F.M. Abbasi

Influence of heat and mass flux conditions in hydromagnetic flow of Jeffrey nanofluid

This article explores the hydromagnetic steady flow of Jeffrey fluid in the presence of thermal radiation. The chosen nanofluid model takes into account the Brownian motion and thermophoresis effects. Flow and heat transfer characteristics are determined by a stretching surface with flux conditions. The nonlinear boundary layer flow through partial differential systems is converted into the ordinary differential systems. The resulting reduced systems are computed for the convergent solutions of velocity, temperature and nanoparticle concentration. Graphs of dimensionless temperature and nanoparticle concentration profiles are presented for different values of emerging parameters. Skin-friction coefficient are computed and analyzed in both hydrodynamic and hydromagnetic flow situations.

Analytical study of Cattaneo–Christov heat flux model for a boundary layer flow of Oldroyd-B fluid*

We investigate the Cattaneo–Christov heat flux model for a two-dimensional laminar boundary layer flow of an incompressible Oldroyd-B fluid over a linearly stretching sheet. Mathematical formulation of the boundary layer problems is given. The nonlinear partial differential equations are converted into the ordinary differential equations using similarity transformations. The dimensionless velocity and temperature profiles are obtained through optimal homotopy analysis method (OHAM). The influences of the physical parameters on the velocity and the temperature are pointed out. The results show that the temperature and the thermal boundary layer thickness are smaller in the Cattaneo–Christov heat flux model than those in the Fouriers law of heat conduction.

Hall and Ohmic Heating Effects on the Peristaltic Transport of a Carreau–Yasuda Fluid in an Asymmetric Channel

The effects of Hall current and Ohmic heating are analyzed for the peristaltic flow of a Carreau- Yasuda fluid in an asymmetric channel. The mathematical model for peristalsis of the Carreau- Yasuda fluid is provided for the first time in the literature. The problem is developed in the presence of viscous dissipation. Solutions for pressure gradient, stream function, axial velocity, and temperature are established and discussed. The heat transfer rate at the wall is first computed numerically and then examined. A comparative study for viscous, Carreau, and Carreau-Yasuda fluids is also made.

Peristaltic Motion of a non-Newtonian Nanofluid in an Asymmetric Channel

The peristaltic transport of a Carreau-Yasuda fluid in an asymmetric channel is studied. Problem formulation is given in the presence of nanoparticles and contributions of Brownian motion and thermophoresis are taken into account. Lubrication approach is employed. The resulting nonlinear system of equations is solved numerically, and the effects of sundry parameters on the velocity, temperature, and concentration are analyzed. Heat and mass transfer rates are computed and examined. The results show that the impact of the non-Newtonian parameters on flow quantities get reversed when we move from shear thinning to shear thickening fluids. The temperature of the nanofluid in presence of Brownian motion increases, furthermore the influence of Brownian motion parameter on temperature and concentration distributions is opposite

Impact of Magnetic Field on Mixed Convective Peristaltic Flow of Water Based Nanofluids with Joule Heating

Abstract Peristaltic transport of water-based nanofluids in the presence of applied magnetic field is studied. Two different types of nanofluids (silver-water and copper-water nanofluids) are used in the analysis. Effects of mixed convection, viscous dissipation, Joule heating, and heat generation/absorption are considered. Long wavelength and low Reynolds number approximations are used in the mathematical modelling. Numerical solutions are obtained for the velocity, pressure gradient, pressure rise per wavelength, temperature, and heat transfer rate at the wall. Physical quantities of interest are studied through graphs and tables. Comparison of water, silver-water, and copper-water nanofluid is presented. Results show that velocity and temperature of ordinary water are larger than those of nanofluids. Maximum velocity, temperature, and heat transfer rate at the wall of silver-water nanofluid is relatively higher than the copper-water nanofluid.

