Numerical simulation of MHD double diffusive natural convection and entropy generation in a wavy enclosure filled with nanofluid with discrete heating

Abstract

A numerical investigation of entropy generation, heat and mass transfer is performed on steady double diffusive natural convection of water-based Al2O3 nanofluid within a wavy-walled cavity with a center heater under the influence of an uniform vertical magnetic field. The top horizontal wavy wall, left and right vertical walls of the enclosure are kept at low temperature and concentration of Tc and cc whereas central part of the bottom horizontal wall is maintained at high temperature and concentration of Th and ch and the remaining part is kept adiabatic where temperature and concentration gradient are taken as zero. The Bi-CGStab method and Tri-diagonal algorithm are used to solve the governing equations. The study has been performed for several relevant parameters such as Rayleigh number (103≤Ra≤105), Hartmann number (0≤Ha≤60), buoyancy ratio number (badbreakafter−2≤N≤2), volume fraction of nanoparticles (0.0≤ϕ≤0.2) and different undulation number of the upper wavy wall (n). The Prandtl number and Lewis number are kept fixed at Prgoodbreakafter=6.2 and Legoodbreakafter=2. The effect of these parameters are revealed in terms of streamlines, isotherms, isoconcentrations, entropy generation, average Nusselt number and Sherwood number. Results indicate that heat and mass transfer rate augment as Rayleigh number and volume fraction of nanoparticles increase and are found to drop with the increase in Hartmann number and buoyancy ratio.

Entropy generation in nanofluid flow due to double diffusive MHD mixed convection

“…where 1 , 2 and 3 are irreversibility distribution ratios and they are taken as 1 = 0.0001, 2 = 0.5 and 3 = 0.01 ( [22]).…”

“…According to the local thermodynamic equilibrium of linear transport theory, the dimensionless local entropy generation due to fluid friction, heat transfer, mass transfer and magnetic field in Cartesian coordinate are given by (see, [30] and [31] ) where , and are irreversibility distribution ratios and they are taken as and ( [22] ).…”

“…Various studies are performed on different geometries, such as: A numerical modelling of steady laminar mixed convection flow of water-Al 2 O 3 nanofluid in a lid-driven inclined square enclosure has been discussed by Abu-Nada and Chamkha [19] , Waheed [20] has studied heat transfer of mixed convection flow in rectangular enclosures with moving horizontal plate, mixed convection flow in a trapezoidal enclosure filled with two layers of nanofluid and porous media with a rotating circular cylinder and a sinusoidal bottom wall was studied by Hussein et al [21] , numerical investigation of double diffusive natural convection and entropy generation of nanofluid in a wavy enclosure with discrete heating in the presence of magnetic field have been discussed by Parveen and Mahapatra [22] , Chamkha et al [23] recently studied effects of a rotating cone on the mixed convection in a double lid-driven 3D porous trapezoidal cavity filled with nanofluid under the impact of magnetic field, mixed convection of hybrid nanofluid in a porous trapezoidal chamber was discussed by Cimpean et al [24] etc. In the analysis of entropy generation, the geometry of the cavity is also considerable as it varies for different shape of cavities.…”

Natural convection heat transfer in corrugated annuli with H2O-Al2O3 nanofluid

“…Therefore, it was extensively used in modern heat exchangers applicated in steam generation, condensation in power and cogeneration plants, chemical and agricultural products, automobile industry, etc. [44,45,46,47,48,49,50,51,52,53,54,55,56,57,58]. Hasanuzzamana et al 2007 [44], studied the natural convection in a square cavity having two V-wavy parallel vertical plates and two flat horizontal plates.…”

Free convection from a corrugated heated cylinder with nanofluids in a porous enclosure

“…Recently, Alhashash and Saleh 35 treated the porous media using Darcy model and found that the thermal performance were sensitive to the varying of corrugation property, Rayleigh number and nanoparticle volume fraction. Parveen and Mahapatra 36 studied double diffusive free convection in a wavy enclosure filled with nanofluid under partial heating. Free convection in a heat generating porous medium-filled wavy enclosures using Buongiorno’s nanofluid model was investigated by Ahmed and Rashed.…”