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Article
Publication date: 26 September 2019

Muhammad Ijaz Khan, Sohail Ahmad Khan, Tasawar Hayat, Muhammad Faisal Javed and Muhammad Waqas

This paper aims to address the flow features of Ree–Eyring fluid between two rotating disks subject to the magnetic field. Heat transfer features are discussed through viscous…

58

Abstract

Purpose

This paper aims to address the flow features of Ree–Eyring fluid between two rotating disks subject to the magnetic field. Heat transfer features are discussed through viscous dissipation and nonlinear thermal radiation. Impact of thermophoresis and Brownian movement are elaborated. Physical characteristics of entropy generation optimization in nanofluid with homogeneous and heterogeneous chemical reaction are discussed.

Design/methodology/approach

The nonlinear system leads to ordinary one through the implementation of adequate transformation and then tackled analytically for a convergent series solution by homotopy analysis method.

Findings

The prime objective of the present research has been given to investigate entropy generation in Ree–Eyring fluid flow between two rotating disks subjected to the magnetic field. Vital features, namely, Brownian motion and thermophoresis have been addressed. Total entropy rate is computed using the second law of thermodynamics.

Originality/value

No such work yet exists in the literature.

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Article
Publication date: 3 May 2019

Muhammad Ijaz Khan, Sohail Ahmad Khan, Tasawar Hayat, Muhammad Faisal Javed and Ahmed Alsaedi

This study aims to examine the flow characteristics of Ree–Eyring fluid between two rotating disks. The characteristics of heat transfer are discussed in presence of viscous…

77

Abstract

Purpose

This study aims to examine the flow characteristics of Ree–Eyring fluid between two rotating disks. The characteristics of heat transfer are discussed in presence of viscous dissipation, heat source/sink and nonlinear radiative heat flux.

Design/methodology/approach

Nonlinear flow expressions lead to ordinary ones through adequate similarity transformations. The ordinary differential system has been tackled through optimal homotopic method. The impact of different flow variables on the velocity field, entropy generation rate and temperature fields is graphically discussed. The surface drag force and heat transfer rate are numerically examined via various pertinent parameters.

Findings

By minimization of values of stretching parameter and Brinkman number, the entropy generation rate can be controlled. The entropy generation rate enhances for higher values of magnetic parameter, while the Bejan number is decreased via magnetic parameter.

Originality/value

No such work is yet published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 24 September 2019

Himanshu Upreti and Manoj Kumar

The purpose of this paper is to examine the effect of non-linear thermal radiation, Joule heating and viscous dissipation on the mixed convection boundary layer flow of MHD…

103

Abstract

Purpose

The purpose of this paper is to examine the effect of non-linear thermal radiation, Joule heating and viscous dissipation on the mixed convection boundary layer flow of MHD nanofluid flow over a thin moving needle.

Design/methodology/approach

The equations directing the flow are reduced into ODEs by implementing similarity transformation. The Runge–Kutta–Fehlberg method with a shooting technique was implemented.

Findings

Numerical outcomes for the coefficient of skin friction and the rate of heat transfer are tabulated and discussed. Also, the boundary layer thicknesses for flow and temperature fields are addressed with the aid of graphs.

Originality/value

Till now, no numerical study investigated the combined influence of Joule heating, non-linear thermal radiation and viscous dissipation on the mixed convective MHD flow of silver-water nanofluid flow past a thin moving needle. The numerical results for existing work are new and their novelty verified by comparing them with the work published earlier.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 18 November 2019

Muhammad Ijaz Khan, Salman Ahmad, Tasawar Hayat, M. Waleed Ahmad Khan and Ahmed Alsaedi

The purpose of this paper is to address entropy generation in flow of thixotropic nonlinear radiative nanoliquid over a variable stretching surface with impacts of inclined…

116

Abstract

Purpose

The purpose of this paper is to address entropy generation in flow of thixotropic nonlinear radiative nanoliquid over a variable stretching surface with impacts of inclined magnetic field, Joule heating, viscous dissipation, heat source/sink and chemical reaction. Characteristics of nanofluid are described by Brownian motion and thermophoresis effect. At surface of the sheet zero mass flux and convective boundary condition are considered.

