Thermal and Entropic Analysis of Viscous Fluid Flow in a Porous Channel With Convective Heat Transfer and Magnetic Field Aspects

Effects of using nanofluid, applying a magnetic field, and placing turbulators in channels on the convective heat transfer: A comprehensive review

Numerical investigations of the development and suppression of the natural convection flow and heat transfer in the presence of electromagnetic force

Effect of magnetic field on laminar convective heat transfer of magnetite nanofluids

Researchers in heat transfer field always attempt to find new solutions to optimize the performance of energy devices through heat transfer enhancement. Among various methods which are implemented to reinforce the thermal performance of energy systems, one is utilizing porous media in heat exchangers. In this study, characteristics of laminar mixed convection in a porous two-sided lid-driven square cavity induced by an internal heat generation at the bottom wall have been carried out by using a numerical methodology based on the finite volume method and the full multigrid acceleration. The two-sided and top walls of the enclosure are assumed to have cold temperature while the remaining walls of the bottom wall are insulated. The working fluid is air so that the Prandtl number equates 0.71. The behavior of different physical parameters is shown graphically so that computations have been conducted over a wide range of pertinent parameters; (10[Formula: see text] Ri [Formula: see text]), Darcy number ([Formula: see text] Da [Formula: see text]), internal Rayleigh number ([Formula: see text] Ra[Formula: see text]), the porosity ([Formula: see text]) and the Grashof number (10[Formula: see text] Gr [Formula: see text]). Results revealed that heat transfer mechanism and the flow characteristics inside the enclosure are strongly dependent on the Grashof number. For instance, the best heat transfer rates at the considered values of internal Rayleigh numbers are obtained for a high Grashof number. Furthermore, an increase of internal heat generation (RaI) leads to a higher flow and temperature intensities for Grashof numbers ranging from [Formula: see text] to [Formula: see text] and a specific Richardson number value. Besides, an increase in porosity values ([Formula: see text]) leads to an obvious decrease in the average Nusselt number. Maximum temperature [Formula: see text] is optimal for high ([Formula: see text]) value. A correlation expression for the average Nusselt number relative to the internal heat source was established in function of two control parameters such as Darcy and Richardson numbers.

Transient temperature distributions within spherical products with internal heat generation and transpiration: experimental and analytical results

Effect of magnetic field on the hydrodynamic and heat transfer of magnetite ferrofluid flow in a porous fin heat sink

Convective heat transfer in porous channel with multi-layer fractures under Local thermal non-equilibrium condition

CFD modeling and sensitivity analysis of heat transfer enhancement of a ferrofluid flow in the presence of a magnetic field

The numerous industrial and engineering applications of Casson nanofluid is due to the superiority of its thermophysical properties. Tomatoes paste, engine oil, soup etc., are examples of Casson fluid and when nanometer-sized particles are suspended in such Casson fluid, it becomes Casson nanofluid. This paper considers a natural convective magnetohydrodynamics flow of Cu-engine oil nanofluid across a convectively heated vertical plate. The effects of self-heating of the fluid (measured by the Eckert number), internal conductive resistance to external convective resistance (measured by the Biot number), magnetic field strength, volume fraction of the nanoparticles on the temperature and velocity of mass and heat transfer of Casson nanofluid is analysed. An appropriate model governing the flow of Casson nanofluid is formulated as a system of nonlinear partial differential equations. The natural convection boundary condition is included. To solve the problem, an appropriate similarity transformation is used to reformulate the system as a system of nonlinear ordinary differential equations. The shooting technique is used to convert the boundary problem to initial value problems before Runge-Kutta method, with the Gills constants, is used to solve the reformulated problem. The results are depicted as graphs. Flow velocity is found to increase as the base fluid becomes more Casson and as nanoparticle volume fraction increases. It is also found that increasing Eckert number, Biot number and magnetic field strength causes an increase in the flow temperature.

