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Showing papers on "Combined forced and natural convection published in 2017"


Journal ArticleDOI
01 Jul 2017-Energy
TL;DR: In this paper, a thermal energy extrusion system was made by an improved parameters effect controlling method to promote the manufacturing economic efficiency, which is composed of activation energy electrical MHD Ohmic dissipation and mixed convection of a viscoelastic non-Newtonian Carreau-Nanofluid on a stagnation-point energy conversion problem.

337 citations


Journal ArticleDOI
TL;DR: In this article, a mesoscopic method is utilized to examine nanofluid forced convection in a three dimensional porous geometry in existence of uniform Lorentz forces, and the Lattice Boltzmann method is selected for this goal.

227 citations


Journal ArticleDOI
TL;DR: In this article, three dimensional simulations are presented by means of Lattice Boltzmann Method for nanofluid forced convection heat transfer in the presence of magnetic field.

174 citations


Journal ArticleDOI
TL;DR: In this paper, a review of the studies on natural convection heat transfer in triangular, trapezoidal, parallelogrammic enclosures and enclosures with curved and wavy walls filled with fluid or porous media is presented.

168 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of the presence of a heat sink and a heat source and their lengths and locations and the entropy generation on MHD mixed convection flow and heat transfer in a porous enclosure filled with a Cu-water nanofluid was investigated numerically.
Abstract: In this work, the effects of the presence of a heat sink and a heat source and their lengths and locations and the entropy generation on MHD mixed convection flow and heat transfer in a porous enclosure filled with a Cu-water nanofluid in the presence of partial slip effect are investigated numerically. Both the lid driven vertical walls of the cavity are thermally insulated and are moving with constant and equal speeds in their own plane and the effect of partial slip is imposed on these walls. A segment of the bottom wall is considered as a heat source meanwhile a heat sink is placed on the upper wall of cavity. There are heated and cold parts placed on the bottom and upper walls, respectively, while the remaining parts are thermally insulated. Entropy generation and local heat transfer according to different values of the governing parameters are presented in detail. It is found that the addition of nanoparticles decreases the convective heat transfer inside the porous cavity at all ranges of the heat ...

142 citations



Journal ArticleDOI
TL;DR: In this article, numerical simulation of mixed convection in a partitioned square cavity having CuO-Water nanofluid and superposed porous medium with an adiabatic rotating cylinder is performed.

127 citations


Journal ArticleDOI
TL;DR: A mathematical model has been developed to study the mixed convection on MHD flow of Casson fluid over a nonlinearly permeable stretching sheet with thermal radiation, viscous dissipation, heat source/sink, chemical reaction and suction as discussed by the authors.

107 citations


Journal ArticleDOI
TL;DR: In this paper, the authors deal with the magnetohydrodynamic mixed convection flow and heat as the consequence of a micropolar fluid past a heated or cooled stretching permeable surface by taking into account heat generation and absorption effects.

106 citations


Journal ArticleDOI
TL;DR: In this article, the characteristics of mixed convection flow of oldroyd-B nanoliquid are explored and computations are made to explore the characteristics and properties of the mixture of mixture of heat and mass transfer processes.
Abstract: Here modeling and computations are made to explore the characteristics of mixed convection flow of Oldroyd-B nanoliquid. Linear stretchable surface creates the flow. Brownian motion and thermophoretic aspects in nanoliquid modeling are retained. Thermal and solutal stratifications along with heat generation/absorption are considered for heat and mass transfer processes. Boundary layer approach is implemented in the mathematical formulation. The resulting problems are computed by homotopic algorithm. Salient features of Deborah numbers, mixed convection parameter, ratio of thermal to concentration buoyancy forces, Brownian motion parameter, Prandtl number, thermophoretic parameter, thermal/concentration stratification parameter, heat generation/absorption parameter and Schmidt number on the velocity, temperature, nanoparticles concentration and Nusselt and Sherwood numbers are reported through graphs and tables. Besides this the results of presented analysis have been compared with the available works in limiting situations and good agreement is noted.

100 citations


Journal ArticleDOI
TL;DR: In this paper, a lid-driven cavity with partially filled with a porous medium saturated with a ferrofluid has been analyzed numerically, and the governing partial differential equations formulated on the basis of a single-phase model for nanofluid, Brinkman-extended Darcy model for porous layer and Boussinesq approximation for buoyancy force have been solved by finite difference method of the second-order accuracy.

