scholarly journals Irreversibility Analysis of Hybrid Nanofluid Flow over a Thin Needle with Effects of Energy Dissipation

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 663 ◽  
Author(s):  
Muhammad Idrees Afridi ◽  
I. Tlili ◽  
Marjan Goodarzi ◽  
M. Osman ◽  
Najeeb Alam Khan
Keyword(s):  
Entropy Generation ◽  
Numerical Solutions ◽  
Free Stream ◽  
Thermal Dissipation ◽  
Heat Transfer Analysis ◽  
Stream Velocity ◽  
Physical Parameters ◽  
Hybrid Nanofluid ◽  
Nanofluid Flow ◽  
Flow And Heat Transfer

The flow and heat transfer analysis in the conventional nanofluid A l 2 O 3 − H 2 O and hybrid nanofluid C u − A l 2 O 3 − H 2 O was carried out in the present study. The present work also focused on the comparative analysis of entropy generation in conventional and hybrid nanofluid flow. The flows of both types of nanofluid were assumed to be over a thin needle in the presence of thermal dissipation. The temperature at the surface of the thin needle and the fluid in the free stream region were supposed to be constant. Modified Maxwell Garnet (MMG) and the Brinkman model were utilized for effective thermal conductivity and dynamic viscosity. The numerical solutions of the self-similar equations were obtained by using the Runge-Kutta Fehlberg scheme (RKFS). The Matlab in-built solver bvp4c was also used to solve the nonlinear dimensionless system of differential equations. The present numerical results were compared to the existing limiting outcomes in the literature and were found to be in excellent agreement. The analysis demonstrated that the rate of entropy generation reduced with the decreasing velocity of the thin needle as compared to the free stream velocity. The hybrid nanofluid flow with less velocity was compared to the regular nanofluid under the same circumstances. Furthermore, the enhancement in the temperature profile of the hybrid nanofluid was high as compared to the regular nanofluid. The influences of relevant physical parameters on flow, temperature distribution, and entropy generation are depicted graphically and discussed herein.

Entropy generation of nanofluid flow and heat transfer driven through a paralleled microchannel

2019 ◽  
Vol 97 (6) ◽  
pp. 678-691 ◽  
Author(s):  
Hang Xu ◽  
Ammarah Raees ◽  
Xiao-Hang Xu
Keyword(s):  
Magnetic Field ◽  
Brownian Motion ◽  
Entropy Generation ◽  
Current Model ◽  
Entropy Generation Rate ◽  
Physical Parameters ◽  
Nanofluid Flow ◽  
Buongiorno’S Model ◽  
Flow Models ◽  
Flow And Heat Transfer

In this paper, a fully-developed, immiscible nanofluid flow in a paralleled microchannel in the presence of a magnetic field is investigated. Buongiorno’s model is applied to describe the behaviors of the nanofluid flow. Different from most previous studies on microchannel flow, here the pressure term is considered as unknown, which makes the current model compatible with the commonly accepted channel flow models. The influences of various physical parameters on important physical quantities are given. The entropy generation analysis is performed. Variations of local and global entropy generations with the magnetic field parameter, the electric field, and the viscous dissipation parameter under various ratios of the thermophoresis parameter to the Brownian motion parameter are illustrated. The results indicate that the entropy generation rate strongly depends on the thermophoresis and the Brownian motion parameters. Their increase enhances the total irreversibility of entropy generation.

scholarly journals Shape Effect of Nanosize Particles on Magnetohydrodynamic Nanofluid Flow and Heat Transfer over a Stretching Sheet with Entropy Generation

Entropy ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1171
Author(s):  
Umair Rashid ◽  
Dumitru Baleanu ◽  
Azhar Iqbal ◽  
Muhammd Abbas
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Stretching Sheet ◽  
Graphical Form ◽  
Physical Parameters ◽  
Shape Effect ◽  
Analysis Method ◽  
Nanofluid Flow ◽  
Flow And Heat Transfer ◽  
Homotopy Analysis

Magnetohydrodynamic nanofluid technologies are emerging in several areas including pharmacology, medicine and lubrication (smart tribology). The present study discusses the heat transfer and entropy generation of magnetohydrodynamic (MHD) Ag-water nanofluid flow over a stretching sheet with the effect of nanoparticles shape. Three different geometries of nanoparticles—sphere, blade and lamina—are considered. The problem is modeled in the form of momentum, energy and entropy equations. The homotopy analysis method (HAM) is used to find the analytical solution of momentum, energy and entropy equations. The variations of velocity profile, temperature profile, Nusselt number and entropy generation with the influences of physical parameters are discussed in graphical form. The results show that the performance of lamina-shaped nanoparticles is better in temperature distribution, heat transfer and enhancement of the entropy generation.

