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Article
Publication date: 28 August 2019

R. Ellahi, Sadiq M. Sait, N. Shehzad and Z. Ayaz

The purpose of this paper is to present the investigation of the pressure-driven flow of aluminum oxide-water based nanofluid with the combined effect of entropy…

Abstract

Purpose

The purpose of this paper is to present the investigation of the pressure-driven flow of aluminum oxide-water based nanofluid with the combined effect of entropy generation and radiative electro-magnetohydrodynamics filled with porous media inside a symmetric wavy channel.

Design/methodology/approach

The non-linear coupled differential equations are first converted into a number of ordinary differential equations with appropriate transformations and then analytical solutions are obtained by homotopic approach. Numerical simulation has been designed by the most efficient approach known homotopic-based Mathematica package BVPh 2.0 technique. The long wavelength approximation over the channel walls is taken into account. The obtained analytical results have been validated through graphs to infer the role of most involved pertinent parameters, whereas the characteristics of heat transfer and shear stress phenomena are presented and examined numerically.

Findings

It is found that the velocity profile decreases near to the channel. This is in accordance with the physical expectation because resistive force acts opposite the direction of fluid motion, which causes a decrease in velocity. It is seen that when the electromagnetic parameter increases then the velocity close to the central walls decreases whereas quite an opposite behavior is noted near to the walls. This happens because of the combined influence of electro-magnetohydrodynamics. It is perceived that by increasing the magnetic field parameter, Darcy number, radiation parameter, electromagnetic parameter and the temperature profile increases, and this is because of thermal buoyancy effect. For radiation and electromagnetic parameters, energy loss at the lower wall has substantial impact compared to the upper wall. Residual error minimizes at 20th order iterations.

Originality/value

The proposed prospective model is designed to explore the simultaneous effects of aluminum oxide-water base nanofluid, electro-magnetohydrodynamics and entropy generation through porous media. To the best of author’s knowledge, this model is reported for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 19 September 2016

Yue Ji, Xingfei Li, Tengfei Wu, Cheng Chen and Ying Yang

The evaluations of the magnetohydrodynamics angular rate sensor (MHD ARS) in its applications necessitate further improvements in the sensor’s dynamic measurement ability…

Abstract

Purpose

The evaluations of the magnetohydrodynamics angular rate sensor (MHD ARS) in its applications necessitate further improvements in the sensor’s dynamic measurement ability. The magnetic field of the MHD ARS is a key factor in the sensor’s modeling and error analysis. The aim of this study is to illustrate the influence of a non-uniform magnetic field on the sensor.

Design/methodology/approach

Numerical simulation is made using ANSYS FLUNET with the magnetic field calculated by 3D-Magnetostatic. The comparison of the simulation results between uniform and non-uniform magnetic fields is made to reveal and explain the effects of magnetic field inhomogeneity (MFI) on the flow and electric field in detail. Two different structures with different MFIs are designed to confirm the MFI effect on the sensor’s output in simulation and experiment. A cross-correlation experiment and an adaptive filter are carried out to extract the signal to identify the error of the sensor output caused by MFI.

Findings

The MFI effect on the flow field in MHD ARS is found to be insignificant, while its effect on the electric potential is considerable. The comparisons between two kinds of MHD ARS in numerical simulation and experiment show that the MFI effect on the sensor error can be identified by fitting the sensor output. The deviation is mainly generated at the peaks and valleys of an angular vibration.

Originality/value

The study of the MHD ARS under the influence of a non-uniform magnetic field can offer an understanding of the MFI effect on the sensor and an evaluation method of the sensor error caused by the MFI effect.

Details

Sensor Review, vol. 36 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Article
Publication date: 21 March 2016

Yue Ji, Xingfei Li, Tengfei Wu and Cheng Chen

Magnetohydrodynamics angular regular sensor (MHD ARS) has been used in many applications for its low noise in wide bandwidth, impact resistance and low power consumption;…

Abstract

Purpose

Magnetohydrodynamics angular regular sensor (MHD ARS) has been used in many applications for its low noise in wide bandwidth, impact resistance and low power consumption; however, it is unable to estimate the angular velocity at low frequencies such as below 1 Hz. It is difficult to design compensation methods without an exact model. The aim of this study is to investigate a more exact analytical model characterization of the sensor’s frequency response, especially at a low-frequency zone.

Design/methodology/approach

A correction coefficient of electromagnetic force in simplified MHD ARS model was introduced according to the theoretical analysis of MHD flow and it was obtained by numerical simulation of electromagnetic force varying with time, space structure and frequency.

Findings

To make comparison, the transfer function of the designed MHD ARS in the experiment was identified using Gauss–Newton method with reasonable weights. The identification results confirmed the analytical model. Furthermore, a digital filter was designed based on the analytical model, and the compensation results showed that the frequency limit at low-frequency side was extended from 1 to 0.01 Hz.

