Improvement of Numerical Simulation for Melting of the Composite Phase-Change Material Based on the Comparison with Experiment

The addition of a metal skeleton significantly improves the heat storage/release rate of composite phase-change materials (PCMs), taking as a critical factor in extending their application potential. When the numerical simulation with conventional thermal equilibrium model is used for high computational efficiency, its applicability is constrained in scenarios requiring precise characterization of heat transfer. To improve the simulation accuracy, the concept of contact thermal resistance, which refers to the heat transfer resistance between two adjacent objects, is introduced to construct the local thermal nonequilibrium (LTNE) model in the article. A V-shaped nonuniform skeleton is proposed by combining several single-directional gradient units. The comparison of numerical simulation with experimental results shows that the improved LTNE model achieves higher accuracy, with optimal agreement at a contact thermal resistance of 2.5 × 10⁻⁴ m² K W⁻¹. The average relative error in total melting time with experimental data is significantly reduced from 16.67% to 2.00%, compared with the conventional thermal equilibrium model. The V-shaped nonuniform skeleton is superior to the uniform skeleton with a reduction of 29.41% in melting time. This study provides an effective way to establish an accurate model of the melting process of composite PCMs.