scholarly journals Effects of Radiation and Eckert Number on MHD Flow with Heat Transfer Rate Near a Stagnation Point Over a Non-Linear Vertical Stretching Sheet

2020 ◽  
Vol 25 (1) ◽  
pp. 27-36
Author(s):  
O.J. Fenuga ◽  
A.R. Hassan ◽  
P.O. Olanrewaju

AbstractThis work investigates the effects of radiation and Eckert number on an MHD flow with heat transfer rate near a stagnation-point region over a nonlinear vertical stretching sheet. Using a similarity transformation, the governing equations are transformed into a system of ordinary differential equations which are solved numerically using the sixth order Runge-Kutta method with shooting technique. Tabular and graphical results are provided to examine the physical nature of the problem. Heat transfer rate at the surface decreases with radiation, Eckert number and as radiation increases, the flow temperature also increases for velocity ratio parameters ɛ <1 and ɛ >1.

2020 ◽  
Vol 25 (1) ◽  
pp. 37-51 ◽  
Author(s):  
O.J. Fenuga ◽  
A.R. Hassan ◽  
P.O. Olanrewaju

AbstractThis work investigates the mixed convection in a Magnetohydrodynamic (MHD) flow and heat transfer rate near a stagnation-point region over a nonlinear vertical stretching sheet. Using a similarity transformation, the governing equations are transformed into a system of ordinary differential equations which are solved numerically using the fourth order Runge-Kutta method with shooting technique. The influence of pertinent flow parameters on velocity, temperature, surface drag force and heat transfer rate are computed and analyzed. Graphical and tabular results are given to examine the nature of the problem. The heat transfer rate at the surface increases with the mixed convection.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
A. Malvandi ◽  
F. Hedayati ◽  
G. Domairry

This paper deals with the steady two-dimensional stagnation point flow of nanofluid toward an exponentially stretching sheet with nonuniform heat generation/absorption. The employed model for nanofluid includes two-component four-equation nonhomogeneous equilibrium model that incorporates the effects of Brownian diffusion and thermophoresis simultaneously. The basic partial boundary layer equations have been reduced to a two-point boundary value problem via similarity variables and solved analytically via HAM. Effects of governing parameters such as heat generation/absorption λ, stretching parameter ε, thermophoresis , Lewis number Le, Brownian motion , and Prandtl number Pr on heat transfer and concentration rates are investigated. The obtained results indicate that in contrast with heat transfer rate, concentration rate is very sensitive to the abovementioned parameters. Also, in the case of heat generation , despite concentration rate, heat transfer rate decreases. Moreover, increasing in stretching parameter leads to a gentle rise in both heat transfer and concentration rates.


2020 ◽  
Vol 30 (10) ◽  
pp. 4583-4606 ◽  
Author(s):  
Najiyah Safwa Khashi’ie ◽  
Norihan Md Arifin ◽  
Ioan Pop ◽  
Roslinda Nazar ◽  
Ezad Hafidz Hafidzuddin ◽  
...  

Purpose This paper aims to scrutinize the analysis of non-axisymmetric Homann stagnation point flow and heat transfer of hybrid Cu-Al2O3/water nanofluid over a stretching/shrinking flat plate. Design/methodology/approach The similarity transformation which fulfils the continuity equation is opted to transform the coupled momentum and energy equations into the nonlinear ordinary differential equations. Numerical solutions which are elucidated in the tables and graphs are obtained using the bvp4c solver. Findings Non-unique solutions (first and second) are feasible for both stretching and shrinking cases within the specific values of the parameters. First solution is the physical/real solution based on the execution of stability analysis. An upsurge of the ratio of the ambient fluid strain rate to the plate strain rate can delay the boundary layer separation, whereas a boost of the ratio of the ambient fluid shear rate to the plate strain rate only accelerates the separation of boundary layer. The heat transfer rate of hybrid nanofluid is greater for the stretching case than the shrinking case. However, for the shrinking case, the heat transfer rate intensifies with the increment of the copper (Cu) nanoparticles volume fraction, whereas a contrary result is found for the stretching case. Originality/value The present numerical results are original and new. It can contribute to other researchers on electing the relevant parameters to optimize the heat transfer process in the modern industry, and the right parameters to generate non-unique solution so that no misjudgment on flow and heat transfer features.


2020 ◽  
Vol 31 (09) ◽  
pp. 2050125
Author(s):  
Ahmed A. Afify ◽  
Nasser S. Elgazery

MHD viscoelastic (Walters’-B) fluid flow close to the stagnation point region along an extending plate with the changeable fluid properties’ influences has been debated. Heat transfer’s features are scrutinized via Cattaneo–Christov (CC) theory. The mathematical model for the physical problem is tackled numerically via Chebyshev pseudospectral (CPS) technique. The existing outcomes are supported by recent research and have acquired a suitable agreement. The numerical outcomes reveal that temperature fields are more pronounced for Fourier’s law case. Further, the opposite behavior is noticed with the heat transfer rate. Higher values of the conjugate parameter result in an increment of the heat transfer rate and temperature field. Fluid flow’s features, as well as physical quantities, are substantially varied via variable fluid properties.


