Effects of temperature-dependent viscosity and thermal conductivity on mixed convection flow along a magnetized vertical surface

Abstract

Purpose-The purpose of this paper is to report a numerical solution for the problem of steady, two dimensional boundary layer buoyant flow on a vertical magnetized surface, when both the viscosity and thermal conductivity are assumed to be temperature-dependent. In this case, the motion is governed by a coupled set of three nonlinear partial differential equations, which are solved numerically by using the finite difference method (FDM) by introducing the primitive variable formulation. Calculations of the coupled equations are performed to investigate the effects of the different governing parameters on the profiles of velocity, temperature and the transverse component of magnetic field. The effects of the thermal conductivity variation parameter, viscosity variation parameter, magnetic Prandtl number Pm r , magnetic force parameter S, mixed convection parameter Ri and the Prandtl number Pr on the flow structure and heat transfer characteristics are also examined. Design/methodology/approach-FDM. Findings-It is noted that when the Prandtl number Pr is sufficiently large, i.e. Pr ¼ 100, the buoyancy force that driven the fluid motion is decreased that decrease the momentum boundary layer and there is no change in thermal boundary layer is noticed. It is also noted that due to slow motion of the fluid the magnetic current generates which increase the magnetic boundary layer thickness at the surface. It is observed that the momentum boundary layer thickness is increased, thermal and magnetic field boundary layers are decreased with the increase of thermal conductivity variation parameter ¼ 100. The maximum boundary layer thickness is increased for ¼ 100 and there is no change seen in the case of thermal boundary layer thickness but magnetic field boundary layer is deceased. The momentum boundary layer thickness shoot quickly for ¼ 40 but is very smooth for ¼ 50.There is no change is seen for the case of thermal boundary layer and very clear decay for ¼ 40 is noted. Originality/value-This work is original research work.

MHD natural convection in a square porous cavity filled with a water-based magnetic fluid in the presence of geothermal viscosity

“…Also, varying the fluids Prandtl number from 20 to 80, the rate of heat transfer increases by 93.35 per cent and faster cooling of the system occurs. Some interesting results on temperature-dependent viscosity can be found in Muhammad et al . (2016) and Sharma and Singh (2009).…”

Effects of temperature dependent viscosity and thermal conductivity on natural convection flow along a curved surface in the presence of exothermic catalytic chemical reaction

“…Umavathi et al [19] briefly described the combined effects of viscosity and variable thermal conductivity for steady natural convection flow both analytically and numerically by using perturbation and fourth order Runge-Kutta method. The effects of temperature dependent viscosity and thermal conductivity for free-forced convection flow has been keenly studied by Ashraf et al [20] along a magnetized vertical surface. Makanda [21] discussed the free convection flow around a spinning sphere by considering that viscosity, thermal conductivity and viscous dissipation are temperature dependent.…”

A comprehensive review on mixed convection for various patterns of kinematically and thermally induced scenarios within cavities

“…A number of earlier works in mixed convection involve studies in boundary layer (Mahdy and Chamkha, 2010; Tham et al , 2012; Patrulescu et al , 2014; Rosca et al , 2014; Muhammad et al , 2016) and stretching sheets/surface (Patil, 2012; Hayat et al , 2016; Patil et al , 2018a, 2018b, 2019). Till date, a number of studies were carried out on mixed convection within cavities and they are categorized into lid or wall(s) driven convection, flow due to the rotation of cylinders within a cavity and flow within vented or open cavities.…”