Search results

1 – 10 of 19
To view the access options for this content please click here
Article
Publication date: 7 August 2018

Mohsen Sheikholeslami and Shirley Abelman

The purpose of this paper is to examine the effect of magnetic field on ferrofluid convective mode with radiation.

Abstract

Purpose

The purpose of this paper is to examine the effect of magnetic field on ferrofluid convective mode with radiation.

Design/methodology/approach

Viscosity of Fe3O4 ferrofluid is considered as a function of magnetic field. Solutions of the governing equations are obtained by a powerful numerical method, namely, control volume finite element method (CVFEM). Roles of radiation parameter (Rd), number of undulations (N), Fe3O4–water volume fraction (ϕ), Hartmann (Ha) and Rayleigh numbers are illustrated graphically. A correlation for Nuave is extracted.

Findings

The inner wall temperature decreases with increasing buoyancy forces, but increases with increasing Rd and Ha. Also increasing Rd results in increasing nanofluid motion. This influence is more evident when convection flow is dominant. As nanofluid temperature increases, the nanofluid begins moving from the warm surface to the outer one and dropping along the circular cylinder. At low Rayleigh number, conduction is more significant than convection. |Ψmax| increases as buoyancy force increases and it decreases as the Lorentz force increases. As Hartmann number increases, the center of the vortices moves to x = 0. As Ra increases, convection becomes stronger. Thus, |Ψmax| and temperature gradient increase with increasing Ra. As N increases, the distortion of isotherms reduces and vortices become weaker. Increasing Hartmann number results in a reduction in the thermal plume and the heat transfer mechanism changes from convection to conduction. Nusselt number decreases with increasing NNu decreases with increasing Lorentz force. At N = 5 , increasing the Lorentz force causes the main vortices to convert into three smaller ones. As the Lorentz force increases, the two upper vortices merge together and the thermal plume vanishes. The number of extrema in the Nuloc profile matches the existence of the thermal plume and the number of undulations. Nuave increases with increasing Rd. As buoyancy forces increase, the temperature decreases and in turn Nuave increases with increasing Ra.

Originality/value

Nanofluids are an innovative way to enhance radiation heat. In this paper, MHD Fe3O4–water nanofluid natural convection with radiation source term is examined. Magnetic field-dependent (MFD) viscosity is considered. Using the CVFEM, numerical simulations are carried out for various values of the radiation parameter (Rd = 0 to 0.8), volume fraction of Fe3O4–water (ϕ = 0 to 0.04), Rayleigh number (Ra = 103, 104 and 105), number of undulations (N = 3,4 and 5) and Hartmann number (Ha = 0 to 40).

Details

Engineering Computations, vol. 35 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 10 July 2018

Mohsen Sheikholeslami

The purpose of this paper is to simulate nanofluid laminar steady flow in a lid-driven porous cavity under the impact of Lorentz forces.

Abstract

Purpose

The purpose of this paper is to simulate nanofluid laminar steady flow in a lid-driven porous cavity under the impact of Lorentz forces.

Design/methodology/approach

Shape effect of nanoparticles and magnetic field impact on nanofluid properties are taken into consideration. The solutions of final equations are obtained by control volume based finite element method (CVFEM).

Findings

Graphs are depicted for different values of Darcy number, Fe3O4-water volume fraction, Reynolds and Hartmann numbers.

Originality/value

Results illustrated that using Platelet-shaped nanoparticles results in the highest Nusselt number. Nusselt number augments with rise of Darcy and Reynolds number.

Details

Engineering Computations, vol. 35 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 6 November 2017

M. Sheikholeslami

This main purpose of this paper is to investigate the influence of Lorentz forces on magnetic nanofluid free convection in a porous media. Control volume based finite…

Abstract

Purpose

This main purpose of this paper is to investigate the influence of Lorentz forces on magnetic nanofluid free convection in a porous media. Control volume based finite element method (CVFEM) is chosen to simulate the purpose of this paper. Influences of Darcy number, Fe3O4–water volume fraction, Hartmann and Rayleigh numbers on hydrothermal behavior are presented.

Design/methodology/approach

Magnetic nanofluid flow in a permeable medium is studied numerically using the non-Darcy model. Outputs are obtained by means of CVFEM.

Findings

Results indicated that isotherms become denser near the inner cylinder with augmentation of the permeability of the porous media. The Nusselt number enhances with an increase in buoyancy forces, Darcy number but it detracts with augment of Lorentz forces.

Originality/value

Results depict that the effect of the Hartmann number on rate of heat transfer is more observable in a medium with higher permeability.

