<p>This paper presents a comprehensive modeling framework for turbulent flow and phase-change phenomena in porous media. The study revisits the <i>double-decomposition</i> concept for macroscopic turbulence modeling, where instantaneous variables are averaged in both time and space, leading to distinct forms of the governing equations. The model extends the “One-Energy Equation Model” to simulate melting and solidification of pure substances and alloys, treating the solid phase as a porous medium with low porosity and permeability. During phase transition, thermal equilibrium is assumed in the mushy zone, while viscous and form drag effects are adjusted based on temperature. The latent heat is treated implicitly in the energy equation, and the liquid fraction is updated iteratively. Numerical solutions employ the <i>SIMPLE</i> algorithm with the <i>Strong Implicit Procedure</i> for inner iterations. Validation against existing literature demonstrates the model’s accuracy for pure substances.</p>