This paper studies the convective heat transfer and flow resistance of Fe3O4/deionized water nanofluids in laminar flow under the control of an external magnetic field. The basic thermophysical parameters including viscosity, specific heat capacity and thermal conductivity are investigated to describe the fundamental performance of heat transfer and flow resistance. In the absence of the magnetic field, the heat transfer coefficients and flow friction could not change significantly at nanoparticle volume concentration of 0.05%. In the presence of the magnetic field, it can enhance heat transfer and flow resistance by 6% and 3.5% when the magnets interlace on both sides of the tube. The dynamic magnetic experiments discussed the heat transfer increase process in detail. The heat transfer and the flow resistance increase by 11.7% and 5.4% when magnetic field strength is 600 Gs, nanoparticle volume concentration is 2% and Reynolds number is 2000. The radial shuttle movement of magnetic nanoparticles in the cross-section, micro convection in base fluid and the slip velocity between the nanoparticles and the base fluid are considered the main reasons for heat transfer enhancement.

An experimental investigation on the enhancement of convective heat transfer of a flat plate and LED using ionic wind is reported. The natural and forced convection heat transfers were considered. The ionic wind describes the generation of airflow between two electrodes held at a potential difference and is known to enhance heat transfer. An in-depth review of literatures is provided, where the enhancement of heat transfer is attributed to the generation of secondary flow and disruption of existing boundary layer. Two experimental setups have been constructed, for the natural convection heat transfer enhancement of a flat plate and for the forced convection heat transfer enhancement of LED. The bulk flow forced convection of the LED was generated by an axial fan. For the investigation with the flat plate, the parameters involved were the applied voltage to generate the ionic wind, the flat plate heat flux, the separation gap of electrodes and the number of emitter electrodes used. As the applied voltage increased, the enhancement increased. While as the flat plate heat flux increased, the enhancement of ionic wind decreased due to overwhelming effects of buoyancy. With separation gaps of g = 1.5 cm and g = 1.75 cm, the ionic wind produced similar enhancements, while the heat transfer enhancement was lower with a separation gap of g = 2 cm. Increasing the number of emitter electrodes did not increase the enhancement as the enhancement was linked to the corona current. The maximum heat transfer enhancement recorded was η = 1.41. For the enhancement of heat transfer of the LED, the parameters investigated were the bulk flow velocity represented by the Reynolds number and the orientation of electrodes relative to the LED. In the laminar flow regime investigated, the effect of the Reynolds number on the heat transfer enhancement was minimum. At a given low power consumption, the ionic wind enhanced setup produced a lower average heat transfer coefficient as compared to those produced by the setup cooled solely by the axial fan. This was due to the significant heat transfer produced by the axial fan at low power. However, as the total consumption of power increased, the heat transfer enhancement of the ionic wind increased beyond the reach of the setup with axial fan. The maximum heat transfer enhancement of the LED was η = 1.38. An analysis of the electrodes geometry was performed and showed that the enhancement of heat transfer was dependent on the orientation of the electrodes relative to the LED. An average Nusselt number correlation was formed.

Purpose The purpose of this paper is to study the natural convection and radiation heat transfer inside Nonagon inclined cavity with variable heated source length, which contains a porous medium saturated with nanofluid in the presence of uniform heat generation or absorption under the effect of uniform magnetic field with variable direction. The shape factor of nano particles is taking account for the model of nanofluid. Design/methodology/approach This study is established in two-dimensional space. The 2D numerical study is effectuated with Comsol Multiphysics based on the on the finite element method. The 2D equation system is exposed on dimensionless form taking into account the boundary conditions. Findings Results obtained show that the convection heat transfer is ameliorated with the augmentation of heated source length. The convection heat transfer is enhanced by increasing Rayleigh, Darcy numbers and the heated source length; however, it is reduced by rising Hartmann number. The presence of radiation parameter lead to improve the convection heat transfer in the presence of both uniform heat generation/absorption. The average Nusselt number reaches a maximum for an inclination of cavity γ = 45° and a minimum for γ = 60°. Both the increase of the shape factor of nano particles and the solid fraction of nano particles improve the convection heat transfer. Originality/value Different studies have been realized to study the heat transfer inside cavity contains porous medium saturated with nanofluid under magnetic field effect. In this work, the Nonagon geometric of cavity studied has never been studied. In addition, the effect of radiation parameter with relation of the shape factor of nanoparticles in the presence of uniform heat generation/absorption on the heat transfer performance have never been investigated. Also, the effect of magnetic field direction with relation of the inclination cavity on heat transfer performance.

Magnetocontrollable convective heat transfer of nanofluid through a straight tube

Effect of thermal buoyancy on flow and heat transfer around a permeable circular cylinder with internal heat generation

Multi-physics analysis of squeezing fluid flow with rotational, magnetic field, and heat transfer interactions