Details

Engineering Computations, vol. 34 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 13 November 2018

M. Sheikholeslami, Hakan F. Öztop, Nidal Abu-Hamdeh and Zhixiong Li

The purpose of this paper is to research on CuO-water nanofluid Non-Darcy flow because of magnetic field. Porous cavity has circular heat source and filled with nanofluid…

Abstract

Purpose

The purpose of this paper is to research on CuO-water nanofluid Non-Darcy flow because of magnetic field. Porous cavity has circular heat source and filled with nanofluid. Lattice Boltzmann Method (LBM) has been used to simulate this problem.

Design/methodology/approach

In this research, LBM has been applied as mesoscopic approach to simulate water-based nanofluid free convection. Koo–Kleinstreuer–Li model is used to consider Brownian motion impact on nanofluid properties. Impacts of Rayleigh number, Darcy number, nanofluid volume fraction and Hartmann number on heat transfer treatment are illustrated.

Findings

It is found that temperature gradient decreases with rise of while it enhances with augment of Ha. Darcy number can enhance the convective flow.

Originality/value

The originality of this work is to analyze the to investigate magnetic field impact on water based CuO-H2O nanofluid natural convection inside a porous cavity with elliptic heat source.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 18 March 2021

Zahra Ebrahimpour, Mohsen Sheikholeslami, Seyyed Ali Farshad and Ahmad Shafee

This paper aims to model solar unit equipped with mirrors with numerical simulation. To augment the efficiency of system, absorber pipe was equipped with fins and…

Abstract

Purpose

This paper aims to model solar unit equipped with mirrors with numerical simulation. To augment the efficiency of system, absorber pipe was equipped with fins and nanomaterial was used as carrier fluid. Existence of secondary reflector results in better optical efficiency.

Design/methodology/approach

Finite volume approach is used for modeling which is done in two steps. The first one is done to achieve the heat flux distribution and second step to model turbulent flow inside the pipe. Verification has been presented for calculation of important functions (f and Nu). Outputs reveal the impacts of fin height (HF), number of fin (NF), inlet temperature (Tin) and velocity on irreversibility, thermal treatment.

Findings

Surface temperature decreases by 0.498, 0.07 and 0.017% with intensify of Re, HF and NF, respectively, when other factors were minimum. With augment of Tin, wall temperature increases about 9.87%. Given NF = 8, HF = 3 mmm, growth of Re makes Darcy factor to decrease about 28.28%, but it augments the Nu by 2.63%. Nu augments with rise of NF and HF about 2.63 and 7.66%. Irreversibility reduces about 29.5 and 11.65% with augment of NF and HF, respectively.

Originality/value

Numerical simulations for solar unit equipped with mirrors were reported in this modeling. To augment the efficiency of system, absorber pipe was equipped with fins and nanomaterial was used as carrier fluid. Existence of secondary reflector results in better optical efficiency. Finite volume approach is used for modeling which is done in two steps. The first one is done to achieve the heat flux distribution and second step to model turbulent flow inside the pipe. Verification has been presented for calculation of important functions (f and Nu). Outputs reveal the impacts of fin height (HF), number of fin (NF), inlet temperature (Tin) and velocity on irreversibility, thermal treatment.

Details

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

Keywords

To view the access options for this content please click here
Article
Publication date: 5 March 2018

M. Sheikholeslami and A. Zeeshan

This paper aims to investigate non-Darcy magnetohydrodynamic nanofluid flow in a uniformly porous medium. It is assumed that viscosity of nanofluid (Fe3O4-water) is a…

Abstract

Purpose

This paper aims to investigate non-Darcy magnetohydrodynamic nanofluid flow in a uniformly porous medium. It is assumed that viscosity of nanofluid (Fe3O4-water) is a function of external magnetic field. Roles of Darcy number, inclination angle, volume fraction of nanofluid, Hartmann and Rayleigh numbers are demonstrated graphically.

Design/methodology/approach

The problem is modeled, and simulation has been done by means of control volume base finite element method.

Findings

Results proved that Nusselt number enhances with augment of buoyancy forces and Darcy number while it decreases with the increase of Lorentz forces. Isotherms become denser near the inner cylinder with increase of inclination angle and the Darcy number.

Originality/value

As per the authors’ knowledge, this problem is new and not been published before.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Content available
Article
Publication date: 23 January 2019

M. Sheikholeslami, R. Ellahi, Ahmad Shafee and Zhixiong Li

The purpose of this paper is to present the entropy analysis of ferrofluid inside a porous space with magnetic force. Homogenous model with second law analysis is also…

Abstract

Purpose

The purpose of this paper is to present the entropy analysis of ferrofluid inside a porous space with magnetic force. Homogenous model with second law analysis is also taken into account.