scholarly journals Entropy Generation in Cu-Al2O3-H2O Hybrid Nanofluid Flow over a Curved Surface with Thermal Dissipation

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 941 ◽  
Author(s):  
Muhammad Idrees Afridi ◽  
Tawfeeq Abdullah Alkanhal ◽  
Muhammad Qasim ◽  
Iskander Tlili
Keyword(s):  
Differential Equations ◽  
Entropy Generation ◽  
Numerical Results ◽  
Curvilinear Coordinates ◽  
Curved Surface ◽  
Thermal Dissipation ◽  
Solid Boundary ◽  
Radius Of Curvature ◽  
Physical Parameters ◽  
Hybrid Nanofluid

Heat transfer and entropy generation in a hybrid nanoliquid flow caused by an elastic curved surface is investigated in the present article. To examine the effects of frictional heating on entropy generation, the energy dissipation function is included in the energy equation. The Tiwari and Dass model for nanofluid is used by taking water as a base fluid. A new class of nanofluid (hybrid nanofluid) with two kinds of nanoparticles, Copper (Cu) and Aluminum oxide (Al2O3), is considered. Curvilinear coordinates are used in the mathematical formulation due to the curved nature of the solid boundary. By utilizing similarity transformations, the modelled partial differential equations are converted into ordinary differential equations. Shooting and the Runge-Kutta-Fehlberg method (FRKM) have been used to solve the transformed set of non-linear differential equations. The expression for entropy generation is derived in curvilinear coordinates and computed by using the numerical results obtained from dimensionless momentum and energy equations. Comparisons of our numerical results and those published in the previous literature demonstrate excellent agreements, validating our numerical simulation. In addition, we have also conducted parametric studies and find that entropy generation and temperature suppress with increasing values of dimensionless radius of curvature. Furthermore, it is found that less entropy is generated in regular nanofluid as compare to hybrid nanofluid. To examine the influences of a set of embedding physical parameters on quantities of interest, different graphs are plotted and discussed.

scholarly journals Flow and heat transfer past a permeable stretching/shrinking sheet in Cu−Al2O3/water hybrid nanofluid

2019 ◽  
Vol 30 (3) ◽  
pp. 1197-1222 ◽  
Author(s):  
Rusya Iryanti Yahaya ◽  
Norihan M. Arifin ◽  
Roslinda Nazar ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Numerical Solutions ◽  
Skin Friction Coefficient ◽  
The Other ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Hybrid Nanofluid ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose The purpose of this paper is to study the flow and heat transfer of a hybrid nanofluid, Cu–Al2O3/water, past a permeable stretching/shrinking sheet. The effects of Brownian motion and thermophoresis are considered here. Design/methodology/approach Similarity transformations are used to reduce the governing partial differential equations to a system of ordinary (similarity) differential equations. A MATLAB solver called the bvp4c is then used to compute the numerical solutions of equations (12) to (14) subject to the boundary conditions of equation (15). Then, the effects of various physical parameters on the flow and thermal fields of the hybrid nanofluid are analyzed. Findings Multiple (dual) solutions are found for the basic boundary layer equations. A stability analysis is performed to see which solutions are stable and, therefore, applicable in practice and which are not stable. Besides that, a comparison is made between the hybrid nanofluid and a traditional nanofluid, Cu/water. The skin friction coefficient and Nusselt number of the hybrid nanofluid are found to be greater than that of the other nanofluid. Thus, the hybrid nanofluid has a higher heat transfer rate than the other nanofluid. However, the increase in the shrinking parameter reduces the velocity of the hybrid nanofluid. Originality/value The present results are original and new for the study of the flow and heat transfer past a permeable stretching/shrinking sheet in Cu–Al2O3/water hybrid nanofluid.

Stagnation-Point Flow over an Exponentially Shrinking/Stretching Sheet

2011 ◽  
Vol 66 (12) ◽  
pp. 705-711 ◽  
Author(s):  
Sin Wei Wong ◽  
Abu Omar Awang ◽  
Anuar Ishak
Keyword(s):  
Differential Equations ◽  
Stagnation Point ◽  
Stretching Sheet ◽  
Free Stream ◽  
Stagnation Point Flow ◽  
Stream Velocity ◽  
Heat Transfer Characteristics ◽  
Keller Box Method ◽  
Flow And Heat Transfer ◽  
Box Method

The steady two-dimensional stagnation-point flow of an incompressible viscous fluid over an exponentially shrinking/stretching sheet is studied. The shrinking/stretching velocity, the free stream velocity, and the surface temperature are assumed to vary in a power-law form with the distance from the stagnation point. The governing partial differential equations are transformed into a system of ordinary differential equations before being solved numerically by a finite difference scheme known as the Keller-box method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. It is found that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique.

