Enhanced heat transmission in a triangular enclosure with a rotating cooled wall using Nano-Encapsulated Phase Change Material nanofluid under mixed convection

Maximizing heat transfer rates within enclosed cavities is of paramount importance in various engineering applications. This study focuses on enhancing heat transmission efficiency through forced convection within a triangular cavity containing a rotating cylinder. The approach involves incorporating Nano-Encapsulated Phase Change Material (NEPCM), applying a uniform magnetic field, and introducing a cold, dynamically rotating cylinder. The cavity's configuration maintains an elevated temperature on the upper wall while the inclined side walls remain cold. The investigation also explores the impact of varying the position of the rotating cylinder within the cavity. Mathematical modeling is undertaken using the Galerkin finite element methodology. Numerical results reveal a direct proportionality between the Nusselt number (Nu) and the Darcy number (Da), as well as an inverse proportionality between Nu and the Hartmann number (Ha). Elevating the Darcy number from 10⁻⁵ to 10⁻² leads to a 54% increase in the Nusselt number, while increasing the Hartmann number from 0 to 100 results in a 12.5% decrease in Nu. Intriguingly, positioning the cold rotating cylinder in the upper enclosure leads to a 240% enhancement in Nu. This study highlights the intricate interplay of geometry and external fields in optimizing heat transfer within complex cavities.