Simulation of Fe3O4-H2O nanoliquid in a triangular enclosure subjected to Cattaneo–Christov theory of heat conduction

2019 ◽  
Vol 29 (11) ◽  
pp. 4430-4444 ◽  
Author(s):  
A.S. Dogonchi ◽  
Muhammad Waqas ◽  
M. Mudassar Gulzar ◽  
M. Hashemi-Tilehnoee ◽  
Seyyed Masoud Seyyedi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Conduction ◽  
Shape Factor ◽  
Design Methodology ◽  
Control Volume ◽  
Content Type ◽  
Controlling Element ◽  
Triangular Enclosure ◽  
Control Volume Finite Element ◽  
The Magnetic Field

Purpose The purpose of this research is to describe the importance of the Cattaneo–Christov theory of heat conduction in a triangular enclosure with a semi-circular heater. Analysis subjected to Fe3O4-H2O nanofluid is reported. Viscosity dependent on magnetic field is taken into consideration to simulate ferrofluid viscosity. Besides, heat generation and shape factor of nanoparticles are also considered. Design/methodology/approach The well-known control volume finite element method is used for simulations. Findings The outcomes reveal that the magnetic field can be introduced to the system as a controlling element. Originality/value No such analysis exists in the literature.

Research on magnetostriction of grain-oriented electrical silicon-steel sheet

2013 ◽  
Vol 33 (1/2) ◽  
pp. 28-37 ◽  
Author(s):  
Baodong Bai ◽  
Jiayin Wang
Keyword(s):  
Magnetic Field ◽  
Design Methodology ◽  
Steel Sheet ◽  
Rolling Direction ◽  
Great Influence ◽  
Silicon Steel ◽  
Field Direction ◽  
Magnetic Field Direction ◽  
Content Type ◽  
The Magnetic Field

Purpose – The magnetostriction of grain-oriented electrical silicon steel sheet is studied for the magnetic field direction along the rolling direction and deviating from it. The method of calculating the vibration of transformer is developed through COMSOL. The paper aims to discuss these issues. Design/methodology/approach – Measurements of signals of magnetostriction and magnetic polarization, and calculation through software. Findings – The angle between the magnetic field direction and the rolling direction does a great influence on magnetostriction strain. Originality/value – The maximum λ p-p of transversal magnetostriction is above 30 times more than the value when the angle is 0°. The transversal magnetostriction is a main reason of vibration increasing at the corner of transformer.

MHD natural convection of Cu/H2O nanofluid in a horizontal semi-cylinder with a local triangular heater

2018 ◽  
Vol 28 (12) ◽  
pp. 2979-2996 ◽  
Author(s):  
A.S. Dogonchi ◽  
Mikhail A. Sheremet ◽  
Ioan Pop ◽  
D.D. Ganji
Keyword(s):  
Magnetic Field ◽  
Rayleigh Number ◽  
Free Convection ◽  
Shape Factor ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Horizontal Cylinder ◽  
Content Type ◽  
Nanoparticles Volume Fraction

Purpose The purpose of this study is to investigate free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using control volume finite element method (CVFEM). Design/methodology/approach Governing equations formulated in dimensionless stream function, vorticity and temperature variables using the single-phase nanofluid model with Brinkman correlation for the effective dynamic viscosity and Hamilton and Crosser model for the effective thermal conductivity have been solved numerically by CVFEM. Findings The impacts of control parameters such as the Rayleigh number, Hartmann number, nanoparticles volume fraction, local triangular heater size, shape factor on streamlines and isotherms as well as local and average Nusselt numbers have been examined. The outcomes indicate that the average Nusselt number is an increasing function of the Rayleigh number, shape factor and nanoparticles volume fraction, while it is a decreasing function of the Hartmann number. Originality/value A complete study of the free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using CVFEM is addressed.

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.

