Thermodynamic Analysis of Variable Viscosity MHD Unsteady Generalized Couette Flow with Permeable Walls

Abstract

The thermodynamic first and second law analyses of a temperature dependent viscosity hydromagnetic generalized unsteady Couette flow with permeable walls is investigated. The transient model problem for momentum and energy balance is tackled numerically using a semi-discretization method while the steady state boundary value problem is solved by shooting method together with Runge-Kutta-Fehlberg integration scheme. The velocity and the temperature profiles are obtained and are utilized to compute the skin friction coefficient, Nusselt number, entropy generation rate and the Bejan number. Pertinent results are presented graphically and discussed quantitatively.

Modelling the Effects of Variable Viscosity in Unsteady Flow of Nanofluids in a Pipe with Permeable Wall and Convective Cooling

“…where D B and D T are the Brownian and thermophoretic diffusion coefficients respectively, u is the nanofluid velocity in the z-direction, r is the radial distance, a is the pipe radius, T is the nanofluid temperature, P is the nanofluid pressure, t is the time, T a is the ambient temperature which also corresponds to the nanofluid initial temperature, ϕ is the concentration of nanoparticles, ρ f is the nanofluid density, α f is the thermal diffusivity of the nanofluid, and τ is the ratio of solid particles heat capacitance to that of the nanofluid heat capacitance. The dynamic viscosity of nanofluid is assumed to be temperature dependent which can be expressed as [7,22];…”

“…An analytic solution describing 2D steady laminar flow over an array of porous pipes for the case of low Reynolds number was presented by Moussy and Snider [3]. Several other researchers have done similar studies on heat transfer problems between two permeable parallel walls under different physical situations [4][5][6][7].…”

Thermodynamic analysis of a variable viscosity reactive hydromagnetic couette flow within parallel plates

“…To buttress the significant study on Couette flow, Makinde et al (2015) employed the first two laws of thermodynamics to examine the flow and thermal dissipation in MHD variable viscosity flow of a Couette flow in a spinning system. Other investigations on Couette flow and other physical properties are extensively presented in Makinde (2014), Theuri and Makinde (2014), and Vyas and Ranjan (2015).…”

Entropy Generation Rate in Unsteady Buoyancy-Driven Hydromagnetic Couple Stress Fluid Flow Through a Porous Channel

“…Adesanya and Falade [9] analysed the inherent irreversibility in the flow of hydrodynamic third grade fluid through a channel saturated with porous materials. Other important studies in this direction include [10,11,12,13,14,15,16,17,18,19] However, none of the references mentioned above on the analysis and entropy generation of non-Newtonian couple stress magnetohydromagnetic fluid flow has considered the analysis of entropy generation rate in magnetohydrodynamic couple stress fluid flow in porous channel. In reality, non-Newtonian couple stress fluid are used as working fluids in many technological and industrial processes, including polymer technology, petroleum industry [20].…”

“…In reality, non-Newtonian couple stress fluid are used as working fluids in many technological and industrial processes, including polymer technology, petroleum industry [20]. Motivated by studies in [6,7,8,9,21,10,11,12,13,14,15,16,17,18,19], the objective of the present study is to examine the influence of magnetic field and Ohmic heating of the couple stress fluid on the entropy production within the flow channel, which has not been accounted for in the literature. The outcoming results is expected to enhance many industrial and thermal engineering processes whose working medium is non-Newtonian fluid, with a view to minimise entropy generation which tends to deplete the amount of available energy for work.…”