• M KHAN

      Articles written in Pramana – Journal of Physics

    • Aspects of improved heat conduction relation and chemical processes in 3D Carreau fluid flow

      M KHAN M IRFAN W A KHAN M AYAZ

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      This article communicates the numerical consideration of 3D Carreau liquid flow under the impact of chemical responses over a stretched surface. Moreover, the heat transfer exploration is carried out with a view to improve the heat flux relation. This phenomenon is established upon the theory of Cattaneo–Christov heat flux relation that contributes by the thermal relaxation. On exploitation of an appropriate transformation a system of nonlinear ODEs is attained and then elucidated numerically by means of bvp4c scheme. The descriptions of temperature and concentration fields equivalent to the frequent somatic parameters are graphically scrutinised.Our analysis carries that the concentration of the Carreau liquid displays similar tendency and decline as theheterogeneous–homogeneous reaction parameters ($k_{2}, k_{1}$) augment. Furthermore, it is notable that for shear thinning ($n$ & lt; 1) liquid, the influence of local Weissenberg numbers ($We_{1}, We_{2}$) are absolutely conflicting compared with the instance of shear thickening ($n$ & gt; 1) liquid. Additionally, validation of numerical results is done via benchmarking with previously stated limiting cases with two different schemes namely, homotopy analysis method (HAM) and bvp4c scheme. These comparisons initiate a superb correspondence with these outcomes.

    • Impact of autocatalysis chemical reaction on nonlinear radiative heat transfer of unsteady three-dimensional Eyring–Powell magneto-nanofluid flow

      W A KHAN A S ALSHOMRANI A K ALZAHRANI M KHAN M IRFAN

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      The pursuit of superior working liquids for heat/mass transfer mechanisms in engineering is on the rise, not only to maximise revenue but also to accommodate heat dissipation or chemical separation under extreme conditions. The addition of a small amount of nanoparticle, i.e. a product called nanofluid, has been initiated over the last decade. In this paper, we present a comprehensive study of unsteady three-dimensional (3D) flow of the Eyring–Powell nanofluid under convective and nanoparticles mass flux conditions. The effects of constructive/destructivechemical reactions and nonlinear thermal radiation are also considered in the Eyring–Powell nanofluid model. Additionally, suitable transformations are utilised to obtain coupled ordinary differential equations (ODEs) from the system of partial differential equations (PDEs) and the numerical solution of the system of the coupled ODEs is obtained by means of the bvp4c scheme. The obtained numerical data are plotted for the temperature and concentration profiles of nanofluids for various and converging values of physical parameters. Our findings demonstrate that the temperature of the Eyring–Powell nanofluid fall-off by changing the heat sink parameter. Furthermore, it is perceived from the sketches that the concentration of Eyring–Powell magneto-nanofluid decays at higher values of chemical reaction parameter.

    • Numerical interpretation of autocatalysis chemical reaction for nonlinear radiative 3D flow of cross magnetofluid

      W A KHAN M ALI F SULTAN M SHAHZAD M KHAN M IRFAN

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      A simple relation of chemical processes for three-dimensional flow of a cross magnetofluid over bidirectional stretched surface is constructed. The impact of convective heat transport in the manifestation of non-linear thermal radiation and features of heat source–sink are also considered for heat transfer mechanism.Furthermore, in this research paper, the innovative relation between heterogeneous and homogeneous responses with equivalent diffusivities for reactant and autocatalysis is exploited. Apposite alterations are guaranteed to obtain ordinary differential equations (ODEs) with high nonlinearity. Numerically, the bvp4c technique is exploited to the interpret the structure of ODEs. Portrayals of temperature and concentration for cross liquid equivalent to abundant somatic parameters are presented graphically as well as in tabular form. Our results reveal that the temperature of the cross fluid decreases with fluctuation in the heat sink parameter. Furthermore, it is perceived from the figuresthat the concentration of the cross fluid reduces for higher values of chemical reaction parameters.

    • Heat transfer enhancement for Maxwell nanofluid flow subject to convective heat transport

      M KHAN M IRFAN W A KHAN

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      Nanoliquids possess remarkable features that have fascinated numerous researchers because of their utilisation in nanoscience and nanotechnology. A mathematical relation for the two-dimensional flow of Maxwell nanoliquid over a stretching cylinder is established. Buongiorno’s relation is considered here to visualise the impact of Brownian moment and thermophoresis mechanisms on Maxwell liquid. The convective heat transport is deliberated for heat transfer mechanisms. Transformation procedure yields nonlinear differential system which is then computed through the homotopic approach. The results obtained are studied in detail in relation to somatic parameters. It is notable that the velocity of Maxwell liquid shows conflicting behaviour for curvature parameter $\alpha$ and Deborah number $\beta$. Moreover, the liquid temperature increases for increased values of Brownian motion $N_{b}$ and thermophoresis parameter $N_{t}$ . Additionally, the authentication of numerical consequences is prepared via benchmarking with formerly identified restrictive circumstances and we initiate a splendid communication with these results.

    • Theoretical aspects of thermophoresis and Brownian motion for three-dimensional flow of the cross fluid with activation energy

      F SULTAN W A KHAN M ALI M SHAHZAD M IRFAN M KHAN

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      The current review proclaims the forced convective flow and heat–mass transfer characteristics of cross nanofluid past a bidirectional stretched surface. The most significant aim of the current review is to incorporatethe features of Buongiorno relation, activation energy, nonlinear thermal radiation and heat sink–source for a three-dimensional flow of the cross fluid. Appropriate transformations are employed to transform the modelledpartial differential equations (PDEs) of momentum, temperature and concentration into coupled nonlinear ordinary differential equations (ODEs). The governing boundary value problem is numerically integrated with the help of bvp4c scheme. The obtained numerical data are plotted for the temperature and concentration profiles of nanofluid for various converging values of physical parameters. The dependence of increasing thermophysical parameters on temperature and concentration profiles of the cross nanofluid is graphically demonstrated. Furthermore, detailedstudy reveals that the concentration of the cross nanofluid decreases for increasing values of Brownian motion parameter. It is also perceived from the sketches that the concentration of the cross nanofluid decreases for higher values of chemical reaction parameter. The validity of the achieved numerical outcomes is ensured by making a comparison with the existing work as special cases.

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