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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…

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

Keywords

Article
Publication date: 28 June 2019

Muhammad Ijaz Khan, Khursheed Muhammad, Tasawar Hayat, Shahid Farooq and Ahmed Alsaedi

This paper aims to discuss the salient aspects of the Darcy–Forchheimer flow of viscous liquid in carbon nanotubes (CNTs). CNTs are considered as nanofluid, and water is…

Abstract

Purpose

This paper aims to discuss the salient aspects of the Darcy–Forchheimer flow of viscous liquid in carbon nanotubes (CNTs). CNTs are considered as nanofluid, and water is taken as the continuous phase liquid. The flow features are discussed via curved surface. Water is taken as the base liquid. Flow is generated via nonlinear stretching. Energy expression is modeled subject to heat generation/absorption. Furthermore, convective conditions are considered at the boundary. The Xue model is used in the mathematical modeling which describes the features of nanomaterials. Both types of CNTs are considered, i.e. single-walled CNTs and multi-walled CNTs.

Design/methodology/approach

Appropriate transformations are used to convert the flow expressions into dimensionless differential equations. The bvp4c method is used for solution development.

Findings

Velocity enhances via higher estimations of nanoparticles volume fraction while decays for higher Forchheimer number, curvature parameter, behavior index and porosity parameter. Furthermore, thermal field is an increasing function of nanoparticle volume fraction, behavior index, Forchheimer number and porosity parameter.

Originality/value

Here, the authors have discussed two-dimensional CNTs-based nanomaterial Darcy–Forchheimer flow of viscous fluid over a curved surface. The authors believe that all the outcomes and numerical techniques are original and have not been published elsewhere.

Details

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

Keywords

Article
Publication date: 15 August 2019

Muhammad Ijaz Khan, Shahid Farooq, Tasawar Hayat, Faisal Shah and Ahmed Alsaedi

The novel mechanical, chemical and thermodynamics characteristics of both single- and multi-wall carbon nanotubes (CNTs) make them a subject of much attention for the…

Abstract

Purpose

The novel mechanical, chemical and thermodynamics characteristics of both single- and multi-wall carbon nanotubes (CNTs) make them a subject of much attention for the scientists and engineers from all domains. Fluid flows subject to CNTs are significant in biomedical engineering, energy storage systems, domestic and industrial cooling, automobile industries and solar energy collectors, etc. Keeping such effectiveness of CNTs in mind, this paper aims to examine peristaltic flow subject to CNTs in an asymmetric tapered channel. Both single and multiple walls CNTs are considered. The viscosity of nanomaterial depends on nanoparticles volume fraction and temperature. Total entropy rate through second law of thermodynamics is calculated. Heat source/sink and nonlinear heat flux are accounted.

Design/methodology/approach

The complicated flow expressions are simplified through lubrication approach. The velocity, temperature and entropy expressions are numerically solved by the built-in-shooting method.

Findings

The solutions for entropy generation, temperature and velocity are plotted, and the influences of pertinent variables are examined. The authors noticed that entropy generation is an increasing function of the Brinkman number.

Originality/value

The originality of this work is to communicate peristaltic CNTs-based nanomaterial peristaltic flow of viscous fluid in an asymmetric channel. 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

Keywords

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…

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

Keywords

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…

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

Article
Publication date: 31 July 2019

M.Z. Kiyani, Tasawar Hayat, I. Ahmad and Ahmed Alsaedi

The purpose of this study is to analyze the entropy generation in magnetohydrodynamics stagnation point mixed convection flow of Carreau nanofluid through porous medium.

Abstract

Purpose

The purpose of this study is to analyze the entropy generation in magnetohydrodynamics stagnation point mixed convection flow of Carreau nanofluid through porous medium.

Design/methodology/approach

The system is solved using the homotopy scheme.

Findings

Minimizing radiation, magnetic, permeability and temperature difference parameters responds to minimizing entropy production.

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

Article
Publication date: 10 December 2019

Muhammad Ijaz Khan, Sohail Ahmad Khan, Tasawar Hayat, Muhammad Waqas and Ahmed Alsaedi

The purpose of this paper is to investigate the entropy optimization in magnetohydrodynamic hybrid nanomaterials flows toward a stretchable surface. The energy expression…

Abstract

Purpose

The purpose of this paper is to investigate the entropy optimization in magnetohydrodynamic hybrid nanomaterials flows toward a stretchable surface. The energy expression is modeled subject to dissipation, heat generation/absorption and Joule heating. Here silicon dioxide (SiO2) and molybdenum disulfide (MoS2) as nanoparticles and propylene glycol (C3H8O2) as base fluid, respectively. Furthermore, the authors discussed the comparative study of molybdenum disulfide and silicon dioxide diluted in propylene glycol. The total entropy optimization rate is computed through implementation of the second law of thermodynamics.

