393 publications from this institution
In this article, heat and mass transfer behavior of steady nanofluid flow between parallel plates in the presence of uniform magnetic field is studied. The important effect of Brownian motion and thermophoresis has been included in the model of nanofluid. The governing equations are solved via the Differential Transformation Method. The validity of this method was verified by comparison of previous work which is done for viscous fluid. The analysis is carried out for different parameters namely: viscosity parameter, Magnetic parameter, thermophoretic parameter and Brownian parameter. Results reveal that skin friction coefficient enhances with rise of viscosity and Magnetic parameters. Also it can be found that Nusselt number augments with an increase of viscosity parameters but it decreases with augment of Magnetic parameter, thermophoretic parameter and Brownian parameter.
Combined effects of nonlinear thermal radiation and cubic autocatalysis chemical reaction on the three dimensional flow of stretched nanofluid along a rotating sheet have been investigated in this paper. The flow field is assumed to be suspended with magnetic iron oxide nanoparticles (IONPs). Hamilton-Crosser model is applied to measure effective thermal conductivity of nanofluid. Rosseland approximation is employed to obtain the nonlinear radiative heat flux. For novelty and practical point of view, influence of fluctuating surface velocity and periodic surface temperature constraints are incorporated into the governing equations which in turn are made dimension free by employing suitable transformations. For numerical solutions, an explicit finite difference scheme has been proposed under the restrictions of derived stability conditions.
In this chapter, applications of new semianalytical methods are investigated. The names of these methods are the homotopy perturbation method, Galerkin optimal homotopy asymptotic method, differential transformation method, Adomian decomposition method, and homotopy analysis method. The chapter first discusses previous works and then presents the basic idea of each method. Also, the chapter provides sample Maple codes for these methods. Finally, several examples are provided in which semianalytical methods are used to simulate nanofluid flow and heat transfer in the presence of a magnetic field.
No abstract is provided for this article.
Utilizing renewable and alternative energy is the best way to confront endangering issues such as reduction of fossil fuels. Thermal energy storage systems can considerably reduce the consumption of energy and they can improve the utilizations of renewable energy sources. Recently, building section becomes a great consumer of heat causing to a great levels of carbon emission. For developing the energy output of the buildings, heat storage mixed with phase change material becomes an efficient technique. For enhancing the productivity, one of the techniques applied is storing heat whilst the time of great solar intensity and releasing it through the night time. Enhancement in the thermal conductivity leads the discharging time of PCM through the solidification to reduce. So, nanoparticles have been dispersed into paraffin in this article. In addition, considering wavy surface for the inner duct is taken into account as second way which is combined with first technique. Numerical approach was successfully verified and employed for various cases. The herein obtained outputs revealed that entropy generation is an augmenting function of amplitude of wavy surface and it is reducing function of concentration of nanomaterial. Also, dispersing nanomaterial is more effective when sinusoidal surface has been employed. Heat flux transfer to PCM declines as time progress. Discharging rate has been minimized as amplitude of wavy channel augments. Influences of amplitude of wavy surface are more pronounced in cases with pure paraffin.
Nanofluid flow and heat transfer in a rotating system is studied numerically using fourth-order Runge–Kutta method. The important effects of Brownian motion and thermophoresis have been included in the model of nanofluid. The numerical investigation is carried out for different governing parameters namely: Reynolds number, Rotation parameter, injection parameter, Schmidt number, Thermophoretic parameter and Brownian parameter. The results indicate that skin friction parameter increases with augment of Reynolds number and Rotation parameter but it decreases with increase of injection parameter. Also it can be found that Nusselt number has a direct relationship with Reynolds number and injection parameter while it has a reverse relationship with Rotation parameter, Schmidt number, Thermophoretic parameter and Brownian parameter.
Effect of spatially variable magnetic field on ferrofluid flow and heat transfer is investigated. The enclosure is filled with Fe3O4–water nanofluid. Control volume based finite element method (CVFEM) is applied to solve the governing equations. The combined effects of ferrohydrodynamic and magnetohydrodynamic have been taken into account. The influences of Magnetic number, Hartmann number, Rayleigh number and nanoparticle volume fraction on the flow and heat transfer characteristics have been examined. Results show that enhancement in heat transfer decrease with increase of Rayleigh number while for two other active parameters different behavior is observed. Also it can be concluded that Nusselt number is an increasing function of Magnetic number, Rayleigh number and nanoparticle volume fraction while it is a decreasing function of Hartmann number.
No abstract is provided for this article.
This research presents the outputs for nano-refrigerant (R600a/oil/CuO) boiling heat transfer within flattened channels utilizing experimental method. The influence of flattened percentage, flow rate, vapor quality as well as the mass fraction of CuO on boiling heat transfer (h) were discussed. Outcomes reveal that increasing the flattened percentage enhances the h. Also, within the ranges of present experiment, h augments by increasing nanoparticle’s concentration.
