Work

Thermal and flow dynamics of unsteady MHD nanofluid convection in a partially heated porous cavity

Year: 2025

Type: article

Abstract: This study numerical investigates unsteady freeconvection in a square permeable cavity, driven by magnetohydrodynamic flow of TiO 2 -H 2 O nanofluid. The cavity features partially heated vertical walls, with adiabatic bottom and inclined upper walls, a scenario with widespread applications in fields such as heating, ventilation, and air conditioning (HVAC), electronic cooling, solar collectors, building insulation, automotive engineering, geothermal energy, and aerospace technology. The governing equations are discretized using the Marker and Cell (MAC) method, with spatial discretization achieved through the finite difference technique. A staggered grid system is employed to enhance stability and accuracy, and the resulting equations are solved iteratively to capture the unsteady behavior of the system.The study examines the range of Darcy number $$\left( {10^{ - 1} \le {\text{Da}} \le 10^{ - 3} } \right),$$ 10 - 1 ≤ Da ≤ 10 - 3 , Rayleigh number $$\left( {10^{3} \le {\text{Ra}} \le 10^{6} } \right),$$ 10 3 ≤ Ra ≤ 10 6 , Hartmann number $$\left( {10 \le Ha \le 30} \right),$$ 10 ≤ H a ≤ 30 , Prandtl number $$\left( {\Pr = 6.2} \right),$$ Pr = 6.2 , inclined magnetic field inclination angle $$\left( {\gamma = \frac{\pi }{6},\frac{\pi }{4},\frac{\pi }{3}} \right),$$ γ = π 6 , π 4 , π 3 , heat source/sink parameter $$\left( { - 6 \le Q \le 6} \right)$$ - 6 ≤ Q ≤ 6 . Parametric modeling explores, streamline and isotherm plots reveal rising $${\text{Ra}}$$ Ra enhance heat transfer, while increased Darcy numbers intensify fluid flow and broaden temperature gradients. Larger heat source/sink parameters expand isotherm contours, amplifying convection. Validation against prior studies confirms the model's reliability and provides insights into the intricate thermal dynamics of the system.

Source: Journal of Thermal Analysis and Calorimetry

DOI: 10.1007/s10973-025-14025-x

Authors: S. Vigneshwari, B. Reddappa, A. Sumithra, B. Rushi Kumar, Hakan F. Öztop