scholarly journals Numerical Simulation of Free Convection Heat Transfer of Ferrofluid in an Oval Shaped Closed Loop

2018 ◽  
Vol 7 (2) ◽  
pp. 43-47
Author(s):  
Jaswinder Singh Mehta ◽  
Rajesh Kumar
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Permanent Magnet ◽  
Applied Magnetic Field ◽  
Closed Loop ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Maximum Velocity ◽  
Free Convection Heat ◽  
Spatially Varying

Free convective heat transfer capability of kerosene based ferrofluid flowing through an oval shaped two-dimensional closed loop has been investigated numerically. COMSOL Multi Physics, a standard CFD code has been applied for solving the governing equations. A constant magnetic field was applied using permanent magnet and time dependent numerical study has been conducted for laminar fluid flow and heat transfer. The fluid was found to flow under the effect of externally applied magnetic field and spatially varying temperature. Maximum velocity of 4.43 mm/s has been found under the influence of externally applied magnetic field generated by the permanent magnet and flow was observed to be continuous. Temperature and velocity plots have also been plotted reconfirming the candidature of ferrofluid as a coolant for heat transfer applications of mini/micro devices.

Magnetohydrodynamic effects on flow structures and heat transfer over two cylinders wrapped with a porous layer in side

2016 ◽  
Vol 26 (5) ◽  
pp. 1416-1432 ◽  
Author(s):  
Saman Rashidi ◽  
Javad Abolfazli Esfahani ◽  
Mohammad Sadegh Valipour ◽  
Masoud Bovand ◽  
Ioan Pop
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Flow Field ◽  
Porous Layer ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Circular Cylinders ◽  
Flow Structures ◽  
Content Type ◽  
The Magnetic Field

Purpose – The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor safety analysis, combustion, compact heat exchangers, solar power collectors, high-performance insulation for buildings and many another applications. The purpose of this paper is to perform a numerical study on flows passing through two circular cylinders in side-by-side arrangement wrapped with a porous layer under the influence of a magnetic field. The authors focus the attention to the effects of magnetic field, Darcy number and pitch ratio on the mechanism of convection heat transfer and flow structures. Design/methodology/approach – The Darcy-Brinkman-Forchheimer model for simulating the flow in porous medium along with the Maxwell equations for providing the coupling between the flow field and the magnetic field have been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Stuart and Darcy numbers are varied within the range of 0 < N < 3 and 1e-6 < Da < 1e-2, respectively, and Reynolds and Prandtl numbers are equal to Re=100 and Pr=0.71, respectively. Findings – The results show that the drag coefficient decreases for N < 0.6 and increases for N > 0.6. Also, the effect of magnetic field is negligible in the gap between two cylinders because the magnetic field for two cylinders counteracts each other in these regions. Originality/value – To the authors knowledge, in the open literature, flow passing over two circular cylinders in side-by-side arrangement wrapped with a porous layer has been rarely investigated especially under the influence of a magnetic field.

scholarly journals Numerical study on laminar free convection heat transfer between sphere particle and high pressure water in pseudo-critical zone

2014 ◽  
Vol 18 (4) ◽  
pp. 1293-1303 ◽  
Author(s):  
Liping Wei ◽  
Youjun Lu ◽  
Jinjia Wei
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Free Convection ◽  
Fluidized Bed ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Boussinesq Approximation ◽  
Convection Heat ◽  
Pressure Water ◽  
Free Convection Heat

Supercritical water fluidized bed reactor (SCWFBR) is a promising new reaction vessel which can effectively gasify wet biomass and efficiently produce hydrogen. Free convection heat transfer from particle in supercritical water (SCW) is a major basic heat transfer mechanism in a fixed bed or fluidized bed with low superficial velocity. In this paper, numerical study on the steady free convection heat transfer around single sphere particle in high pressure water of pseudo-critical zone was carried out. Both the Boussinesq approximation method and real properties model (considering variable specific heat, density, viscosity, and conductivity of SCW) were incorporated to simulate the flow and temperature field. With respect to Boussinesq approximation, real properties model shows higher vorticity and temperature gradients in the vicinity of the sphere surface, which shows variation of thermo-physical property has remarkable effect on the free convection heat transfer process. High local Nusselt number and high heat transfer rate were observed with real properties model.

Numerical Study of Magnetic Field Effects on Buoyancy Driven Convection in a Non-Isothermally Heated Square Enclosure

2011 ◽  
Vol 312-315 ◽  
pp. 536-541
Author(s):  
Ghanbar Ali Sheikhzadeh ◽  
Mohsen Pirmohammadi ◽  
A. Fattahi ◽  
M.A. Mehrabian
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Hartmann Number ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Magnetic Field Effects ◽  
Left Wall ◽  
Square Enclosure ◽  
The Right ◽  
Sinusoidal Function

Numerical simulation of natural convection heat transfer in the presence of a magnetic field is analyzed in a non-isothermally heated square enclosure. The left wall is heated and cooled with a sinusoidal heat source and the right wall is cooled isothermally. The horizontal walls of the enclosure are adiabatic. The effects of Rayleigh number (Ra = 104, 105 and 106), Hartmann number (Ha = 0, 25, 50 and 100) and amplitude of sinusoidal function (n = 0.25, 0.5 and 1) on temperature and flow fields are analyzed. It is observed that the rate of heat transfer is decreased with increasing the Hartmann number; it is also decreased when decreasing the amplitude of sinusoidal function.

Magnetic Field Dependent (MFD) Viscosity Effect on Nanofluid Treatment

2018 ◽  
pp. 556-641
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Control Volume ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Viscosity Effect ◽  
Viscosity Parameter ◽  
Field Dependent ◽  
Free Convection Heat ◽  
Mfd Viscosity

In this chapter, the effect of magnetic field dependent (MFD) viscosity on free convection heat transfer of nanofluid in an enclosure is investigated. A single-phase nanofluid model is utilized considering Brownian motion. The control volume-based finite element method is applied to simulate this problem. The effects of viscosity parameter, Hartmann number, and Rayleigh number on hydrothermal behavior have been examined.

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