Natural Convective Heat Transfer Rates During the Solidification and Melting of Metals and Alloy Systems

Analysis of experiments involving a cylindrical column of lead in the process of freezing downward or alternatively, of melting upward from the base of the container, showed that heat transfer rates associated with Benard convection are less under transient conditions than at steady-state. Analysis of experiments involving the freezing of lead-tin alloys (0.2 – 1.6 wt. percent Sn) showed that the same heat transfer correlation for Benard convection could be applied, provided the upper bounding “interface” was located on the solidus isotherm for planar and cellular alloy growth, and on the liquidus, for cellular-dendritic alloy growth.