Originality/value

The modified analytical model can describe the MHD ARS’s frequency response exactly and may be applied in its low-frequency compensation.

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Article
Publication date: 18 April 2019

Abiodun O. Ajibade and Jeremiah Jerry Gambo

The purpose of this paper is to analyze magnetohydrodynamics fully developed natural convection heat-generating/absorbing slip flow through a porous medium. Adomian…

Abstract

Purpose

The purpose of this paper is to analyze magnetohydrodynamics fully developed natural convection heat-generating/absorbing slip flow through a porous medium. Adomian decomposition method was applied to find the solutions to the problem.

Design/methodology/approach

In this study, Adomian decomposition method was used.

Findings

Results show that heat generation parameter enhanced the temperature and velocity of the fluid in the annulus. Moreover, slip effect parameter increases the velocity of the fluid.

Originality/value

Originality is in the application of Adomian decomposition method which allowed the slip at interface.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

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Article
Publication date: 6 August 2018

K. Ramesh and M. Devakar

The main purpose of this paper is to study the effect of heat transfer on the peristaltic flow of a magnetohydrodynamic Walters B fluid through a porous medium in an…

Abstract

Purpose

The main purpose of this paper is to study the effect of heat transfer on the peristaltic flow of a magnetohydrodynamic Walters B fluid through a porous medium in an inclined asymmetric channel.

Design/methodology/approach

The approximate analytical solutions of the governing partial differential equations are obtained using the regular perturbation method by taking wave number as a small parameter. The solutions for the pressure difference and friction forces are evaluated using numerical integration.

Findings

It is noticed that the pressure gradient and pressure difference are increasing functions of inclination angle and Grashof number. The temperature and heat transfer coefficients both increase with increase in inclination angle, Darcy number, Grashof number and Prandtl number. Increase in Hartmann number and phase difference decreases the size of trapped bolus.

Originality/value

The problem is original, as no work has been reported on the effect of magnetohydrodynamics on the peristaltic flow of a Walters B fluid through a porous medium in an inclined asymmetric channel with heat transfer.

Details

World Journal of Engineering, vol. 15 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 4 September 2018

Qili Tang

The purpose of this paper is to design a parallel finite element (FE) algorithm based on fully overlapping domain decomposition for solving the nonstationary…

Abstract

Purpose

The purpose of this paper is to design a parallel finite element (FE) algorithm based on fully overlapping domain decomposition for solving the nonstationary incompressible magnetohydrodynamics (MHD).

Design/methodology/approach

The fully discrete Euler implicit/explicit FE subproblems, which are defined in the whole domain with vast majority of the degrees of freedom associated with the particular subdomain, are solved in parallel. In each subproblem, the linear term is treated by implicit scheme and the nonlinear term is solved by explicit one.

Findings

For the algorithm, the almost unconditional convergence with optimal orders is validated by numerical tests. Some interesting phenomena are presented.

Originality/value

The proposed algorithm is effective, easy to realize with low communication costs and preferred for solving the strong nonlinear MHD system.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 23 November 2018

K. Ramesh and Sartaj Ahmad Eytoo

The purpose of this paper is to investigate the three fundamental flows (namely, both the plates moving in opposite directions, the lower plate is moving and other is at…

Abstract

Purpose

The purpose of this paper is to investigate the three fundamental flows (namely, both the plates moving in opposite directions, the lower plate is moving and other is at rest, and both the plates moving in the direction of flow) of the Ree-Eyring fluid between infinitely parallel plates with the effects of magnetic field, porous medium, heat transfer, radiation and slip boundary conditions. Moreover, the intention of the study is to examine the effect of different physical parameters on the fluid flow.

Design/methodology/approach

The mathematical modeling is performed on the basis of law of conservation of mass, momentum and energy equation. The modeling of the present problem is considered in Cartesian coordinate system. The governing equations are non-dimensionalized using appropriate dimensionless quantities in all the mentioned cases. The closed-form solutions are presented for the velocity and temperature profiles.

Findings

The graphical results are presented for the velocity and temperature distributions with the pertinent parameters of interest. It is observed from the present results that the velocity is a decreasing function of Hartmann number. Temperature increases with the increase of Ree-Eyring fluid parameter, radiation parameter and temperature slip parameter.

Originality/value

First time in the literature, the authors obtained closed-form solutions for the fundamental flows of Ree-Erying fluid between infinitely parallel plates with the effects of magnetic field, porous medium, heat transfer, radiation and slip boundary conditions. Moreover, the results of this paper are new and original.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

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Article
Publication date: 6 June 2016

R Ellahi, E Shivanian, S Abbasbandy and T. Hayat

The purpose of this paper is to study the generalized Couette flow of Eyring-Powell fluid. The paper aims to discuss diverse issues befell for the heat transfer…

Abstract

Purpose

The purpose of this paper is to study the generalized Couette flow of Eyring-Powell fluid. The paper aims to discuss diverse issues befell for the heat transfer, magnetohydrodynamics and slip.

