Zafar Hayat Khan
@nnnu.edu.cn
Professor, School of Mathematics & Statistics
Nanning Normal University
RESEARCH, TEACHING, or OTHER INTERESTS
Fluid Flow and Transfer Processes
Scopus Publications
Scopus Publications
Zafar Hayat Khan, K. Swain, S. Mohammed Ibrahim, Waqar A. Khan, and Zaitang Huang
Elsevier BV
Zafar Hayat Khan, Waqar A. Khan, Shaik Mohammed Ibrahim, K. Swain, and Zaitang Huang
Elsevier BV
Zafar Hayat Khan, W.A. Khan, S.M. Ibrahim, F. Mabood, and Zaitang Huang
Elsevier BV
Zafar Hayat Khan, Zhiquan Yang, Waqar A. Khan, Mikhail A. Sheremet, and Weifen Wu
Elsevier BV
O. D. Makinde, Zafar Hayat Khan, Alexander Trounev, Waqar A. Khan, and Rashid Ahmad
Wiley
AbstractThis paper presents a theoretical investigation of the inherent irreversibility in unsteady fractional time derivative mixed convection of a reacting nanofluid with heat and mass transfer mechanism over a slippery permeable plate embedded in a Darcy–Forchheimer porous medium. The model fractional partial differential equations are obtained based on conservation laws and numerically solved using the implicit finite difference scheme. The study displays and discusses the effects of various emerging parameters on the overall flow structure, such as velocity profiles, temperature distribution, nanoparticles concentration profiles, skin friction, Nusselt number, Sherwood number, entropy generation rate, and Bejan number. It was found that an increase in dimensionless time and fractional parameters leads to a decrease in both the entropy generation rate and the Bejan number. The study revealed that fractional order derivatives can capture intrinsic memory effects, non‐local behaviour, and anomalous diffusion in the nanofluid flow process. This can ultimately lead to better engineering system design and control.
Muhammad Usman, Oluwole Daniel Makinde, Zafar Hayat Khan, Rashid Ahmad, and Waqar Ahmed Khan
Elsevier BV
Krishan K. Verma, Xiu-Peng Song, Chhedi Lal Verma, Hai-Rong Huang, Munna Singh, Lin Xu, Jian-Ming Wu, Zafar Hayat Khan, Bao-Qing Zhang, and Yang-Rui Li
Elsevier BV
Zafar H Khan, Oluwole D Makinde, Muhammad Usman, Rashid Ahmad, Waqar A Khan, and Zaitang Huang
Oxford University Press (OUP)
Abstract This study focuses on fractional-order derivatives for the unsteady flow of magnetohydrodynamic (MHD) methanol-iron oxide (CH3OH-Fe3O4) nanofluid over a permeable vertical plate. The utilization of fractional-order derivatives provides a mathematical representation of the flow model. The concluding model, consisting of a system of fractional-order transient partial differential equations, has been solved using the finite difference method, and graphical illustrations demonstrate the effects of key parameters on the flow field. Velocity and temperature profiles provide insights into nanofluid behavior. Additionally, essential quantities such as skin friction coefficient, Nusselt number, Bejan number, and entropy generation rate have been depicted graphically. Comparison with previous studies authenticates the accuracy of the anticipated model, contributing to new intuitions into MHD nanofluid flow over a permeable vertical plate. It is worth noting that the current model, incorporating fractional-order derivatives, contributes to understanding the physical characteristics of MHD CH3OH-Fe3O4 nanofluid flow over a permeable vertical plate, research that has not been extensively explored before.
Muhammad Hamid, Zafar Hayat Khan, Waqar Ahmad Khan, and Zhenfu Tian
AIP Publishing
How to precisely study the natural convection inside the curvilinear geometries with electrically conductive fluids and multidirectional magnetic fields is a vital problem in fluid mechanics. Herein, a numerical study is performed to examine the naturally magnetoconvective flow enclosed in a right-angled shaped trapezoidal cavity. The multidirectional magnetic field is applied on the fluid flow inside the cavity. Triangular obstacles with different thermal boundary conditions are utilized in the cavity. The numerical simulation provides a detailed understanding of the fluid flow and heat transfer characteristics inside the trapezoidal cavity under the influence of multidirectional magnetic impacts. The numerical model can predict the flow patterns, temperature distribution, and heat transfer rates inside the cavity. It is demonstrated that the flow and heat transfer characteristics of a cavity can be significantly influenced by the presence of a magnetic field. Additionally, the presence of heated or cold obstacles inside the cavity can also have a substantial impact on these characteristics. The orientation of the magnetic field can also affect the temperature distribution and Nusselt number within the fluid flow. The results obtained from the numerical simulation can be used to optimize the design of the trapezoidal cavity for various industrial applications including electronic cooling, energy storage, heat exchangers, chemical processing, and solar collectors.
