Performance assessment of nano‐enhanced phase change materials for natural convection and entropy generation under thermal radiation influence

The study explores free convection and the thermal performance of a nano‐encapsulated phase change material (NEPCM) suspension within a square enclosure containing a heated block, with a focus on the influence of thermal radiation. Additionally, it investigates entropy generation under the effects of thermal radiation. The enclosure is configured with the left and right walls maintained at a constant cold temperature ( T c ), while the top and bottom walls are insulated to prevent heat exchange. At the center of the cavity, a square block is uniformly heated to a constant temperature ( T h ). The study employs the finite volume method with Gauss–Seidel and sub‐relaxation for solving dimensionless governing equations. The novelty of this work lies in introducing a cavity with a centrally heated block under radiative conditions, while simultaneously evaluating entropy generation. Such a combined investigation of NEPCM, radiation, and entropy within a complex enclosure geometry has rarely been addressed in prior studies, thus filling an important gap in the existing literature. The key governing parameters are the Rayleigh number (Ra = 10 3 –10 6 ), radiation parameter (Nr = 0–1), and volume fraction of NEPCM (φ = 0%–5%). The findings indicate that incorporating NEPCMs stabilizes temperatures, reduces convective motion, and enhances thermal efficiency. Although increasing thermal radiation and nanoparticle concentration enhances the heat exchange rate, higher Nr raises average entropy generation, whereas increased nanoparticle concentration mitigates it.