  While significant interests have been devoted to the double diffusive phase
change heat transfer of binary solutions, the understanding on the melting heat
transfer of salty ice in porous media is still imcomplete. This work aims to
explore the melting heat transfer characteristics of salty ice in a square
cavity filled with homogeneous porous media subjected to lateral heating. In
order to facilitate the visualization of melting dynamics in a uniform porous
media, a three-dimensional (3D) printed transparent cavity filled with porous
matrix was manufactured, featuring an open upper end. Aqueous solutions of
sodium chloride at concentration both higher and lower than the eutectic
concentration were investigated. Lateral heating experiments with constant heat
flux were conducted in a subzero temperature environment. The effect of heating
power, initial concentrations and different sizes of porous matrix was
investigated. Distinct phenomena were observed based on the concentration of
the aqueous solution. Specifically, the concentration lower than the eutectic
concentration results in an upward bending melting interface. Whereas the
concentration surpassing the eutectic concentration resulted in a downward
bending melting interface. In the presence of salt, a melting convex appears at
the bottom of the melting interface and manifests during the whole melting
process. Notably, smaller matrix enables faster melting rate. Furthermore,
three distinct stages were revealed in our experiments, characterized as
conduction, mixture of conduction and ultimately convection stage. The
correlations for Nu and the average propagation rate of mushy/liquid interface
were established by order of magnitude analysis and fit well with the
experiments.
