  In this paper, an enthalpy-based multiple-relaxation-time (MRT) lattice
Boltzmann (LB) method is developed for solid-liquid phase change heat transfer
in metal foams under local thermal non-equilibrium (LTNE) condition. The
enthalpy-based MRT-LB method consists of three different MRT-LB models: one for
flow field based on the generalized non-Darcy model, and the other two for
phase change material (PCM) and metal foam temperature fields described by the
LTNE model. The moving solid-liquid phase interface is implicitly tracked
through the liquid fraction, which is simultaneously obtained when the energy
equations of PCM and metal foam are solved. The present method has several
distinctive features. First, as compared with previous studies, the present
method avoids the iteration procedure, thus it retains the inherent merits of
the standard LB method and is superior over the iteration method in terms of
accuracy and computational efficiency. Second, a volumetric LB scheme instead
of the bounce-back scheme is employed to realize the no-slip velocity condition
in the interface and solid phase regions, which is consistent with the actual
situation. Last but not least, the MRT collision model is employed, and with
additional degrees of freedom, it has the ability to reduce the numerical
diffusion across phase interface induced by solid-liquid phase change.
Numerical tests demonstrate that the present method can be served as an
accurate and efficient numerical tool for studying metal foam enhanced
solid-liquid phase change heat transfer in latent heat storage. Finally,
comparisons and discussions are made to offer useful information for practical
applications of the present method.