Three-Dimensional Hybrid Nanofluid Flow and Heat Transfer past a Permeable Stretching/Shrinking Sheet with Velocity Slip and Convective Condition

2020 ◽  
Vol 66 ◽  
pp. 157-171 ◽  
Author(s):  
Najiyah Safwa Khashi'ie ◽  
Norihan Md Arifin ◽  
Ioan Pop ◽  
Roslinda Nazar ◽  
Ezad Hafidz Hafidzuddin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Shrinking Sheet ◽  
Hybrid Nanofluid ◽  
Convective Condition ◽  
Nanofluid Flow ◽  
Flow And Heat Transfer

Hybrid nanofluid flow and heat transfer past a vertical thin needle with prescribed surface heat flux

2019 ◽  
Vol 29 (12) ◽  
pp. 4875-4894 ◽  
Author(s):  
Iskandar Waini ◽  
Anuar Ishak ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat ◽  
Dual Solutions ◽  
Hybrid Nanofluid ◽  
Nanofluid Flow ◽  
Needle Size ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose The purpose of this paper is to study the steady mixed convection hybrid nanofluid flow and heat transfer past a vertical thin needle with prescribed surface heat flux. Design/methodology/approach The governing partial differential equations are transformed into a set of ordinary differential equations by using a similarity transformation. The transformed equations are then solved numerically using the boundary value problem solver (bvp4c) in Matlab software. The features of the skin friction coefficient and the local Nusselt number as well as the velocity and temperature profiles for different values of the governing parameters are analyzed and discussed. Findings It is found that dual solutions exist for a certain range of the mixed convection parameter where its critical values decrease with the increasing of the copper (Cu) nanoparticle volume fractions and for the smaller needle size. It is also observed that the increasing of the copper (Cu) nanoparticle volume fractions and the decreasing of the needle size tend to enhance the skin friction coefficient and the local Nusselt number on the needle surface. A temporal stability analysis is performed to determine the stability of the dual solutions in the long run, and it is revealed that only one of them is stable, while the other is unstable. Originality/value The problem of hybrid nanofluid flow and heat transfer past a vertical thin needle with prescribed surface heat flux is the important originality of the present study where the dual solutions for the opposing flow are obtained.

scholarly journals A Non-Newtonian Magnetohydrodynamics (MHD) Nanofluid Flow and Heat Transfer with Nonlinear Slip and Temperature Jump

Mathematics ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 1199 ◽  
Author(s):  
Jing Zhu ◽  
Yaxin Xu ◽  
Xiang Han
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Jump ◽  
Thin Sheet ◽  
Velocity Slip ◽  
Skin Friction Coefficient ◽  
Slip Condition ◽  
Physical Parameters ◽  
Nanofluid Flow ◽  
Flow And Heat Transfer

The velocity and thermal slip impacts on the magnetohydrodynamics (MHD) nanofluid flow and heat transfer through a stretched thin sheet are discussed in the paper. The no slip condition is substituted for a new slip condition consisting of higher-order slip and constitutive equation. Similarity transformation and Lie point symmetry are adopted to convert the derived governed equations to ordinary differential equations. An approximate analytical solution is gained through the homotopy analysis method. The impacts of velocity slip, temperature jump, and other physical parameters on flow and heat transfer are illustrated. Results indicate that the first-order slip and nonlinear slip parameters reduce the velocity boundary layer thickness and Nusselt number, whereas the effect on shear stress is converse. The temperature jump parameter causes a rise in the temperature, but a decline in the Nusselt number. With the increase of the order, we can get that the error reaches 10 − 6 from residual error curve. In addition, the velocity contours and the change of skin friction coefficient are computed through Ansys Fluent.

Effects of Unsteady Free-Stream Velocity and Free-Stream Turbulence at a Stagnation Point

1983 ◽  
Vol 105 (1) ◽  
pp. 66-71 ◽  
Author(s):  
R. S. R. Gorla
Keyword(s):  
Stagnation Point ◽  
Numerical Solutions ◽  
Free Stream ◽  
Eddy Diffusivity ◽  
Descent Method ◽  
Free Stream Velocity ◽  
Steepest Descent Method ◽  
Wall Friction ◽  
Stream Velocity ◽  
Free Stream Turbulence

An analysis is presented to investigate the combined effects of transient free-stream velocity and free-stream turbulence at a stagnation point on a cylinder situated in a crossflow. A model has been successfully formulated for the eddy diffusivity induced by the free-stream turbulence. The governing momentum equation has been integrated by the steepest descent method. Numerical solutions are provided for the unsteady wall shear stress function for specific free-stream transients. The results are correlated by a new turbulence parameter. It has been found that the wall friction increases with increasing free-stream turbulence intensity. In the case of flows involving unsteady free-stream velocity, the friction factor increases with increasing values of the reduced frequency of oscillations.

Sign in / Sign up

Export Citation Format

Share Document