scholarly journals Effect of Velocity Slip Boundary Condition on the Flow and Heat Transfer of Cu-Water and TiO2-Water Nanofluids in the Presence of a Magnetic Field

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Abdelhalim Ebaid ◽  
Fahd Al Mutairi ◽  
S. M. Khaled
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Velocity ◽  
Velocity Slip ◽  
Slip Boundary Condition ◽  
Dual Solutions ◽  
Slip Condition ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Flow And Heat Transfer

In nanofluid mechanics, it has been proven recently that the no slip condition at the boundary is no longer valid which is the reason that we consider the effect of such slip condition on the flow and heat transfer of two types of nanofluids. The present paper considers the effect of the velocity slip condition on the flow and heat transfer of the Cu-water and the TiO2-water nanofluids over stretching/shrinking sheets in the presence of a magnetic field. The exact expression for the fluid velocity is obtained in terms of the exponential function, while an effective analytical procedure is suggested and successfully applied to obtain the exact temperature in terms of the generalized incomplete gamma function. It is found in this paper that the Cu-water nanofluid is slower than the TiO2-water nanofluid for both cases of the stretching/shrinking sheets. However, the temperature of the Cu-water nanofluid is always higher than the temperature of the TiO2-water nanofluid. In the case of shrinking sheet the dual solutions have been obtained at particular values of the physical parameters. In addition, the effect of various physical parameters on such dual solutions is discussed through the graphs.

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.

Dual Solutions in Magnetohydrodynamic Stagnation-Point Flow and Heat Transfer Over a Shrinking Surface With Partial Slip

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Tapas Ray Mahapatra ◽  
Samir Kumar Nandy ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Stagnation Point ◽  
Fluid Velocity ◽  
Velocity Slip ◽  
Stagnation Point Flow ◽  
Partial Slip ◽  
Shrinking Sheet ◽  
Slip Parameter ◽  
Similarity Transformations ◽  
Flow And Heat Transfer

In this paper, the problem of steady two-dimensional magnetohydrodynamic (MHD) stagnation-point flow and heat transfer of an incompressible viscous fluid over a stretching/shrinking sheet is investigated in the presence of velocity and thermal slips. With the help of similarity transformations, the governing Navier–Stokes and the energy equations are reduced to ordinary differential equations, which are then solved numerically using a shooting technique. Interesting solution behavior is observed for the similarity equations with multiple solution branches for certain parameter domain. Fluid velocity increases due to the increasing value of the velocity slip parameter resulting in a decrease in the temperature field. Temperature at a point increases with increase in the thermal slip parameter. The effects of the slips, stretching/shrinking, and the magnetic parameters on the skin friction or the wall shear stress, heat flux from the surface of the sheet, velocity, and temperature profiles are computed and discussed.

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

Effects of Second-Order Slip and Magnetic Field on Mixed Convection Stagnation-Point Flow of a Maxwellian Fluid: Multiple Solutions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
M. M. Rahman
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Reverse Flow ◽  
Second Order ◽  
Dual Solutions ◽  
Stagnation Point Flow ◽  
Shrinking Sheet ◽  
Variable Surface

In this paper, we investigate the effects of second-order slip and magnetic field on the nonlinear mixed convection stagnation-point flow toward a vertical permeable stretching/shrinking sheet in an upper convected Maxwell (UCM) fluid with variable surface temperature. Numerical results are obtained using the bvp4c function from matlab for the reduced skin-friction coefficient, the rate of heat transfer, the velocity, and the temperature profiles. The results indicate that multiple (dual) solutions exist for a buoyancy opposing flow for certain values of the parameter space irrespective to the types of surfaces whether it is stretched or shrinked. It is found that an applied magnetic field compensates the suction velocity for the existence of the dual solutions. Depending on the parametric conditions; elastic parameter, magnetic field parameter, first- and second-order slip parameters significantly controls the flow and heat transfer characteristics. The illustrated streamlines show that for upper branch solutions, the effects of stretching and suction are direct and obvious as the flow near the surface is seen to suck through the permeable sheet and drag away from the origin of the sheet. However, aligned but reverse flow occurs for the case of lower branch solutions when the mixed convection effect is less significant.

Magnetogasdynamic Flow and Heat Transfer in a Microchannel

2011 ◽  
Author(s):  
Huei Chu Weng
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Joule Heating ◽  
Electromagnetic Force ◽  
Gas Flow ◽  
Velocity Slip ◽  
Flow And Heat Transfer ◽  
Electric And Magnetic Field ◽  
Flow Through ◽  
Flow Drag

The presence of current flow in an electric and magnetic field results in electromagnetic force and joule heating. It is desirable to understand the roles of electromagnetic force and joule heating on gas microflow and heat transfer. In this study, a mathematical model is developed of the pressure-driven gas flow through a long isothermally heated horizontal planar microchannel in the presence of an external electric and magnetic field. The solutions for flow and thermal field and characteristics are derived analytically and presented in terms of dimensionless parameters. It is found that an electromagnetic driving force can be produced by a combined non-zero electric field and a negative magnetic field and results in an additional velocity slip and an additional flow drag. Also, a joule heating can be enhanced by an applied positive magnetic field and therefore results in an additional temperature jump and an additional heat transfer.