Author(s):  
Caner Senkal ◽  
Shuichi Torii

The flow and heat transfer characteristics of laminar dual circular jet impinging on a heating plate with inclined confinement surface has been investigated numerically. Governing equations in steady state are solved by a control volume based finite-difference method. The simulations have been carried out for Reynolds number (250≤Re≤418), the angle of inclination of the confined upper wall (0 ≤ θ ≤ 10), circular jet to annular jet velocity ratio (0≤VR≤2) and jet to target plate distances between 2D and 8D where D is the outer diameter of dual jet.SIMPLE algorithm was used to obtain velocity and temperature fields. Hybrid difference scheme is adopted for the discretized terms in the governing equations. The discretised equations are solved iteratively using the tridiagonal matrix algorithm line solver. Heat transfer performance along the heated wall is amplified with an increase in the velocity ratio and the Reynolds number. On the contrary, a substantial reduction in the heat transfer rate, for VR = 0.0, occurs in the stagnation zone, because the absence of the inner nozzle injection causes the recirculation in the corresponding region. The heat transfer rate in the stagnation zone is attenuated by increasing the jet nozzle to impinging plate distance. In particular, the effect of the inclination angle in the down-stream region, especially at the vicinity of outlet, is major then other effects Nusselt number distribution on the impingement plate is affected by inclined upper wall because inclination of the wall accelerates the exhaust flow. The streamwise reduction in the heat transfer rate for θ = 0° is suppressed by the presence of the inclined confinement surface and its value is intensified by the inclination angle.


Author(s):  
Muhammad Khairul Anuar Mohamed ◽  
Siti Hanani Mat Yasin ◽  
Mohd Zuki Salleh ◽  
Hamzeh Taha Alkasasbeh

The present study investigated the magnetohydrodynamic (MHD) flow and heat transfer on a stagnation point past a stretching sheet in a blood-based Casson ferrofluid with Newtonian heating boundary conditions. The ferrite Fe3O4 and cobalt ferrite CoFe2O4 ferroparticles suspended into Casson fluid represent by human blood to form blood-based Casson ferrofluid are numerically examined. The mathematical model for Casson ferrofluid which is in non-linear partial differential equations are first transformed to a more convenient form by similarity transformation approach then solved numerically by using the Runge-Kutta-Fehlberg (RKF45) method. The characteristics and effects of the stretching parameter, the magnetic parameter, the Casson parameter and the ferroparticle volume fraction for Fe3O4 and CoFe2O4 on the variation of surface temperature and the reduced skin friction coefficient are analyzed and discussed. It is found that the blood-based Casson ferrofluid provided up to 46% higher in temperature surface compared to blood-based fluid with the presence of magnetic effects.


2018 ◽  
Vol 80 (3) ◽  
Author(s):  
Imran Ullah ◽  
Sharidan Shafie ◽  
Ilyas Khan

The dissipative flow of Casson fluid in the presence of heat generation and absorption is investigated. The flow is induced due to stretching wedge. The similarity transformations were used to to transformed the governing equations into ordinary differential equations. The transformed equations are solved numerically via Keller-box method. Numerical results for skin friction coefficient are compared and found in excellent agreement with published results. The effects of pertinent parameters on velocity and temperature profiles as well as skin friction and heat transfer rate are graphically displayed and analyzed. It is noticed that fluid velocity drops with the increase of Casson fluid and magnetic parameters when the wedge is stretching faster than free stream. It is also noted that the heat transfer rate at wedge surface reduces with the increase of Eckert number, whereas the reverse trend is noted in the case of Casson and radiation parameters. Moreover, with increasing of heat generation or absorption parameter the fluid temperature rises.


2018 ◽  
Vol 64 (4) ◽  
pp. 420 ◽  
Author(s):  
Abuzar Ghaffari ◽  
T. Javed ◽  
I. Mustafa

Non-linear thermal radiation effects on non-aligned stagnation point flow of Maxwell fluid have been carried out in the present investigation. It is observed that the non-linear radiation augments the temperature and heat transfer rate. This physical phenomenon is translated into a system of partial differential equations (PDEs). After useful transformation, these non-linear constitutive equations are transformed into a system of ordinary differential equations (ODEs) and interpreted numerically by means of parallel shooting technique. Effects of pertinent parameters on flow and heat transfer are elaborated through tables and graphs. It is observed that radiation and surface heating enhance the rate of heat transfer, however Prandtl number has inverse relation with thermal boundary layer thickness. It has been observed that for increasing Prandtl number, heat transfer rate enhances. The detailed discussion of heat transfer rate is also presented in this study. Flow pattern is judged through streamlines graphs. It is also observed that oblique stagnation point flow behaves like orthogonal stagnation point flow, when free stream velocity is very large as compared to stretching velocity.


2020 ◽  
Vol 9 (4) ◽  
pp. 293-301
Author(s):  
V. Rajesh ◽  
M. Srilatha ◽  
Ali J. Chamkha

In this paper, transient free convective boundary layer flow of a viscous hybrid nanofluid due to a vertical stretching sheet with MHD effects is studied numerically using the Crank Nicolson finite difference numerical technique. To explore the properties of heat transfer and the flow field due to a vertical stretching sheet in the existence of a Lorentz force, two different fluids, specifically Cu–Al2O3/water and Cu/water, are utilized. The results of different physical parameters and the practical quantities of concern that they affect are investigated. According to this article’s results, Cu–Al2O3/water has a superior heat transfer rate than Cu/water in a magnetic field setting. Various other nano mixtures can be attempted to attain the optimal heat transfer rate.


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