Numerical Simulations of Magnetohydrodynamics Natural Convection and Entropy Production in a Porous Annulus Bounded by Wavy Cylinder and Koch Snowflake Loaded with Cu–Water Nanofluid

Abstract

The current paper presents a numerical study of the magnetohydrodynamics natural convection and entropy production of Cu–water nanofluid contained in a porous annulus between a heated Koch snowflake and wavy cylinder with lower temperature with respect to the Koch snowflake. The numerical algorithm is based on the Galerkin Finite Element Method. The impacts of Rayleigh number (Ra = 103, 104, 105, and 106), Hartman number (Ha = 0, 25, 50, and 100), Darcy number (Da = 10−2, 10−3, 10−4, and 10−5), nanoparticle volumetric fraction (φ = 2%, 3%, 4%, and 5%), and the undulations number of the outer wavy cylinder (three cases) on the distributions of isotherms, streamlines, mean Nusselt number (Nuavg), as well as on total entropy production and Bejan number are thoroughly examined. The computational outcomes disclose that dispersing more Cu nanoparticles in the base fluid and creating a flow with higher intensity inside the annulus by raising the Rayleigh number bring about a boosted natural convective flow in the cavity, which improves the heat transmission rate. In addition, it can be noted that owing to the peculiar form of the heated Koch snowflake, nanofluid gets trapped between the angled parts, resulting in uneven temperature profiles with higher values in these places.

Numerical Study of Lid-Driven Hybrid Nanofluid Flow in a Corrugated Porous Cavity in the Presence of Magnetic Field

“…Equations (1)–(5) are numerically treated utilizing the Galerkin weighted residual finite element approach [ 46 , 47 , 48 ]. This approach simplifies the solution of nonlinear partial differential equations by converting them to a set of integral equations.…”

The baffle shape effects on natural convection heat transfer in nanofluid-filled permeable container with magnetic field

“…The governing equations for mass, momentum, and energy of the situation under investigation may be defined using the following dimensional form based on the presumptions indicated above [10]:…”

“…Finally, GFEM was invented to solve the abovementioned fundamental equations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) and suitable boundary conditions (20)(21)(22). The Galerkin weighted residual approach was utilized to transform these fundamental equations into integral equations.…”

“…Thus, to ameliorate the thermal processes of such devices, different strategies are of great necessity to be investigated, namely, the application of magnetic fields. In this respect, numerous investigations were reported in the literature to identify this subject [7][8][9][10]. Cao et al [11] examined the natural convection of nanoliquid within a square heat exchanger chamber supplied with two cylinders that functioned as heaters and coolers on both sides in the application of magnetic intensity.…”

MHD Hybrid Nanofluid Mixed Convection Heat Transfer and Entropy Generation in a 3-D Triangular Porous Cavity with Zigzag Wall and Rotating Cylinder

“…Nevertheless, the magnitude of the increment in heat transmission stated in the literature varies greatly. Numerous research articles (both experimental and computational) on application of nanofluids in various fields have been published [4][5][6][7][8].…”