scholarly journals Entropy generation optimization and activation energy in nonlinear mixed convection flow of a tangent hyperbolic nanofluid

2018 ◽  
Vol 133 (8) ◽  
Author(s):  
M. Ijaz Khan ◽  
Tufail A. Khan ◽  
Sumaira Qayyum ◽  
T. Hayat ◽  
Muhammad Imran Khan ◽  
...  
Keyword(s):  
Activation Energy ◽  
Mixed Convection ◽  
Entropy Generation ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Nonlinear Mixed Convection

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.

scholarly journals MHD Nonlinear Mixed Convection Flow of Micropolar Nanofluid over Nonisothermal Sphere

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Wubshet Ibrahim ◽  
Chaluma Zemedu
Keyword(s):  
Boundary Layer ◽  
Mixed Convection ◽  
Mathematical Formulation ◽  
Magnetic Field Effect ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Nonlinear Boundary Value Problems ◽  
Micropolar Nanofluid ◽  
Nonlinear Mixed Convection

In this paper, two-dimensional steady laminar boundary layer flow of a nonlinear mixed convection flow of micropolar nanofluid with Soret and magnetic field effect over a nonisothermal sphere is evaluated. The mathematical formulation for the flow problem has been made with appropriate similarity transformation and dimensionless variables, and the main nonlinear boundary value problems were reduced into mixed high-order nonlinear ordinary differential equations. Solution for velocity, microrotation, temperature, and concentration has been obtained numerically. The equations were calculated using method bvp4c from Matlab software for various quantities of main parameters. The effects of various parameters on skin friction coefficient f″0, wall duo stress coefficient -G′0, and convection mass transfer coefficient -Φ′0 are analysed and presented through the graphs and tables. The convergence test has been maintained. For the number of points greater than the suitable mesh number of points, the precision is not influenced but the set time is increased. Moreover, a comparison with a previous paper, obtainable in the literature, has been presented and an excellent agreement is obtained. The findings indicate that an increase in the values of nonisothermal parameters (m, P), magnetic Ma, thermal and solutal nonlinear convection (λ, s) parameter, and Soret number is to enhance the temperature difference between the boundary layer and ambient fluid to diffuse which increases the velocity profile f′ζ and their boundary layer thicknesses near the surface of the sphere.

scholarly journals Entropy Generation in Magnetohydrodynamic Mixed Convection Flow over an Inclined Stretching Sheet

Entropy ◽  
2016 ◽  
Vol 19 (1) ◽  
pp. 10 ◽  
Author(s):  
Muhammad Afridi ◽  
Muhammad Qasim ◽  
Ilyas Khan ◽  
Sharidan Shafie ◽  
Ali Alshomrani
Keyword(s):  
Mixed Convection ◽  
Entropy Generation ◽  
Stretching Sheet ◽  
Convection Flow ◽  
Mixed Convection Flow

Entropy generation in radiative motion of tangent hyperbolic nanofluid in presence of activation energy and nonlinear mixed convection

2018 ◽  
Vol 382 (31) ◽  
pp. 2017-2026 ◽  
Author(s):  
M. Ijaz Khan ◽  
Sumaira Qayyum ◽  
T. Hayat ◽  
M. Imran Khan ◽  
A. Alsaedi ◽  
...  
Keyword(s):  
Activation Energy ◽  
Mixed Convection ◽  
Entropy Generation ◽  
Nonlinear Mixed Convection

Minimization of Entropy Generation in MHD Mixed Convection Flow with Energy Dissipation and Joule Heating: Utilization of Sparrow-Quack-Boerner Local Non-Similarity Method

2018 ◽  
Vol 387 ◽  
pp. 63-77 ◽  
Author(s):  
M. Idrees Afridi ◽  
Muhammad Qasim ◽  
Najeeb Alam Khan ◽  
Oluwole Daniel Makinde
Keyword(s):  
Energy Dissipation ◽  
Mixed Convection ◽  
Entropy Generation ◽  
Joule Heating ◽  
Convection Flow ◽  
Physical Parameters ◽  
Mixed Convection Flow ◽  
Entropy Analysis ◽  
Entropy Generation Number ◽  
Similarity Method

This article aims to present the non-similar solution of MHD mixed convection flow using the Sparrow-Quack-Boerner local non-similarity method. Entropy analysis is also performed in the presence of energy dissipation and Joule heating. The buoyancy parameter is chosen as the non-similarity variable and the equations are derived up to the second level of truncation. The dependency of dimensionless velocity profile, temperature distribution, Bejan and entropy generation number on physical parameters has been discussed. As far as the knowledge of the authors is concerned, no attempt has been made on the entropy analysis of MHD mixed convection flow by the local non-similarity method.

Entropy Generation Analysis of Mixed Convection Flow in a Nanofluid Filled Porous Cavity Using a Two-Component Lattice Boltzmann Method

2019 ◽  
Author(s):  
Dhrubajyoti Kashyap ◽  
Anoop K. Dass
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Mixed Convection ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Lattice Boltzmann Model ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Two Phase ◽  
Good Concordance

Abstract In the present work, a comprehensive analysis is made to understand the effect of velocity boundary conditions on the flow and thermal behaviour during mixed convection flow in a nanofluid-saturated porous square cavity. Two different velocity boundary conditions based on the movement of horizontal walls of the cavity are considered. The vertical fixed walls are differentially heated and the horizontal lids are thermally insulated. We have adopted the two-phase thermal lattice Boltzmann model (TLBM) for nanofluid system and modified this model to simulate nanofluid-filled porous medium by incorporating the Brinkman–Forchheimer-extended Darcy model. The current results provide good concordance with the published results computed through conventional numerical techniques. The detailed study of the heat transfer rate, entropy generation is made for discretely varying Richardson numbers (Ri) from 0.1 to 10 and Darcy numbers (Da) from 10−4 to 10−2 while maintaining Grashof number (Gr) at 104 and volume fractions of Cu nanoparticle (ϕ) less than equal to 5%. It is observed from the results that the optimal flow condition in terms of energy efficiency depends on the values of Ri and Da. From the viewpoint of both 1st and 2nd laws of thermodynamics, the performance of nanofluid is not satisfactory compared to the base fluid for current configurations as the augmentation of entropy generation with ϕ is more prominent compared to heat transfer enhancement.

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