Fixed-Grid Modeling of Solid-Liquid Phase Change in Unstructured Meshes Using Explicit Time Schemes

Abstract

Fixed-grid enthalpy models have been used extensively for solid-liquid phase-change computational fluid dynamics (CFD) simulations with implicit time schemes. In this work, this technique is implemented for explicit time schemes and collocated unstructured domain discretization, due to the interest in coupling phase-change formulations with turbulence models for liquid motion.

Issues regarding the form of the energy equation, the treatment of the pressure equation, as well as the momentum source term coefficient introduced by the enthalpy-porosity method are described in detail.

Numerical implementation is tested with different study cases, showing good agreement with other experimental and numerical results.

Acknowledgments

This work has been financially supported by the Ministerio de Economía y Competitividad, Secretaría de Estado de Investigación, Desarrollo e Innovación, Spain (ENE-2011-28699), by Termo Fluids S.L., by the Secretaria d'Universitats i Recerca (SUR) del Departament d'Economia i Coneixement (ECO) de la Generalitat de Catalunya, and by the European Social Fund.

Notes

¹Actually, in those references, h represents only the sensible enthalpy and an extra source term is included to account for the latent enthalpy, which is represented by ΔH.

²This results from the assumption of constant specific heat in the liquid phase, and from the incompressibility condition [Eq. (1)]. In a more general formulation the total liquid enthalpy should be used in the convective term. If the incompressibility condition were not applied, the latent heat of the liquid phase should be included. However, this remains different from advecting the enthalpy h (as defined here), because the latter is a mean value of the enthalpies of the liquid and solid phases present in the control volume.