Design/methodology/approach

The nonlinear partial differential system is reduced to an ordinary one through implementation of transformation. Newton built-in shooting method is used for computational results for the given system. Influences of various flow variables on the temperature, Bejan number, velocity, concentration and entropy generation rate are examined graphically for both nanoparticles (SiO2 and MoS2). Gradients of velocity and temperature are computed numerically for various physical parameters. Also, take the comparison between the present and previously published results in tabulated form.

Findings

For higher estimation of ϕ both temperature and velocity are enhanced. Entropy optimization and Bejan number have the opposite outcome for viscosity parameter. Temperature and velocity have opposite behaviors for larger values of magnetic parameter. Molybdenum disulfide (MoS2) is more efficient than silicon dioxide (SiO2).

Originality/value

No such work is yet published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 30 June 2021

Tasawar Hayat, Khursheed Muhammad and Ahmed Alsaedi

The purpose of this study is to analyze hybrid nanofluid (MWCNTs+Ag+Kerosene oil) over a stretched cylinder. Flow analysis is carried out in presence of stagnation-point…

Abstract

Purpose

The purpose of this study is to analyze hybrid nanofluid (MWCNTs+Ag+Kerosene oil) over a stretched cylinder. Flow analysis is carried out in presence of stagnation-point. Features of heat transport are examined via melting conditions.

Design/methodology/approach

Governed expression (partial differential equations) for flow and heat transfer are transmitted into ordinary differential equations (ODEs) via applying adequate transformations. For solutions development shooting method (bvp4c) is used on these non-linear coupled ODEs.

Findings

Comparative observation among hybrid nanofluid (MWCNTs+Ag+Kerosene oil), basefluid (kerosene oil) and nanofluid (MWCNTs+Kerosene oil) are performed. Influences of physical parameters on heat transfer rate, velocity, skinfriction coefficient and temperature are visualized graphically. Higher values nanoparticle volume fractions, curvature parameter, melting parameter and velocity ratio parameter lead to intensification in the velocity profile. The temperature of the fluid reduces with higher values nanoparticle volume fractions, curvature parameter and melting parameter. The surface friction coefficient is minimized via a higher melting parameter and velocity ratio parameter. Heat transmission rate intensifies with velocity ratio parameter, nanoparticle volume friction and curvature parameter while it reduces gradually with larger melting parameter. During comparative study performance of hybrid nanomaterial (MWCNTs+Ag+Kerosene oil) is outstanding and is proceeded by nanomaterial (MWCNTs+ Kerosene oil) and basefluid (kerosene oil).

Originality/value

In the presented study authors have analyzed the flow of hybrid nanomaterial (MWCNTs+Ag+Kerosene oil) by a stretching cylinder. The further cylinder is subjected to stagnation point and melting condition. The authors believe that all the consequences of the presented study and numerical technique (bvp4c) are original and not published before.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 June 2019

Muhammad Waqas, Saira Naz, Tasawar Hayat, Sabir Ali Shehzad and Ahmed Alsaedi

The purpose of this paper is to introduce the concept of improved Fourier–Fick laws subjected to variable fluid characteristics. Flow analysis in the stagnation region of…

Abstract

Purpose

The purpose of this paper is to introduce the concept of improved Fourier–Fick laws subjected to variable fluid characteristics. Flow analysis in the stagnation region of Oldroyd-B fluid is elaborated. Heat generation is present.

Design/methodology/approach

Optimal homotopy analysis method is used to obtain convergent solutions.

Findings

The outcomes reveal reduction in penetration depths of temperature and concentration due to involvement of thermal and solutal relaxation times of fluxes.

Originality/value

As per the authors’ knowledge, such analysis has not yet been reported.

Details

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

Keywords

Article
Publication date: 8 August 2019

Sadia Rashid, Tasawar Hayat, Sumaira Qayyum, Muhammad Ayub and Ahmed Alsaedi

The purpose of this paper is to examine outcome of activation energy in rotating flow of an Oldroyd-B nano liquid.

Abstract

Purpose

The purpose of this paper is to examine outcome of activation energy in rotating flow of an Oldroyd-B nano liquid.

Design/methodology/approach

Flow is generated due to stretched surface. Binary chemical reaction is studied. Brownian and thermophoresis effects are considered. The system of nonlinear ordinary differential equations is derived. Convergent series solutions are obtained by homotopy analysis method. The resulting expressions for velocities, temperature and concentration are computed for different embedded parameters.

Findings

It is found that velocities f′ and g  have decreasing effect when rotation parameter is enhanced. Brownian and thermophoresis are increasing functions of temperature and concentration. The physical quantities are sketched and discussed numerically. Concentration and temperature fields show decreasing behavior via Brownian and thermophoresis parameters.

Originality/value

Authors investigate the Rotating flow of Oldroyd-B nano fluid with chemical reactions. This work is not done yet in literature.

Details

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

Keywords

1 – 10 of 131