MHD flow and heat transfer of a magnetite–water nanofluid in porous medium under the effects of chemical reaction

2017 ◽  
Vol 14 (3) ◽  
pp. 193-199 ◽  
Author(s):  
Meysam Amini ◽  
Esmaeil GhasemiKafrudi ◽  
Mohammad Reza Habibi ◽  
Azin Ahmadi ◽  
Akram HosseinNia
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Chemical Reaction ◽  
Fluid Velocity ◽  
Mhd Flow ◽  
Industrial Applications ◽  
Temperature Fields ◽  
Stagnation Flow ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose Due to the extensive industrial applications of stagnation flow problems, the present work aims to investigate the magnetohydrodynamics (MHD) flow and heat transfer of a magnetite nanofluid (here Fe3O4–water nanofluid) impinging a flat porous plate under the effects of a non-uniform magnetic field and chemical reaction with variable reaction rate. Design/methodology/approach Similarity transformations are applied to reduce the governing partial differential equations with boundary conditions into a system of ordinary differential equations over a semi-infinite domain. The modified fourth-order Runge–Kutta method with the shooting technique which is developed for unbounded domains is conducted to give approximate solutions of the problem, which are then verified by results of other researchers, showing very good agreements. Findings The effects of the volume fraction of nanoparticles, permeability, magnetic field, chemical reaction and Schmidt number on velocity, temperature and concentration fields are examined and graphically illustrated. It was found that fluid velocity and temperature fields are affected strongly by the types of nanoparticles. Moreover, magnetic field and radiation have strong effects on velocity and temperature fields, fluid velocity increases and thickness of the velocity boundary layer decreases as magnetic parameter M increases. The results also showed that the thickness of the concentration boundary layer decreases with an increase in the Schmidt number, as well as an increase in the chemical reaction coefficient. Research limitations/implications The thermophysical properties of the magnetite nanofluid (Fe3O4–water nanofluid) in different conditions should be checked. Practical implications Stagnation flow of viscous fluid is important due to its vast industrial applications, such as the flows over the tips of rockets, aircrafts, submarines and oil ships. Moreover, nanofluid, a liquid containing a dispersion of sub-micronic solid particles (nanoparticles) with typical length of the order of 1-50 nm, showed abnormal convective heat transfer enhancement, which is remarkable. Originality/value The major novelty of the present work corresponds to utilization of a magnetite nanofluid (Fe3O4–water nanofluid) in a stagnation flow influenced by chemical reaction and magnetic field. It should be noted that in addition to a variable chemical reaction, the permeability is non-uniform, while the imposed magnetic field also varies along the sheet. These, all, make the present work rather original.

scholarly journals Unsteady Stagnation Point Flow of Hybrid Nanofluid Past a Convectively Heated Stretching/Shrinking Sheet with Velocity Slip

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1649
Author(s):  
Nurul Amira Zainal ◽  
Roslinda Nazar ◽  
Kohilavani Naganthran ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Skin Friction ◽  
Stagnation Point ◽  
Volume Fraction ◽  
Velocity Slip ◽  
Slip Condition ◽  
Stagnation Point Flow ◽  
Shrinking Sheet ◽  
Hybrid Nanofluid

Unsteady stagnation point flow in hybrid nanofluid (Al2O3-Cu/H2O) past a convectively heated stretching/shrinking sheet is examined. Apart from the conventional surface of the no-slip condition, the velocity slip condition is considered in this study. By incorporating verified similarity transformations, the differential equations together with their partial derivatives are changed into ordinary differential equations. Throughout the MATLAB operating system, the simplified mathematical model is clarified by employing the bvp4c procedure. The above-proposed approach is capable of producing non-uniqueness solutions when adequate initial assumptions are provided. The findings revealed that the skin friction coefficient intensifies in conjunction with the local Nusselt number by adding up the nanoparticles volume fraction. The occurrence of velocity slip at the boundary reduces the coefficient of skin friction; however, an upward trend is exemplified in the rate of heat transfer. The results also signified that, unlike the parameter of velocity slip, the increment in the unsteady parameter conclusively increases the coefficient of skin friction, and an upsurge attribution in the heat transfer rate is observed resulting from the increment of Biot number. The findings are evidenced to have dual solutions, which inevitably contribute to stability analysis, hence validating the feasibility of the first solution.

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