Design/methodology/approach

A hybrid technique based on pseudo-spectral collocation is applied for the solution of nonlinear resulting system.

Findings

Viscous fluid results which are yet not available can be taken as a limiting case of presented problem. The results for the case of Hartmann flow can be obtained as a special case when plate velocity is zero, i.e. pressure gradient induced flow. The results for the zero fluid slip and no thermal slip also become special cases of this work, and the results can be recovered by setting, and to zero. These solutions are valid not only for small but also for large values of all emerging parameters.

Originality/value

This model is investigated for the first time, as the authors know.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 25 February 2021

Leo Lukose and Tanmay Basak

The purpose of this paper is to address various works on mixed convection and proposes 10 unified models (Models 1–10) based on various thermal and kinematic conditions of…

Abstract

Purpose

The purpose of this paper is to address various works on mixed convection and proposes 10 unified models (Models 1–10) based on various thermal and kinematic conditions of the boundary walls, thermal conditions and/ or kinematics of objects embedded in the cavities and kinematics of external flow field through the ventilation ports. Experimental works on mixed convection have also been addressed.

Design/methodology/approach

This review is based on 10 unified models on mixed convection within cavities. Models 1–5 involve mixed convection based on the movement of single or double walls subjected to various temperature boundary conditions. Model 6 elucidates mixed convection due to the movement of single or double walls of cavities containing discrete heaters at the stationary wall(s). Model 7A focuses mixed convection based on the movement of wall(s) for cavities containing stationary solid obstacles (hot or cold or adiabatic) whereas Model 7B elucidates mixed convection based on the rotation of solid cylinders (hot or conductive or adiabatic) within the cavities enclosed by stationary or moving wall(s). Model 8 is based on mixed convection due to the flow of air through ventilation ports of cavities (with or without adiabatic baffles) subjected to hot and adiabatic walls. Models 9 and 10 elucidate mixed convection due to flow of air through ventilation ports of cavities involving discrete heaters and/or solid obstacles (conductive or hot) at various locations within cavities.

Findings

Mixed convection plays an important role for various processes based on convection pattern and heat transfer rate. An important dimensionless number, Richardson number (Ri) identifies various convection regimes (forced, mixed and natural convection). Generalized models also depict the role of “aiding” and “opposing” flow and combination of both on mixed convection processes. Aiding flow (interaction of buoyancy and inertial forces in the same direction) may result in the augmentation of the heat transfer rate whereas opposing flow (interaction of buoyancy and inertial forces in the opposite directions) may result in decrease of the heat transfer rate. Works involving fluid media, porous media and nanofluids (with magnetohydrodynamics) have been highlighted. Various numerical and experimental works on mixed convection have been elucidated. Flow and thermal maps associated with the heat transfer rate for a few representative cases of unified models [Models 1–10] have been elucidated involving specific dimensionless numbers.

Originality/value

This review paper will provide guidelines for optimal design/operation involving mixed convection processing applications.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 9
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 18 May 2020

Yuan Ma, Mohammad Mehdi Rashidi, Rasul Mohebbi and Zhigang Yang

The nanofluid natural convection heat transfer in a hollow complex enclosure, which is named as Shamse knot shape, is studied numerically. This paper aims to present how…

Abstract

Purpose

The nanofluid natural convection heat transfer in a hollow complex enclosure, which is named as Shamse knot shape, is studied numerically. This paper aims to present how the Rayleigh number, nanoparticle volume fraction, Hartmann number and hollow side length affect the fluid flow and heat transfer characteristics.

Design/methodology/approach

The continuity, momentum and energy equations have been solved using lattice Boltzmann method (LBM). Numerical simulation has been obtained for a wide range of Rayleigh number (103 ≤ Ra ≤ 106), nanoparticle volume fraction (0 ≤ ϕ 0.05) and Hartmann number (0 ≤ Ha ≤ 60) to analyze the fluid flow pattern and heat transfer characteristics. Moreover, the effect of hollow side length (D) on flow field and thermal performance is studied.

Findings

The results showed that the magnetic field has a negative effect on the thermal performance and the average Nusselt number decreases by increasing the Hartmann number. Because of the high conduction heat transfer coefficient of nanoparticles, the average Nusselt number increases by rising the nanoparticle volume fraction. The effect of adding nanoparticles on heat transfer is more effective at low nanoparticle volume fraction (0 ≤ ϕ ≤ 0.01). It was also found that at Ra = 106, when the hollow side length increases to 3, the flow pattern becomes different due to the small gap. The averaged Nu is an increasing function of D at low Ra and an opposite trend occurs at high Rayleigh number.

Originality/value

For the first time, the effects of magnetic field, Rayleigh number, nanoparticle volume fraction and hollow side length on natural convection heat transfer of hybrid nanofluid (Ag-TiO2/water) is investigated in a complicated cavity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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