Solidification performance of nanoparticle-augmented PCM in finned cavities: A galerkin method investigation

• Numerical study of freezing in elliptical finned chamber with nanoparticle additives • Particle shape factor reduces solidification time by up to 6.96% • Higher nanoparticle fractions shorten freezing time by as much as 26.78% • Optimized case completes freezing in 463.92 s vs 633.62 s with pure water This work delivers a detailed numerical analysis of the solidification characteristics of a phase change material (PCM) housed in an elliptical cavity outfitted with internal fins, designed to boost the efficiency. The setup integrates extended heat-transfer surfaces with dispersed nanopowders to accelerate heat removal and enhance the freezing process. The influence of nanoparticle geometry—represented by the shape factor (m)—alongside the particle volume fraction (ϕ), is systematically evaluated to determine their roles in governing solidification dynamics. The conservation equations for mass, momentum, and energy are solved using a robust computational framework that employs adaptive mesh refinement to accurately resolve the sharp gradients at the moving solid–liquid interface within the elliptical domain. The findings show that increasing the shape factor (m) shortens the freezing duration by about 3.94%–6.96%, depending on the nanoparticle loading. Likewise, higher nanoparticle volume fractions (ϕ) significantly increase the effective thermal conductivity, cutting the total solidification time by up to 26.78%. Compared with the reference case using pure water, the optimized configuration achieves full solidification in 463.92 seconds, rather than 633.62 seconds. Overall, the combined use of fin-induced conduction and nanoparticle-enhanced thermal transport demonstrates strong potential for developing compact, high-performance cold thermal storage technologies relevant to industrial applications and renewable energy systems.