Zafar Hayat Khan, Noreen Sher Akbar, Javaria Akram, Muhammad Hamid, and Yangjiang Wei
Wiley
AbstractThe peristaltic flow of nanofluids is an emerging area of scientific research due to its vital industrial and medical applications. Herein, a model study is conducted to numerically investigate, the electroosmotically augmented peristaltic pumping of electrically conducting aqueous ionic nanofluid through an inclined asymmetric channel. The behavior of the model for various involved parameters is expressed through a set of graphs. The velocity profile gained a significant increment for Joule heating and electroosmotic velocity parameters. The velocity dropped for the Hartmann number, while a dual behavior is noted for the thermal Grashof number. However, the magnetic number enhances the temperature, while a lower temperature is perceived for the electroosmotic velocity and Debye length parameters. The streamline pattern for the fluid flow subject to multiple values of the electroosmotic velocity parameter can be seen to indicate that for negative values of the parameter, a larger number of streamlines are circulated compared to the case when the electric field is absent, that is, . However, in the case of an opposing electric field, that is, for the positive values of the parameter, the streamline bolus occurs across the centerline of the channel.
Zafar Hayat Khan, Waqar A. Khan, Zhiquan Yang, Muhamad Hamid, and Muhammad Qasim
Elsevier BV
Zheng Jun Song, Zafar Hayat Khan, Rashid Ahmad, Waqar Ahmad Khan, and Yangjiang Wei
Elsevier BV
Z. H. Khan, W. A. Khan, M. Qasim, S. O. Alharbi, M. Hamid, and M. Du
Springer Science and Business Media LLC
Zafar Hayat Khan, Muhammad Usman, Waqar Ahmed Khan, Muhammad Hamid, and Rizwan Ul Haq
Springer Science and Business Media LLC
Zafar Hayat Khan, Rashid Ahmad, Licheng Sun, and Waqar Ahmed Khan
Springer Science and Business Media LLC
Shafiq Ahmad, Zafar H Khan, Salman Zeb, and Muhammad Hamid
SAGE Publications
This article examined the effects of boundary layer flow and heat transport of a two-dimensional incompressible magnetohydrodynamic tangent hyperbolic fluid under slip boundary conditions and variable thermal conductivity. The entropy generation model is also analysed for the said fluid. Non-similarity transformations transformed the governing equations of the fluid and entropy generation model into dimensionless form. Maple software is used to solve the transformed equations numerically. Effects of different dimensionless parameters on entropy generation rate, Bejan number, velocity and temperature fields are studied thoroughly through graphs. It is observed that for higher values of velocity slip parameter and power-law index, the entropy generation rate decreases while the Bejan number increases. Also, for the Hartmann number, Weissenberg number and Brinkman number, we found an increase in the entropy generation rate, and reverse behaviour is observed for the Bejan number. Nusselt number, temperature profile and Bejan’s number increase with an increase in variable thermal conductivity.
Zafar H. Khan, Waqar A. Khan, Muhammad Qasim, and Min Du
Wiley
A computation analysis is performed to study double‐diffusive natural convection in a right‐angle trapezoidal cavity packed with a porous medium. The horizontal top and bottom boundaries are insulated and impermeable. The vertical left sidewall is kept at a constant heat flux and high concentration, whereas the inclined sidewall is held at lower temperature and concentration. The dimensionless nonlinear system is solved by employing the finite difference method along the successive Under Relaxation technique. The findings are compared and validated with the existing literature for the Darcy flow driven through a single buoyancy effect (difference in density is only due to temperature variations) in a porous square enclosure. The numerical results are expressed in the form of streamlines, isotherms and iso‐concentrations, and local and average Nusselt and Sherwood numbers. It is observed that the buoyancy parameter reduces the dimensionless temperature of the cavity and increases the dimensionless concentration due to the strong impact of buoyancy. Smaller values of the Lewis number enhance heat transfer, whereas higher values reduce it. Moreover, the Rayleigh number and buoyancy parameter enhance both surface heat and concentration rates.
Salman Ahmad and Z. H. Khan
World Scientific Pub Co Pte Ltd
In this paper, we focused on time-dependent flow of micropolar fluid between parallel permeable plates. Fluid is electrically conducting. Magnetic field is applied in the transverse direction to flow. Energy equation is modeled in the presence of viscous dissipation, thermal radiation and Joule heating. Suction is considered at lower plate while injection is considered at upper plate. Appropriate dimensionless variables are employed to reduce the governing PDE’s system into dimensionless one. Nondimensional PDE system is tackled numerically by finite difference technique. Effects of flow parameters on velocity, micro-rotation, temperature, couple and shear stresses at plates and Nusselt number are discussed. The obtained outputs show that for nonzero electric field parameter the velocity increases with Hartmann number. For zero electric field parameter the velocity decreases with Hartmann number. Temperature increases with both electric and magnetic field parameters. Micro-rotation decreases with micro-rotation material parameter and it increases with time.
