Topology‐Guided Melting Optimization in CuO‐Doped Phase Change Media: A Numerical Framework for Thermal Storage Enhancement

This study numerically examines the melting and thermal storage performance of RT42 paraffin phase change material (PCM) integrated with 4 wt% CuO nanoparticles under five heated wall geometries and a reference case. A two‐dimensional rectangular enclosure (50 mm × 100 mm) is laterally heated at 1000 W m −2 , with other walls insulated. The CuO nanoparticles enhance PCM conductivity from 0.15 to 0.45 W/m·K, accelerating melting and heat transfer. Using the enthalpy‐porosity model, buoyancy‐driven melting is resolved with <2% deviation in validation and grid independence at 0.8 mm. At 7000 s, Cases IV–V attain 98–100% liquid fraction versus 85% in the reference geometry, while stored energy peaks at 42 kJ—about 25% higher than the baseline (33.5 kJ). Case V achieves a domain‐average temperature of 305.1 K, compared with 303.8 K for the reference, confirming more complete melting. Extended and inclined wall designs induce multi‐cell convective vortices that improve thermal uniformity and enhance the charging rate. The findings establish that optimized wall geometries, combined with CuO‐enhanced PCM, significantly improve heat absorption, melting uniformity, and energy storage efficiency, making the system ideal for solar, electronic, and battery‐cooling thermal management.