Present investigation involves study of thermal diffusion and heat generation effects on the unsteady magnetohydrodynamic flow of radiating and electrically conducting nanofluid past over an oscillating vertical plate through porous medium. Mathematical modeling of the problem gives rise to system of partial differential equations, and is solved analytically using Laplace transform. Effects of pertinent parameters on the fluid flow, heat and mass transfer characteristics have been studied graphically and the physical aspects are discussed in detail. With the help of velocity, temperature and concentration; Skin friction, Nusselt number and Sherwood number are derived and represented through tabular form.
Effect of static radial magnetic field on natural convection heat transfer in a horizontal cylindrical annulus enclosure filled with nanofluid is investigated numerically using the Lattice Boltzmann method (LBM). The inner and outer cylinder surfaces are maintained at the different uniform temperatures. The surfaces are non-magnetic material. The investigation is carried out for different governing parameters namely, Hartmann number, nanoparticle volume fraction and Rayleigh number. The effective thermal conductivity and viscosity of nanofluid are calculated using the Maxwell–Garnetts (MG) and Brinkman models, respectively. The results reveal that the flow oscillations can be suppressed effectively by imposing an external radial magnetic field. Also, it is found that the average Nusselt number is an increasing function of nanoparticle volume fraction and Rayleigh number, while it is a decreasing function of Hartmann number.
This research is about modeling the influence of Lorentz forces on Fe3O4–water nanofluid heat transfer enhancement in a permeable cavity. Shape factor influence on thermal conductivity of nanofluid is taken into consideration. Vorticity stream function formulation is utilized. The solutions of final equations are obtained by Control Volume based Finite Element Method. Graphs are shown for different values of radiation parameter ( Rd ) , Darcy number ( Da ) , nanofluid volume fraction ( ϕ ) , Rayleigh number ( Ra ) and Hartmann number ( Ha ) . Results indicate that heat transfer rate enhances with augment of Hartmann number. Selecting Platelet shaped nanoparticles leads to greatest heat transfer rate.
A comprehensive numerical investigation on natural convection of electrically conducting liquid metal flow and heat transfer characteristics in a wavy enclosure is presented. The control volume-based finite element method (CVFEM) has been adopted to solve numerically the governing conservation equations of mass, momentum, and energy by using a stream function vorticity formulation. Special attention is given to understand the effect of a transverse magnetic field on the heat transfer rate as well as flow configurations with different amplitudes of sinusoidal wall. The numerical procedure in this analysis yields consistent performance over a wide range of parameters; Hartmann number, Ha; Rayleigh number, Ra; dimensionless amplitude of sinusoidal wall, a, and a fixed Prandtl number (Pr = 0.025) for liquid metal. The results obtained are depicted in terms of streamlines and isotherms which show the significant effects of the Hartmann number on the fluid flow and temperature distribution inside the enclosure. It was found that the Nusselt number decreases with increase in the Hartmann number.
In this article, the Buongiorno model is applied to the investigation of nanofluid flow over a stretching plate in the presence of a magnetic field. Radiation and melting heat transfer are taken into account. The Runge-Kutta method is selected in order to solve the ODEs which are obtained from similarity transformations. The roles of the Brownian motion, thermophoretic parameter, Hartmann number, porosity parameter, melting parameter and Eckert number are presented graphically. Our results indicate that the nanofluid velocity and concentration are enhanced with a rise of the melting parameter. The Nusselt number is reduced with an increase of the porosity and melting parameters.
In current article, nanofluid time dependent heat transfer under the influence of Lorentz forces during discharging process is simulated by means of FEM. In order to overcome the limitation of PCM, NEPCM has been utilized. CuO and water are employed as nanoparticles and PCM. Brownian motion role is taken into consideration to estimate nanofluid characteristics. Graphs are illustrated as isotherm, solid fraction and stream line contours. Results reveal that discharging rate improves with augment of Lorentz forces. As Hartmann number augments, solid fraction profile will be converged in lower time. Dispersing nanoparticles has significant impact on phase change front.
In this paper, Homotopy perturbation method (HPM) has been applied to investigate the effect of magnetic field on Cu-water nanofluid flow in non-parallel walls. The validity of HPM solutions were verified by comparing with numerical results obtained using a fourth order Runge–Kutta method. Effects of active parameters on flow have been presented graphically. The results show that velocity in boundary layer thickness decreased with increase of Reynolds number and nanoparticle volume friction and increased with increasing Hartmann number.
Lattice Boltzmann method is used to investigate magnetohydrodynamic flow utilizing Cu–water nanofluid in a concentric annulus. This investigation was compared with other numerical methods and found to be in excellent agreement. Numerical results for flow and heat transfer characteristics are obtained for various values of Hartmann number (Ha =0 to 40), nanoparticle volume fraction (ϕ =0, 0.02, 0.04 and 0.06), Rayleigh number (Ra =104,105 and 106) and aspect ratio (λ =1.5 to 4.5). Results proved that enhancement ratio increases with decrease of Rayleigh number and it increases with augment of Hartmann number. Also it can be concluded that Nusselt number has a direct relationship with nanoparticle volume fraction, Rayleigh number and it has a reverse relationship with Hartmann number.
