Effects of dissolved solute on unsteady double-diffusive mixed convective flow of a Buongiorno’s two-component nonhomogeneous nanofluid

Abstract

Purpose The purpose of this paper is to numerically study the unsteady double-diffusive mixed convective stagnation-point flow of a water-based nanofluid accompanied with one salt past a vertical flat plate. The effects of Brownian motion and thermophoresis parameters are also introduced through Buongiorno’s two-component nonhomogeneous equilibrium model in the governing equations. Design/methodology/approach In the present explanation of double-diffusive mixed convective model, there are four boundary layers entitled: velocity, thermal, solutal concentration and nanoparticle concentration. The resulting basic equations are solved numerically via an efficient Runge–Kutta fourth-order method with shooting technique after the governing nonlinear partial differential equations are converted into a system of nonlinear ordinary differential equations by the use of similarity transformations. Findings To avail the physical insight of problem, the effects of the mixed convection parameter, unsteadiness parameter and salt/nanoparticle parameters on the boundary layers behavior are investigated. Moreover, four possible types of diffusion problems entitled: double-diffusive nanofluid (DDNF), double-diffusive regular fluid (DDRF), mono-diffusive nanofluid (MDNF) and mono-diffusive regular fluid (MDRF) are considered to analyze and compare them in concepts of heat and mass transfer. Originality/value The results demonstrate that, for a regular fluid, without nanoparticle and salt (MDRF), the dimensionless heat transfer rate is smaller than other diffusion cases. As we include nanoparticle and salt (DDNF), the rate of heat transfer increases due to an increase in thermal conductivity and rate of diffusion of salt. Moreover, it is observed that the highest heat transfer rate is obtained for the situation that the thermophoretic effect of nanoparticles is negligible. Besides, the heat transfer rate enhances with the increase in the regular double-diffusive buoyancy parameter of salt.

Effect of viscous dissipation and induced magnetic field on an unsteady mixed convective stagnation point flow of a nonhomogenous nanofluid

“…2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 and 15 . The findings of the coefficient of local Nusselt number and skin friction are comparable with those of Ramachandran 52 , Lok et al 53 , and Kashani et al 54 for and various values of Pr , neglecting the parameters Scn , Nb , Nt , Nr , A , M , Ec , Vw , and . We noticed that the comparison shows a perfect agreement, and our approach gives identical results with the results obtained by others, so we concluded that the current results obtained are appropriate.…”

“… Pr Ramachandran et al 52 Lok et al 53 Kashani and Dinarvand 54 Present 0.7 1.706376 1.7063 1.7063 1.7063 7 1.517952 1.5179 1.5177 1.5179 40 1.410094 1.4101 1.4103 1.4101 …”

Influence of surface roughness on multidiffusive mixed convective nanofluid flow

“…Buongiorno has defined seven slip mechanisms to study the slip velocity of nanoparticles, among these, in the absence of turbulent flow, the Brownian diffusion and thermophoresis are the dominant one. Thus, to analyze the present problem, we adopt a Buongiorno two-phase model [29][30][31] and study the heat and mass transfer characteristics with the help of Brownian diffusion and thermophoresis slip mechanisms. Thus, the governing equations of the flow problem are given by [5,15]:…”

The impact of heterogeneous anisotropy of porous media on density-driven convection

“…On the other hand, numerical simulation is also widely employed to study the similar convection flow (Lewis and Schrefler, 1998; Lewis et al , 2004), e.g. heat and mass transfer in natural convection (El-Gendi and Aly, 2017; Nguyen et al , 2018; Shahsavar et al , 2019; Aliakbarzadeh et al , 2019), multiphase flow in oil reservoirs (Pao et al , 2001; Lewis and Pao, 2002; Pao and Lewis, 2002; Lewis et al , 2003; Masters et al , 2000) and double-diffusive convection (Peterson et al , 2010; Lewis and Sukirman, 1993). In addition, by solving Darcy’s equations, density-driven miscible flow in porous media had also been intensively simulated (Riaz et al , 2006; Ghesmat et al , 2011).…”