Zafar H. Khan, Waqar A. Khan, Ahmed M. R. Elbaz, Muhammad Qasim, Sayer O. Alharbi, and Licheng Sun
Wiley
AbstractComputational analysis of convective heat transfer characteristics of Al2O3–Cu‐water hybrid nanofluid inside a triangular fin‐shaped cavity is performed. A heater of different lengths is attached to the base wall while the other walls are kept cold. The governing equations are modeled and transformed into dimensionless forms by utilizing dimensionless variables. For further investigation of the problem obtained, dimensionless coupled partial differential equations with appropriate boundary conditions are solved numerically using Galerkin Finite element method. A grid dependency test is carried out to check the efficiency and accuracy of the proposed numerical method. Impact of heater length, nanoparticle volume fraction and Rayleigh number on the dimensionless velocity, temperature, streamlines, isotherms, local and average Nusselt number is investigated through graphical analysis. It is demonstrated that the local and average Nusselt numbers increase with Rayleigh number and solid volume fraction of both nanoparticles. It is important to note that the results of this investigation are useful for cooling systems in various thermal devices, building structures, and electronic components.
Zafar H. Khan, Waqar A. Khan, Mikhail A. Sheremet, Jiguo Tang, and Licheng Sun
Elsevier BV
Shankar Goud Bejawada, Zafar Hayat Khan, and Muhammad Hamid
Wiley
AbstractA model study is reported to examine the effect of magnetic hydrodynamics polar fluid over a semistretched infinite vertical porous surface in the presence of heat source, temperature, magnetic field, and thermal radiation. The governing dimensional partial differential equations are transformed into an ordinary differential equation set by introducing the similarity variables. The reduced model is numerically solved via Runge–Kutta fourth order along with the shooting technique. The effects of various physical parameters on coefficient of skin friction, microrotation coefficient, and Nusselt number are studied whereas the outcomes are explained through a set of graphs. The results obtained are explained in tabular form and graphs. Prandtl and Hartman's numbers enhance the velocity profile while the opposite behavior is noticed for . Higher values of Pr enlarge the angular velocity near the surface. Improved temperature distribution is noticed for higher values of Ha and ϕ, However, a declined behaviour is observed for , and .
Zafar Hayat Khan, Waqar Ahmad Khan, M. A. Sheremet, Muhammad Hamid, and Min Du
AIP Publishing
Analysis on natural convective heat transfer in different engineering systems allows optimization of the technical apparatus. For this purpose, numerical simulation of the fluid flow and heat transport within the system is combined with study of entropy generation. The latter is very important considering the Gouy–Stodola theorem of thermodynamics. The present research deals with the mathematical modeling of thermal convection and entropy generation in a right-angled trapezoidal cavity under the influence of sinusoidal vertical wall temperature distribution. Control Oberbeck–Galerkin finite element technique has solved Boussinesq equations formulated using the non-dimensional primitive variables. Analyses of flow structures, thermal and entropy generation patterns for different values of the Rayleigh number, and parameters of non-uniform wall temperature were performed. It was found that a rise in the sinusoidal wall temperature amplitude increases the average Nusselt and Bejan numbers and average entropy generation. Moreover, growth in the non-uniform wall temperature wave number decreases the energy transport strength and Bejan number.
Z.H. Khan, Muhammad Hamid, W.A. Khan, L. Sun, and H. Liu
Elsevier BV
Muhammad Usman, Tamour Zubair, Muhammad Hamid, Rizwan Ul Haq, and Zafar Hayat Khan
Wiley
AbstractThe objective of the current article is to explore the unsteady flow and heat transfer of magnetohydrodynamics tangent‐hyperbolic fluid flow over a stretching sheet. The governing flow model is transformed into a nonlinear set of ordinary differential equations by utilizing the appropriate similarity techniques. A new modification is introduced into the traditional Legendre wavelet method to obtain the results of the model mentioned above. The classic wavelet scheme is unable to find the solution for an infinite domain. Hence, we successfully extended it for an infinite domain and used it to attain the significant findings of the fluid problem. Additionally, the study of emerging parameters on temperature and velocity profiles is reported graphically. The velocity behavior is decreasing for the physical parameters, namely, power‐lax index, unsteadiness, Hartmann number, and Weissenberg number. The temperature profile is an increasing function for power‐law index and Eckert number while the behavior is the opposite for the Prandtl number. Moreover, a tabular form comparison of outcomes with existing literature, convergence, and error analysis is provided in our study, which confirms the credibility of the suggested method. The obtained results endorse the credibility and reliability of the proposed method; therefore, it could be extended for other nonlinear problems of complex nature.
Muhammad Usman, Muhammad Hamid, Zafar Hayat Khan, and Rizwan Ul Haq
Elsevier BV