Numerical Investigation on the Melting Acceleration of Nanomaterial‐Dispersed Phase Change Materials in a Hemispherical Container

This numerical study addresses the critical challenge of sluggish melting rates in phase change materials (PCMs) utilized as thermal energy storage mediums. The primary goal of this investigation is to systematically evaluate and compare the thermal performance enhancement of dispersing various nanomaterials (TiO 2 , Fe 3 O 4 , Al 2 O 3 , SiO 3 , and CNTs) at multiple concentrations (1%, 5%, and 10%) inside a hemi‐spherical container. To achieve this, the enthalpy‐porosity method within ANSYS/FLUENT 16 was employed to simulate the transient, laminar, and unsteady phase‐change process under a constant external heating source of 87°C. The main novel contribution of this work lies in the detailed geometric optimization and comparative analysis of multi‐nanoparticle thermal and fluid dynamics within a hemispherical configuration, a design highly relevant for solar thermal conversion and electronic cooling but scarcely explored in hybrid formulations. Important outcomes revealed that the incorporation of nanomaterials substantially accelerated the melting front and minimized adverse thermal stratification. Notably, CNTs at a 10% concentration demonstrated the most superior performance, achieving complete melting within 20–25 min—a reduction of over 25% compared to pure PCM—while inducing maximum fluid velocities of 0.35 m/s and core temperatures near 340 K due to their exceptional thermal conductivity (4000 W/mK). Other nanomaterials like Fe 3 O 4 and Al 2 O 3 also exhibited promising enhancements, surpassing melt fractions of 0.8 within 30 min at 10% loading. The findings establish that optimizing nanoparticle type and concentration provides a strategic approach for maximizing the efficiency of latent heat thermal energy storage systems.