The advancement in research, production, and use
of nanofluids presents an opportunity for improving natural convective heat
transfer in cavities. This study involves the numerical investigation of the
natural convection in a two-dimensional hexagonal cavity fitted with a square
obstacle and filled with a ternary hybrid MgO-ZnO-SiC/ethylene glycol nanofluid
under steady state conditions. The research considered the effects of Rayleigh
number, inclination angle, and aspect ratio on heat transfer and fluid flow in
a bid to enhance thermal efficiency in the complex geometry. The governing
Navier-Stokes equations were solved using the Finite Element Method in COMSOL
Multiphysics. The model was first validated against benchmark results for
natural convection in a differentially heated square cavity for reliability and
accuracy. Additionally, the grid independence validation agrees with results
literature which is an affirmation of the correctness of the numerical model.
The results showed a strong transition from conduction to convection heat
transfer as the Rayleigh number increased. Higher Rayleigh numbers produced
stronger buoyancy-driven circulation, thinner thermal boundary layers, and
appreciably high Nusselt numbers. . The average ,
,
,
, ,
and were 0.2757449 W/m·K, 2146.9702 J/kg·K,
0.0169729 Pa·s, 137.60446 kg/m³, m²/s, and K-1, respectively. At and ,
Nu values were 4.20, 4.12, 4.15, 4.22, and 4.25, respectively. At and ,
Nu values were 5.48, 5.40, 5.42, 5.50, and 5.55, respectively. For and AR values of 0.25, 0.3, 0.35, and 0.40, Nu
values were 3.50, 3.58, 3.65, and 3.75, respectively. At ,
and AR
values of 0.25, 0.3, 0.35, and 0.40, Nu values were 3.55, 3.62, 3.70, and 3.82,
respectively. At ,
and AR
values of 0.25, 0.3, 0.35, and 0.40, Nu values were 4.05, 4.20, 4.40, and 4.65,
respectively. At ,
and AR
values of 0.25, 0.3, 0.35, and 0.40, Nu values were 4.70, 5.10, 5.55, and 6.00,
respectively. The results provide
important new information for the design and optimization of passive cooling
applications and natural convection-based thermal management systems using
ternary hybrid nanofluids.