Journal ArticleDOI
TL;DR: In this paper, the influence of both thermal and solutal stratification on magneto-hydrodynamics (MHD) nanofluid flow along an exponentially stretching sheet is examined.
Abstract: The present analysis concentrates to examine the influence of both thermal and solutal stratification on magneto-hydrodynamics (MHD) nanofluid flow along an exponentially stretching sheet. Moreover, simultaneous effects of mixed convection and viscous dissipation are also analyzed to determine the thermal conductivity within the restricted domain. Energy and concentration equation consist of two important slip mechanisms, namely: the Brownian motion of nanoparticles and the thermophoresis due to concentration difference. By the mean of compatible similarity transformed, a system of PDEs is converted into the system of nonlinear ODEs. The resulting nonlinear ODEs are successfully solved via the implicit finite difference method (FDM). Obtained numerical solutions are plotted for each profile for different and converging values of including parameters. To validate the results, numerical values of Nusselt number are compared with the existing literature for a particular case. Obtained results present the significant impact of each parameter on temperature and concentration. Nanofluid flow behaviour is also observed via velocity profile.

Journal ArticleDOI
TL;DR: In this paper, an analytical approach for the non-Newtonian thin film nanofluids bioconvection based on physical mechanisms responsible for the nanoparticles and the base fluid, such as Brownian motion and thermophoresis, is presented.
Abstract: Mixed convection in gravity-driven non-Newtonian nanofluid films (Casson and Williamson) flow containing both nanoparticles and gyrotactic microorganisms along a convectively heated vertical surface is investigated. The actively controlled nanofluid model boundary conditions are used to explore the liquid films flow. The study exhibits an analytical approach for the non-Newtonian thin film nanofluids bioconvection based on physical mechanisms responsible for the nanoparticles and the base fluid, such as Brownian motion and thermophoresis. Both the fluids have almost the same behaviors for the effects of all the pertinent parameters except the effect of Schmidt number on the microorganism density function where the effect is opposite. Ordinary differential equations together with the boundary conditions are obtained through similarity variables from the governing equations of the problem, which are solved by HAM (Homotopy Analysis Method). The solution is expressed through graphs and illustrated which show the influences of all the parameters. The study is relevant to novel microbial fuel cell technologies combining the nanofluid with bioconvection phenomena.

Journal ArticleDOI
TL;DR: In this article, a similarity transformation is used to transform the constitutive equations into a system of nonlinear ordinary differential equations, and the resultant system of equations is then solved numerically using implicit finite difference method.

Journal ArticleDOI
TL;DR: In this article, the impacts of Joule heating and nonlinear radiation in mixed convective flow of Walter-B liquid are addressed and the governing mathematical problems are tackled via homotopic procedure.

Journal ArticleDOI
01 Aug 2017
TL;DR: In this paper, the shape effects on velocity profiles in radial, tangential, axial directions, and temperature distribution are displayed graphically with the reflection of specific range of nanolayer thickness and its conductivity.
Abstract: The aim of this paper is to study the different shapes of nanoparticles on mixed convective steady flow over a rotating disk. For nanofluid, the copper nanoparticles of disk, cylindrical, and spherical shapes of different sizes and water as base fluid are considered. The physical problem is first modeled and then the governing equations are transformed into nonlinear ordinary differential equations. These equations are dimensionless using geometrical and physical flowfield-dependent parameters and solved analytically. A very good agreement is observed between the obtained results of the current study and previously published study in limiting cases. The shape effects on velocity profiles in radial, tangential, axial directions, and temperature distribution are displayed graphically with the reflection of specific range of nanolayer thickness and its conductivity. In addition, irreversibility due to heat and fluid friction is investigated that supports the heat transfer enhancement in renewable energy syst...

Journal ArticleDOI
TL;DR: In this paper, the problem of unsteady mixed convection electrical magnetohydrodynamic (MHD) flow and heat transfer induced due to nanofluid over a permeable stretching sheet using Buongiorno model is investigated.

Journal ArticleDOI
TL;DR: In this article, the effects of various pertinent parameters such as Richardson number (between 0.05 and 50), elastic modulus of the side surfaces (between 1000 and 10 5 ), side wall inclination angle ( between 0° and 20°), and solid particle volume fraction (between 1 and 0.04) on the fluid flow and heat transfer characteristics in a 3D lid-driven trapezoidal cavity with nanofluids were numerically examined.

Journal ArticleDOI
TL;DR: In this article, mixed convection in alumina-water nanofluid filled lid-driven square cavity with an isothermally heated square blockage inside with magnetic field effect has been examined.

