Buoyancy-driven laminar free-convection flow, heat, and mass of a non-Newtonian nanofluid from a horizontal circular cylinder to a micropolar fluid have been investigated numerically using an implicit finite difference scheme. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. A nonsimilarity solution is presented that depends on the Prandtl number Pr, Schmidt number Sc, Brownian motion parameter Nb, thermophoresis parameter Nt, material parameter K, and buoyancy ratio parameter N. It is observed that increasing the Brownian motion parameter increases the temperature, Sherwood number, and wall couple stress but decreases the velocity, concentration, angular velocity, skin friction, and Nusselt number. An increase in the thermophoresis parameter is observed to accelerate the velocity, concentration, angular velocity, skin friction, and Nusselt number, whereas it decreases the temperature, the reduced Sherwood number, and wall couple stress. The velocity, angular velocity, Nusselt number, and wall couple stress are reduced with increasing material parameters, whereas the temperature, concentration, skin friction, and Sherwood number are enhanced. It is also observed that increasing material parameters increases velocity, angular velocity, skin friction, Nusselt number, and Sherwood number but decreases temperature, concentration, and wall couple stress. The model finds applications in energy systems and the thermal enhancement of industrial flow processes.

In this article, we investigate the nonlinear steady boundary layer flow and heat transfer of an incompressible Tangent Hyperbolic fluid from a sphere. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using implicit finite-difference Keller Box technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely Weissenberg number (We), power law index (n), Prandtl number (Pr), Biot number (cÞ and dimensionless tangential coordinate (nÞ on velocity and temperature evolution in the boundary layer regime is examined in detail. Furthermore, the effects of these parameters on heat transfer rate and skin friction are also investigated. Validation with earlier Newtonian studies is presented and excellent correlation is achieved. It is found that the velocity, Skin friction and the Nusselt number (heat transfer rate) are decreased with increasing Weissenberg number (We), whereas the temperature is increased. Increasing power law index (n) increases the velocity and the Nusselt number (heat transfer rate) but decreases the temperature and the Skin friction. An increase in the Biot number (cÞ is observed to increase velocity, temperature, local skin friction and Nusselt number. The study is relevant to chemical materials processing applications. ª 2015 Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). ª 2015 Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: S.A. Gaffar et al., Numerical study of flow and heat transfer of non-Newtonian Tangent Hyperbolic fluid from a sphere with Biot number effects, Alexandria Eng. J. (2015), http://dx.

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Numerous industrial processes such as continuous metal casting and polymer extrusion in metal spinning, include flow and heat transfer over a stretching surface. The theoretical investigation of magnetohydro-dynamic thermally radiative non-Darcy Nanofluid flows through a stretching surface is presented considering also the influences of thermal conductivity and Arrhenius activation energy. Buongiorno’s two-phase Nanofluid model is deployed in order to generate Thermophoresis and Brownian motion effects [1]. By similarity transformation technique, the transport equations and the respective boundary conditions are normalized and the relevant variable and concerned similarity solutions are presented to summarize the transpiration parameter. An appropriate Matlab software (Bvp4c) is used to obtain the numerical solutions. The graphical influence of various thermo physical parameters are inspected for momentum, energy and nanoparticle volume fraction distributions. Tables containing the Nusselt number, skin friction and Sherwood number are also presented and well argued. The present results are compared with the previous studies and are found to be well correlated and are in good agreement. The existing modelling approach in the presence of nanoparticles enhances the performance of thermal energy thermo-plastic devices.