Shape effect of nanoparticles on MHD nanofluid flow over a stretching sheet in the presence of heat source/sink with entropy generation

Abstract

Purpose In heat transfer, fluids and nanoparticles can provide new innovative technologies with potential to adapt the heat transfer fluid’s thermal properties through control over particle size, shape and others. This paper aims to examine the effects of spherical and non-spherical (cylinder, disk, platelets, etc.) shapes of silver (Ag) nanoparticles on heat transfer enhancement and inherent irreversibility in hydromagnetic water base nanoliquid flow over a convectively heated stretching sheet with heat generation/absorption. Design/methodology/approach Applying suitable similarity constraints, the model partial differential equations are transformed into a set of nonlinear ordinary differential equations. Solutions are obtained analytically via optimal homotopy asymptotic method (OHAM) and numerically via shooting technique coupled with the Runge-Kutta-Fehlberg (RK-F) method. Findings The impact of Ag nanoparticle’s shape along with other germane factors, such as Biot number, magnetic field, solid volume fraction and heat source/sink on velocity and thermal profiles, Nusselt number, skin friction coefficient, heat transfer enhancement, rate of entropy generation and irreversibility ratio, are scrutinized via graphical simulations and discussed. This study revealed that cylindrical shape Ag nanoparticles generate high entropy and fluid friction irreversibility, whereas disk shape Ag nanoparticles exhibit high transfer enhancement rate. Moreover, a boost in magnetic field intensity, volume-fraction parameter and Biot number enhances the thermal boundary layer thickness. Originality/value The main objective of this work is to examine the different Ag nanoparticles shape effects on the heat transfer enhancement and inherent irreversibility owing to hydromagnetic nanoliquid flow past a convectively heated stretching sheet with heat source/sink, which has not been yet studied. It is hope that this study will bridge the gap in the present literature and serve as impetus to scholars, engineers and industries for more exploration in this direction. The intrinsic nonlinearity of the model equations precludes its exact solution; hence, OHAM and shooting technique coupled with the RK-F method have been used to numerically tackle the problem. Pertinent results are discussed quantitatively and displayed graphically and in tabular form.

Heat transfer enhancement and entropy generation minimization using CNTs suspended nanofluid upon a convectively warmed moving wedge: An optimal case study

“…The enhancement on the Nusselt number is given as follows 35,36 : $$$En=\frac{N{u}_{\mathrm{nanofluid}}(\varphi )-N{u}_{\mathrm{base}\mathrm{fluid}}(\varphi =0)}{N{u}_{\mathrm{base}\mathrm{fluid}}(\varphi =0)}\times 100.$$$…”

“…Entropy production averaged number can be estimated using the following integral formula 33,36 : $$${[{N}_{{\rm{G}}}]}_{\mathrm{avg}}=\frac{1}{\forall }{\int }_{\forall }{N}_{{\rm{G}}}\unicode{x0200A}d\forall \,,$$$where $$\forall $$ is the boundary region's length regarding flow and temperature boundary layers.…”

“…The coupled nonlinear ODEs (11) and (12) with corresponding boundary settings (13) are computed methodically via optimal homotopy asymptotic method (OHAM) method 32,33,36 and numerically via the RKF method 33,36 …”

“…where γ th and γ fr denote the fraction of entropy generation due to thermal diffusion and viscous dissipation, respectively. Entropy production averaged number can be estimated using the following integral formula 33,36 :…”

MHD oscillatory flow of hybrid nanofluid along a vertical plate with ramped wall temperature, heat source, and thermal radiation: An exact solution

“…15 Heat production and nonuniform heat source simultaneous characteristics on time-dependent hybrid nanofluid flow over a moving vertical plate, considering the magnetic field, were studied by Vemula et al 16 Heat production and velocity slip effects on magnetized nanofluid flow across a straining sheet were presented by Misra and Kamatam. 17 Berrehal et al 18 examined the impact of heat source/sink and nanoparticles form on hydromagnetic nanofluid flow along an elongating surface with entropy production. Roy and Pop 19 addressed the sway of heat production and free convection on hybrid nanofluid flow via an oscillating vertical plate analytically.…”