Design/methodology/approach

Considered flow problem is mathematically modeled and the governing system of partial differential equations is transformed into ordinary ones by using suitable transformation. The transformed ordinary differential equations system is figure out by homotopy algorithm. Outcomes of pertinent flow variables on entropy generation, skin friction, concentration, temperature, velocity, Bejan, Sherwood and Nusselts numbers are examined in graphs. Major outcomes are concluded in final section.

Findings

Velocity profile increased versus higher estimation of material and wall thickness parameter while it decays through larger Hartmann number. Furthermore, skin friction coefficient upsurges subject to higher values of Hartmann number and magnitude of skin friction coefficient decays via materials parameters. Thermal field is an increasing function of Hartmann number, radiation parameter, thermophoresis parameter and Eckert number.

Originality/value

The authors have discussed entropy generation in flow of thixotropic nanofluid over a variable thicked surface. No such consideration is yet published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 24 August 2021

Muhammad Faisal Javed, Mohammed Jameel, Muhammad Ijaz Khan, Sumaira Qayyum, Niaz B. Khan and Tufail Ahmad Khan

This study aims to focus on second grade fluid flow over a rotating disk in the presence of chemical reaction. Uniform magnetic field is also taken into account. Because of the…

100

Abstract

Purpose

This study aims to focus on second grade fluid flow over a rotating disk in the presence of chemical reaction. Uniform magnetic field is also taken into account. Because of the smaller magnetic Reynolds number, induced magnetic field is negligible. Heat equation is constructed by considering heat source/sink.

Design/methodology/approach

Suitable variables are used to transform nonlinear partial differential equations to ordinary ones. Convergent series solutions are attained by applying homotopy analysis method.

Findings

Trends of different parameters on concentration, velocity and temperature are shown graphically. Skin friction coefficient and local Nusselt number are calculated and investigated under the effect of elaborated parameters. An elevation in the value of magnetic field parameter causes collapse in the velocity distributions. Velocity distribution in increasing function of viscoelastic parameter. Temperature and concentration profiles are decreasing functions of viscoelastic parameter. Concentration distribution reduces by increasing the chemical reaction parameter. There is more surface drag force for larger M, while opposite behavior is noted for β.

Originality/value

To the best of the authors’ knowledge, such consideration is yet to be published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 11
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 25 June 2019

Sohail Ahmad Khan, Muhammad Ijaz Khan, Tasawar Hayat, Muhammad Faisal Javed and Ahmed Alsaedi

The purpose of this paper is to address the impact of induced magnetic field in mixed convective stagnation flow of TiO2-Cu-water hybrid nanofluid towards a stretchable sheet…

168

Abstract

Purpose

The purpose of this paper is to address the impact of induced magnetic field in mixed convective stagnation flow of TiO2-Cu-water hybrid nanofluid towards a stretchable sheet. Non-linear thermal radiation and heat source/sink are accounted. Flow of hybrid nanofluid is discussed. Non-linear partial differential expressions are converted to ordinary ones through appropriate transformations.

Design/methodology/approach

The obtained systems are solved for convergence solutions via homotopy analysis method. Graphical results are discussed for different physical variables on the velocity, induced magnetic field and temperature fields for both Cu water nanofluid and TiO2-Cu-water hybrid nanofluid. Finally, the effect of different physical variables on skin friction coefficient (Cfx) and Nusselt number Nux in the presence of water nanofluid and TiO2-Cu-water hybrid nanofluid are discussed.

Findings

Velocities and induced magnetic field are increasing functions of mixed convection parameter and nanoparticle volume fraction. Temperature rises for higher radiation parameter. Skin friction is greater in case of Cu-water nanoliquid, while Nusselt number is less for Cu-water nanofluid when they are compared with hybrid nanoliquid TiO2-Cu-water.

Originality/value

No such work is not yet present in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 31 July 2019

Waqar Azeem Khan, Mehboob Ali, Muhammad Waqas, M. Shahzad, F. Sultan and M. Irfan

This paper aims to address the flow of Sisko nanofluid by an unsteady curved surface. Non-uniform heat source/sink is considered for heat transfer analysis.