Stabilised MLS in MLPG method for heat conduction problem

2019 ◽  
Vol 36 (4) ◽  
pp. 1323-1345
Author(s):  
Rituraj Singh ◽  
Krishna Mohan Singh
Keyword(s):  
Heat Conduction ◽  
Design Methodology ◽  
Heat Conduction Problem ◽  
Moving Least Squares ◽  
Moment Matrix ◽  
Content Type ◽  
Patch Tests ◽  
Mlpg Method ◽  
The One ◽  
Method Analysis

Purpose The purpose of this paper is to assess the performance of the stabilised moving least squares (MLS) scheme in the meshless local Petrov–Galerkin (MLPG) method for heat conduction method. Design/methodology/approach In the current work, the authors extend the stabilised MLS approach to the MLPG method for heat conduction problem. Its performance has been compared with the MLPG method based on the standard MLS and local coordinate MLS. The patch tests of MLS and modified MLS schemes have been presented along with the one- and two-dimensional examples for MLPG method of the heat conduction problem. Findings In the stabilised MLS, the condition number of moment matrix is independent of the nodal spacing and it is nearly constant in the global domain for all grid sizes. The shifted polynomials based MLS and stabilised MLS approaches are more robust than the standard MLS scheme in the MLPG method analysis of heat conduction problems. Originality/value The MLPG method based on the stabilised MLS scheme.

Nonlinear impedance boundary condition for 2D BEM

2018 ◽  
Vol 37 (2) ◽  
pp. 772-783 ◽  
Author(s):  
Carlo de Falco ◽  
Luca Di Rienzo ◽  
Nathan Ida ◽  
Sergey Yuferev
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Diffusion Equation ◽  
Efficient Implementation ◽  
Impedance Boundary Condition ◽  
Computational Domain ◽  
Impedance Boundary ◽  
Content Type ◽  
The Magnetic Field ◽  
Element Method

PurposeThe purpose of this paper is the derivation and efficient implementation of surface impedance boundary conditions (SIBCs) for nonlinear magnetic conductors. Design/methodology/approachAn approach based on perturbation theory is proposed, which expands to nonlinear problems the methods already developed by the authors for linear problems. Differently from the linear case, for which the analytical solution of the diffusion equation in the semi-infinite space for the magnetic field is available, in the nonlinear case the corresponding nonlinear diffusion equation must be solved numerically. To this aim, a suitable smooth map is defined to reduce the semi-infinite computational domain to a finite one; then the diffusion equation is solved by a Galerkin method relying on basis functions constructed via the push-forward of a Lagrangian polynomial basis whose degrees of freedom are collocated at Gauss–Lobatto nodes. The use of such basis in connection with a suitable under-integration naturally leads to mass-lumping without impacting the order of the method. The solution of the diffusion equation is coupled with a boundary element method formulation for the case of parallel magnetic conductors in terms of E and B fields. FindingsThe results are validated by comparison with full nonlinear finite element method simulations showing very good accordance at a much lower computational cost. Research limitations/implicationsLimitations of the method are those arising from perturbation theory: the introduced small parameter must be much less than one. This implies that the penetration depth of the magnetic field into the magnetic and conductive media must be much smaller than the characteristic size of the conductor. Originality/valueThe efficient implementation of a nonlinear SIBC based on a perturbation approach is proposed for an electric and magnetic field formulation of the two-dimensional problem of current driven parallel solid conductors.

A theoretical investigation for mixed convection impact in non-Newtonian nanofluid stratified flow subjected to magnetic field

2019 ◽  
Vol 29 (8) ◽  
pp. 2948-2963 ◽  
Author(s):  
Muhammad Waqas ◽  
Muhammad Mudassar Gulzar ◽  
Zeeshan Asghar ◽  
Z. Ali ◽  
Waqar Azeem Khan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Thermal Stratification ◽  
Design Methodology ◽  
Thermal Field ◽  
Second Grade ◽  
Second Grade Fluid ◽  
Nanofluid Flow ◽  
Content Type ◽  
Grade Fluid

Purpose The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade fluid are used for formulation. Magnetic field, heat absorption/generation and convective conditions are considered for modeling. Design/methodology/approach Convergent solutions are achieved using homotopy procedure. Findings The authors found opposing behavior for radiation and thermal stratification variables against thermal field. Originality/value No such analysis has yet been reported.