Design/methodology/approach

Innovative model has been proposed and designed using control volume finite element method.

Findings

Experimental results demonstrate that Bejan number augments with augment of Rayleigh. As Hartmann number rises, exergy loss enhances. Exergy loss increases by increasing Hartmann number, whereas magnetic entropy generation reduces with the decrease of Ha. The proposed model can be used for combustion process and optimizing the performance of energy conversion system like gas turbine.

Originality/value

To the best of authors’ knowledge, this model is reported for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 9 April 2019

Mohsen Izadi, Nemat M. Maleki, Ioan Pop and S.A.M. Mehryan

This paper aims to numerically investigate the natural convection heat transfer of a hybrid nanofluid into a porous cavity exposed to a variable magnetic field.

Abstract

Purpose

This paper aims to numerically investigate the natural convection heat transfer of a hybrid nanofluid into a porous cavity exposed to a variable magnetic field.

Design/methodology/approach

The non-linear elliptical governing equations have been solved numerically using control volume based finite element method. The effects of different governing parameters including Rayleigh number (Ra = 103 − 106), Hartman number (Ha = 0 − 50), volume fraction of nanoparticles (φ = 0 − 0.02), curvature of horizontal isolated wall (a = 0.85 − 1.15), porosity coefficient (ε = 0.1 − 0.9) and Darcy number (Da = 10−5 − 10−1) have been studied.

Findings

The results indicate that at low Darcy numbers close to 0, the average Nusselt number Nua enhances as porosity coefficient increases. For a = 1 and a = 1.15 in comparison with a = 0.85, the stretching of the isothermal lines is maintained from the left side to the right side and vice versa, which indicates increased natural convection heat transfer for this configuration of the top and bottom walls. In addition, at higher Rayleigh numbers, by increasing the Hartmann number, a significant decrease is observed in the Nusselt number, which can be attributed to the decreased power of the flow.

Originality/value

The authors believe that all the results, both numerical and asymptotic, are original and have not been published elsewhere.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 3 January 2017

Umar Khan, Naveed Ahmed, Bandar Bin-Mohsen and Syed Tauseef Mohyud-Din

The purpose of this paper is to assess the flow of a nanofluid over a porous moving wedge. The passive control model along with the magnetohydrodynamic (MHD) effects is…

Abstract

Purpose

The purpose of this paper is to assess the flow of a nanofluid over a porous moving wedge. The passive control model along with the magnetohydrodynamic (MHD) effects is used to formulate the problem. Furthermore, in energy equation, the non-linear thermal radiation has also been incorporated. The equations governing the flow are transformed into a set of ordinary differential equations by using suitable similarity transforms. The reduced system of equations is then solved numerically using a well-known Runge–Kutta–Fehlberg method coupled with a shooting technique. The influence of parameters involved on velocity, temperature and concentration profiles is highlighted with the help of a graphical aid. Expressions for skin-friction coefficient, local Nusselt number and Sherwood number are obtained and presented graphically.

Design/methodology/approach

Numerical solution of the problem is obtained using the well-known Runge–Kutta–Fehlberg method.

Findings

The analysis provided gives a clear description that the increase in m and magnetic parameter M results in an increased velocity profile. Both these parameters normalize the velocity field. Radiation parameter, Rd, increases the temperature and concentration of the system so does the temperature ratio θω reduces the heat transfer rate at the wall for both stretching and shrinking wedge.

Originality/value

In the study presented, the flow of nanofluid over a moving permeable wedge is considered. The solution of the equations governing the flow is presented numerically. For the validity of results obtained, a comparison is also presented with already existing results. To the best of the authors’ knowledge, this investigation is the first of its kind on the said topic.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 12 July 2021

Waseem Asghar Khan

This study aims to introduce a modern higher efficiency predictor–corrector iterative algorithm.

Abstract

Purpose

This study aims to introduce a modern higher efficiency predictor–corrector iterative algorithm.

Design/methodology/approach

Furthermore, the efficiency of new algorithm is analyzed on the based on Chun-Hui He’s iteration method.

Findings

In comparison with the current robust algorithms, the newly establish algorithm behaves better and efficient, whereas the current existing algorithm fails or slows in the considered test examples.

Practical implications

The modified Chun-Hui He’s algorithm has great practical implication in numerous real-life challenges in different area of engineering, such as Industrial engineering, Civil engineering, Electrical engineering and Mechanical engineering.

Originality/value

The paper presents a modified Chun-Hui He’s algorithm for solving the nonlinear algebraic models exist in various area.

Details

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

Keywords

1 – 10 of 19