123

Abstract

Purpose

This paper aims to address the flow of Sisko nanofluid by an unsteady curved surface. Non-uniform heat source/sink is considered for heat transfer analysis.

Design/methodology/approach

Numerical solutions are constructed using bvp4c procedure.

Findings

Pressure profile inside boundary region is increased when A and K are enhanced.

Originality/value

No such analysis is yet presented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 12
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 22 July 2019

Muhammad Ijaz Khan, Sumaira Qayyum, Tasawar Hayat and Ahmed Alsaedi

The purpose of this paper is to analyze the Sutterby fluid flow by a rotating disk with homogeneous-heterogeneous reactions. Inspection of heat transfer is through…

95

Abstract

Purpose

The purpose of this paper is to analyze the Sutterby fluid flow by a rotating disk with homogeneous-heterogeneous reactions. Inspection of heat transfer is through Cattaneo–Christov model. Stratification effect is also considered.

Design/methodology/approach

Nonlinear equations are solved by the homotopy technique.

Findings

Sutterby fluid flow by rotating disk is not considered yet. Here the authors intend to analyze it with Cattaneo–Christov heat flux and homogeneous-heterogeneous reactions. Thermal stratification is also taken into consideration.

Originality/value

No such work is yet done in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 12 August 2021

Wasiq Ullah, Faisal Khan, Muhammad Umair and Bakhtiar Khan

This paper aims to reviewed analytical methodologies, i.e. lumped parameter magnetic equivalent circuit (LPMEC), magnetic co-energy (MCE), Laplace equations (LE), Maxwell stress…

91

Abstract

Purpose

This paper aims to reviewed analytical methodologies, i.e. lumped parameter magnetic equivalent circuit (LPMEC), magnetic co-energy (MCE), Laplace equations (LE), Maxwell stress tensor (MST) method and sub-domain modelling for design of segmented PM(SPM) consequent pole flux switching machine (SPMCPFSM). Electric machines, especially flux switching machines (FSMs), are accurately modeled using numerical-based finite element analysis (FEA) tools; however, despite of expensive hardware setup, repeated iterative process, complex stator design and permanent magnet (PM) non-linear behavior increases computational time and complexity.

Design/methodology/approach

This paper reviews various alternate analytical methodologies for electromagnetic performance calculation. In above-mentioned analytical methodologies, no-load phase flux linkage is performed using LPMEC, magnetic co-energy for cogging torque, LE for magnetic flux density (MFD) components, i.e. radial and tangential and MST for instantaneous torque. Sub-domain model solves electromagnetic performance, i.e. MFD and torque behaviour.

Findings

The reviewed analytical methodologies are validated with globally accepted FEA using JMAG Commercial FEA Package v. 18.1 which shows good agreement with accuracy. In comparison of analytical methodologies, analysis reveals that sub-domain model not only get rid of multiples techniques for validation purpose but also provide better results by accounting influence of all machine parts which helps to reduce computational complexity, computational time and drive storage with overall accuracy of ∼99%. Furthermore, authors are confident to recommend sub-domain model for initial design stage of SPMCPFSM when higher accuracy and low computational cost are primal requirements.

Practical implications

The model is developed for high-speed brushless AC applications.

Originality/value

The SPMCPFSM enhances electromagnetic performance owing to segmented PMs configuration which makes it different than conventional designs. Moreover, developed analytical methodologies for SPMCPFSM reduce computational time compared with that of FEA.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 22 July 2019

Waqar Azeem Khan, Muhammad Waqas, Mehboob Ali, F. Sultan, M. Shahzad and M. Irfan

This paper aims to develop a mathematical model featuring Brownian motion and thermophoresis. The idea of curved stretching subjected to time-dependent non-Newtonian (Sisko) fluid…

87

Abstract

Purpose

This paper aims to develop a mathematical model featuring Brownian motion and thermophoresis. The idea of curved stretching subjected to time-dependent non-Newtonian (Sisko) fluid flow is introduced.

Design/methodology/approach

Shooting scheme is implemented to compute nonlinear systems.

Findings

Velocity profile of Sisko magnetonanofluid enhances for augmented values of curvature parameter.

Originality/value

To the best of the authors’ knowledge, no such analysis has yet been reported.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

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