Mixed convection flow of jeffrey nanofluid with thermal radiation and double stratification

This article addresses the two-dimensional laminar boundary layer flow of magnetohydrodynamic (MHD) Jeffrey nanofluid with mixed convection. Effects of thermal radiation, thermophoresis, Brownian motion and double stratifications are taken into account. Rosseland’s approximation is utilized for the thermal radiation phenomenon. Convergent series solutions of velocity, temperature and nanoparticle concentration are developed. Graphs of dimensionless temperature and nanoparticle concentration are presented to investigate the influences of different emerging parameters. The values of skin-friction coefficient, local Nusselt and Sherwood numbers are computed and discussed for both Jeffrey and viscous fluids cases. We have observed that the temperature profile retarded for the larger values of Deborah number while an enhancement is noticed with the increasing values of ratio of relaxation to retardation times. Increasing values of thermal and nanoparticle concentration stratifications lead to a reduction in the temperature and nanoparticle concentration. The values of local Nusselt and Sherwood numbers are larger for the viscous fluid case when compared with Jeffrey fluid.

Mixed convective peristaltic flow of carbon nanotubes submerged in water using different thermal conductivity models

BACKGROUND AND OBJECTIVE Single Walled Carbon Nanotubes (SWCNTs) are the advanced product of nanotechnology having notable mechanical and physical properties. Peristalsis of SWCNTs suspended in water through an asymmetric channel is examined. Such mechanism is studied in the presence of viscous dissipation, velocity slip, mixed convection, temperature jump and heat generation/absorption. METHODS Mathematical modeling is carried out under the low Reynolds number and long wavelength approximation. Resulting nonlinear system is solved using the perturbation technique for small Brinkmans number. Physical analysis and comparison of the results in light of three different thermal conductivity models is also provided. CONCLUSIONS It is reported that the heat transfer rate at the boundary increases with an increase in the nanotubes volume fraction. The addition of nanotubes affects the pressure gradient during the peristaltic flow. Moreover, the maximum velocity of the fluid decreases due to addition of the nanotubes.

MHD peristaltic transport of spherical and cylindrical magneto-nanoparticles suspended in water

Advancements in the biomedical engineering have enhanced the usage of magnto-nanoparticles in improving the precision and efficiency of the magneto-drug delivery systems. Such systems make use of the externally applied magnetic fields to direct the drug towards a specific target in the human body. Peristalsis of magneto-nanofluids is of significant importance in such considerations. Hence peristaltic transport of Fe3O4-water nanofluid through a two-dimensional symmetric channel is analyzed in the presence of an externally applied constant magnetic field. Hamilton-Crosser’s model of the thermal conductivity is utilized in the problem development. The nanofluid saturates a non-uniform porous medium in which the porosity of the porous medium varies with the distance from the channel walls. Analysis is performed for the spherical and the cylindrical nanoparticles. Resulting system of equations is numerically solved. Impacts of sundry parameters on the axial velocity, temperature, pressure gradient and heat transfer rate at the boundary are examined. Comparison between the results for spherical and cylindrical nanoparticles is also presented. Results show that the nanoparticles volume fraction and the Hartman number have increasing effect on the pressure gradient throughout the peristaltic tract. Effective heat transfer rate at the boundary tends to enhance with an increase in the nanoparticles volume fraction. Use of spherical nanoparticles results in a higher value of axial velocity and the temperature at the center of channel when compared with the case of cylindrical nanoparticles.

Influence of Cattaneo-Christov heat flux in flow of an Oldroyd-B fluid with variable thermal conductivity

Purpose The purpose of this paper is to introduce the Cattaneo-Christov heat flux model for an Oldroyd-B fluid. Design/methodology/approach Cattaneo-Christov heat flux model is utilized for the heat transfer analysis instead of Fourier’s law of heat conduction. Analytical solutions of nonlinear problems are computed. Findings The authors found that the temperature is decreased with an increase in relaxation time of heat flux but temperature gradient is enhanced. Originality/value No such analysis exists in the literature yet.

Impact of Cattaneo-Christov heat flux on flow of two-types viscoelastic fluid in Darcy-Forchheimer porous medium

Purpose The aim of this works is to characterize the role of Cattaneo?Christov heat flux in two-dimensional flows of second-grade and Walter’s liquid B fluid models. Design/methodology/approach In this study similarity transformations have been used to transform the system into ordinary ones. Numerical and analytical solutions are computed through homotopic algorithm and shooting technique. Findings The numerical values of temperature gradient are tabulated, and the temperature gradient reduces rapidly with enhancing values of the Darcy parameter, but this reduction is very slow for Forchheimer parameter. Originality/value No such analyses have been reported in the literature.