Investigation of micropolar hybrid ferrofluid flow over a vertical plate by considering various base fluid and nanoparticle shape factor

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kh. Hosseinzadeh ◽  
So Roghani ◽  
A. Asadi ◽  
Amirreza Mogharrebi ◽  
D.D. Ganji
Keyword(s):  
Magnetic Field ◽  
Shape Factor ◽  
Vertical Plate ◽  
Magnetic Parameter ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Nanoparticle Volume Fraction ◽  
Convection Heat ◽  
Content Type

Purpose The purpose of this paper is to investigate micropolar magnetohydrodynamics (MHD) fluid flow passing over a vertical plate. Three different base fluids have been used that include water, ethylene glycol and ethylene glycol/water (50%–50%). Also, a nanoparticle was used in all of the base fluids. The effects of natural convection heat transfer and magnetic field have been taken into account. Design/methodology/approach The main purpose of solving the governing equations is to scrutinize the effects of the magnetic parameter, the nanoparticle volume fraction, micropolar parameter and nanoparticles shape factor on velocity, temperature and microrotation profiles, the skin friction coefficient and the Nusselt number. These surveys have been considered for three base fluids simultaneously. Findings The results indicate that for water-based fluids, the temperature profile of lamina-shaped nanoparticles is 38.09% higher than brick-shaped nanoparticles. Originality/value This paper provides micropolar MHD fluid flow analysis considering natural convection heat transfer and magnetic field in three different base fluids. The aim of assessments is the diagnosis of some parameter effects, such as magnetic parameter and nanoparticle volume fraction, on velocity, temperature and microrotation profiles and components. Also, the use of mixed base fluids presented as a novelty in this paper.

Optimization of magnetic hat for quartz flexible accelerometer

Sensor Review ◽  
2016 ◽  
Vol 36 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Cuo Wang ◽  
Xingfei Li ◽  
Ke Kou ◽  
Chunguo Long
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Cylindrical Symmetry ◽  
Air Gap ◽  
Magnetic Sensors ◽  
Magnetic Field Distribution ◽  
Navigation Systems ◽  
Pole Piece ◽  
Content Type ◽  
The Magnetic Field

Purpose – This study aims to ameliorate the strength and uniformity of the magnetic field in the air-gap of quartz flexible accelerometers. Quartz flexible accelerometers (QFAs), a type of magneto-electric inertial sensors, have wide applications in inertial navigation systems, and their precision, linearity and stability performance are largely determined by the magnetic field in operation air-gap. To enhance the strength and uniformity of the magnetic field in the air-gap, a magnetic hat structure has been proposed to replace the traditional magnetic pole piece which tends to produce stratiform magnetic field distribution. Design/methodology/approach – Three-dimensional analysis in ANSYS workbench helps to exhibit magnetic field distribution for the structures with a pole piece and a magnetic hat, and under the hypothesis of cylindrical symmetry, two-dimensional finite element optimization by ANSYS APDL gives an optimal set of dimensions of the magnetic hat. Findings – Three structures of the QFA with a pole piece, a non-optimized magnetic hat and an optimized magnetic hat are compared by the simulation in ANSYS Maxwell and experiments measuring the electromagnetic rebalance force. The results show that the optimized hat can supply stronger and more uniform magnetic field, which is reflected by larger and more linear rebalance force. Originality/value – To the authors ' knowledge, the magnetic hat and its dimension optimization have rarely been reported, and they can find significant applications in designing QFAs or other similar magnetic sensors.

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