Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

Abstract

This numerical study considers the mixed convection and the inherent entropy generated in Al 2 O 3 –water nanofluid filling a cavity containing a rotating conductive cylinder. The vertical walls of the cavity are wavy and are cooled isothermally. The horizontal walls are thermally insulated, except for a heat source segment located at the bottom wall. The dimensionless governing equations subject to the selected boundary conditions are solved numerically using the Galerkin finite-element method. The study is accomplished by inspecting different ranges of the physical and geometrical parameters, namely, the Rayleigh number ( 10 3 ≤ R a ≤ 10 6 ), angular rotational velocity ( 0 ≤ Ω ≤ 750 ), number of undulations ( 0 ≤ N ≤ 4 ), volume fraction of Al 2 O 3 nanoparticles ( 0 ≤ ϕ ≤ 0.04 ), and the length of the heat source ( 0.2 ≤ H ≤ 0.8 ) . The results show that the rotation of the cylinder boosts the rate of heat exchange when the Rayleigh number is less than 5 × 10 5 . The number of undulations affects the average Nusselt number for a still cylinder. The rate of heat exchange increases with the volume fraction of the Al 2 O 3 nanoparticles and the length of the heater segment.

Role of Rotating Cylinder toward Mixed Convection inside a Wavy Heated Cavity via Two-Phase Nanofluid Concept

“…They found that undulations on the cold wall improve the heat transfer rate. Considering the wavy wall forms, the entropy generation [22,23], non-uniform heating [24], partially heated wall [25,26], and micropolar fluids [27] have been investigated in recent years.…”

Effects of Entropy Generation, Thermal Radiation and Moving-Wall Direction on Mixed Convective Flow of Nanofluid in an Enclosure

“…The entropy generation is expressed by two quantities, i.e., heat transfer (first term in below equation) and liquid friction (last term in below equation) [18,21,22,34].…”

“…Nanofluids are pioneering fluids in the field of thermal science and it has been used actively to analyze the energy transport in thermal systems [16][17][18][19][20][21][22]. Sheremet et al [21] discovered the buoyant flow and entropy generation of nanoliquid in a closed box with variable border temperature.…”

“…Alsabery et al [22] numerically explored the entropy generation and convection of nanoliquid in a wavy walled box. Santra et al [23] deliberated the energy transfer augmentation of a water-copper nanoliquid in a differentially heated box.…”

Numerical Simulation on Convection and Thermal Radiation of Casson Fluid in an Enclosure with Entropy Generation

“…It is an essential aspect of the 2nd law of thermodynamics [ 21 , 22 ]. The study of entropy generation in closed domain has been analyzed in several studies [ 23 , 24 , 25 ]. Ahmed et al [ 26 ] analyzed the entropy production due to doubly diffusive convection of Casson liquids in the occurrence of slip boundaries and chemical reactions.…”