile decreases with an increase in the values of Casson fluid parameter while increases with an increase in the viscosity variation parameter. The temperature profile enhances for large values of velocity variation parameter and thermal conductivity parameter while it reduces for large values of thermal buoyancy parameter. Further, the Nusselt number and skin-friction coefficient are introduced which are helpful in determining the physical aspects of Casson nanofluid flow. Practical implications The immediate control of heat transfer in the industrial system is crucial because of increasing energy prices. Recently, nanotechnology is proposed to control the heat transfer phenomenon. Ongoing research in complex nanofluid has been fruitful in various applications such as solar thermal collectors, nuclear reactors, electronic equipment and diesel–electric conductor. A reasonable amount of nanoparticle when added to the base fluid in solar thermal collectors serves to deeper absorption of incident radiation, and hence it upgrades the efficiency of the solar thermal collectors. Originality/value The non-similar solution of Casson nanofluid due to a vertical nonlinear stretching sheet with variable viscosity and thermal conductivity is discussed in this work.

MHD slip flow and convective heat transfer due to a moving plate with effects of variable viscosity and thermal conductivity

2020 ◽  
Vol 16 (5) ◽  
pp. 991-1018
Author(s):  
Mahantesh M. Nandeppanavar ◽  
M.C. Kemparaju ◽  
R. Madhusudhan ◽  
S. Vaishali
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Differential Equations ◽  
Radiation Effects ◽  
Variable Viscosity ◽  
Heat Transfer Analysis ◽  
Concentration Profiles ◽  
Moving Plate ◽  
Content Type

PurposeThe steady two-dimensional laminar boundary layer flow, heat and mass transfer over a flat plate with convective surface heat flux was considered. The governing nonlinear partial differential equations were transformed into a system of nonlinear ordinary differential equations and then solved numerically by Runge–Kutta method with the most efficient shooting technique. Then, the effect of variable viscosity and variable thermal conductivity on the fluid flow with thermal radiation effects and viscous dissipation was studied. Velocity, temperature and concentration profiles respectively were plotted for various values of pertinent parameters. It was found that the momentum slip acts as a boost for enhancement of the velocity profile in the boundary layer region, whereas temperature and concentration profiles decelerate with the momentum slip.Design/methodology/approachNumerical Solution is applied to find the solution of the boundary value problem.FindingsVelocity, heat transfer analysis is done with comparing earlier results for some standard cases.Originality/value100

Effect of thermal asymmetries on the entropy generation analysis of a variable viscosity Couette–Poiseuille flow

2017 ◽  
Vol 231 (5) ◽  
pp. 1011-1024 ◽  
Author(s):  
Pranab K Mondal ◽  
Harshad Gaikwad ◽  
Pranab Kumar Kundu ◽  
Somchai Wongwises
Keyword(s):  
Nusselt Number ◽  
Pressure Gradient ◽  
Entropy Generation ◽  
Variable Viscosity ◽  
Applied Pressure ◽  
Analytical Framework ◽  
Simultaneous Action ◽  
Entropy Generation Rate ◽  
Parallel Plates ◽  
Entropy Generation Number

The influence of viscous dissipation on forced convective heat transfer and entropy generation rate in the conduction limit for a variable-viscosity flow between asymmetrically heated parallel plates is studied in an analytical framework consistent with perturbation method. The study considers a flow of Newtonian fluid under the simultaneous action of an applied pressure gradient and an axial movement of the upper plate. The present study emphasizes on the effect of dissipative heat produced by the movable upper plate as well as viscous heating generated due to applied pressure gradient on the underlying thermo-hydrodynamic transport. A few non-dimensional parameters such as dimensionless upper plate velocity, degree of asymmetry parameter and Brinkman number have been defined and their influential role on the variation of temperature profile, the Nusselt number and entropy generation number has been discussed in detail. The study shows that the variation of Nusselt number exhibits an unbounded swing, which, in turn, leads to appearance of the point of singularities at some cases of asymmetrical plate heating. Finally, the source of appearance of point of singularities has been discussed in view of the energy balance, and from the second-law analysis of thermodynamics.

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