Journal ArticleDOI
TL;DR: In this article, the MHD two-dimensional flow of Eyring-Powell fluid with thermophoresis and Brownian motion is studied and the velocity, temperature and concentration gradients are also evaluated.

Journal ArticleDOI
TL;DR: In this paper, a numerical study of three-dimensional natural convection of air in a differentially heated cubical cavity with Rayleigh number (Ra) up to 10 10 is performed by using the recently developed coupled discrete unified gas-kinetic scheme.

Journal ArticleDOI
TL;DR: In this article, mixed convection of non-Newtonian nanofluid, using the Buongiorno's mathematical model in a cavity has been analyzed by Finite Difference Lattice Boltzmann method (FDLBM).

Journal ArticleDOI
Ahmed Rashad1
TL;DR: In this article, the problem of magnetohydrodynamic (MHD) mixed convection flow of Cobalt-kerosene ferrofluid adjacent a non-isothermal wedge under the influence of thermal radiation and partial slip was addressed.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effects of mixed convection of MHD flow in nanofluid filled and partially heated wavy walled lid-driven enclosure and found that the rate of heat transfer decreases with increasing the Hartmann number.

Journal ArticleDOI
TL;DR: In this article, the authors discussed the mixed convection three-dimensional boundary layer flow of upper-convected Maxwell fluid over a stretching surface with Cattaneo-Christov heat flux model.

Journal ArticleDOI
TL;DR: In this article, the authors considered magnetohydrodynamic Eyring-Powell nanofluid flow brought by an included stretching cylindrical surface under the region of stagnation point.
Abstract: In various attempts, researchers considered Eyring–Powell fluid flow past a flat stretching surface supported with different physical effects, but as yet few explorations are proposed with accuracy regarding cylindrical stretching surface. In this work, we have considered magnetohydrodynamic Eyring–Powell nanofluid flow brought by an included stretching cylindrical surface under the region of stagnation point. To report thermophysical aspects, Joule heating, thermal radiations, mixed convection, temperature stratification, and heat generation effects are taken into account. The flow conducting differential equations are fairly converted into system of coupled non-linear ordinary differential equations by means of appropriate transformation. A numerical communication is made against these obtained coupled equations through shooting method supported with fifth-order Runge–Kutta scheme. It is found that fluid temperature shows an inciting nature towards Eckert number, thermophoresis parameter, Brownian motion parameter, thermal radiation parameter, and heat generation parameter, but it reflects opposite trends for Lewis number and thermal stratification parameter. Furthermore, the obtained results are validated by providing comparison with existing values which set a benchmark of quality of computational algorithm.

Journal ArticleDOI
TL;DR: In this paper, an in-house parallel lattice Boltzmann code was developed to solve the problem in a 3D domain, and the results indicated that due to the fluid flow, heat transfer performance has an optimum point in Ha'�='200 where increasing S and Ra numbers only shows positive effects on Nu.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the physics of heat transfer mechanism in vertical cylindrical shell-and-tube latent heat thermal energy storage (LHTES) systems and applied a combined conduction/convection model to investigate the melted PCM's convective circulation.

Journal ArticleDOI
TL;DR: In this article, a comparative study of magnetohydrodynamic mixed convection boundary layer flow of Casson fluid brought by both flat and cylindrical stretching surfaces is reported, where the arising mathematically modelled partial differential equations are successfully converted into ordinary differential equations with the source of suitable transformation.

Journal ArticleDOI
TL;DR: In this paper, the three-dimensional mixed convection boundary layer flow of a nanofluid induced by an exponentially stretching sheet is numerically investigated in the presence of thermal radiation, heat source/sink and first-order chemical reaction effects.
Abstract: The three-dimensional mixed convection boundary layer flow of a nanofluid induced by an exponentially stretching sheet is numerically investigated in the presence of thermal radiation, heat source/sink and first-order chemical reaction effects. The adopted nanofluid model incorporates the effects of Brownian motion and thermophoresis into the mathematical model. The first-order velocity slip boundary conditions are also taken into account. The governing boundary layer equations are transformed into a set of nonlinear ordinary differential equations by employing suitable similarity variables. The resultant equations are solved numerically using the Runge-Kutta-Fehlberg method. Obtained solutions are compared with previous results in a limiting sense from the literature, demonstrating an excellent agreement. To show the typical trend of the solutions, a parametric study is conducted. The axial velocity, transverse velocity, temperature and nanoparticle volume fraction profiles as well as the skin-friction coefficient, Nusselt and Sherwood numbers are demonstrated graphically as a representative set of numerical results and discussed comprehensively.