False diffusion, asymmetrical interface, and equilibrious state for pure solid-gallium phase change modeling by enthalpy-porosity methodology

Literature survey showed that three important and key scientific problems including: i) the mechanisms or underlying causes of the discrepant sources, especially at the top phase interfaces, are yet to be investigated, which are crucial to recognize the validation of the numerical technology for metal isothermal phase-change applications. Moreover, revisiting the well-known experiments in literature, they did ii) not display the interface shape under the conditions of aspect ratio = 0.714 & Stefan number = 0.0391 at the dimensionless time of 0.0184, but also iii) not discuss the equilibrium state of pure solid‑gallium phase change. Therefore, it is a fascinating and interesting concern that what happened for these two kinds of important problems or key questions ii) and iii). Here, all above-mentioned three problems i) to iii) are explored and addressed by finite-volume-based enthalpy-porosity methodology. The core findings in this work are that: i) The novel mechanisms of convective false diffusion are revealed and clarified for enthalpy-porosity modeling solid-liquid interface of pure solid‑gallium melting; ii) The novel phenomena of asymmetrical solid-liquid interface are found and explained for a large aspect ratio of 0.714; iii) The innovative findings and fitting correlations are discussed by extended literature’s study to phase-change equilibrium state, and it is comprehensively demonstrated that the dimensionless correlation of mean liquid layer thickness is equivalent to that of global liquid volume fraction. •Clarify novel mechanisms of convective false diffusion in modeling phase interface.•Explain novel phenomena of asymmetrical interface even if geometry & boundary conditions are symmetric.•Extend literature's study with innovative findings of phase-change equilibrium state.•Find correlation of mean liquid layer thickness closes to that of liquid fraction.