An investigation of the solidification of a metal and two n-paraffins using an acoustic technique.

A novel acoustic technique is described for following the motion of the solid-liquid interface during the freezing of mercury, n-hexadecane and n-octadecane where heat transfer is unidirectional. It is shown that the actual amount of solidification occurring in a given time differs from that predicted using a numerical solution to the transient heat conduction problem. The differences are small for mercury but large for the paraffins. They are interpreted in terms of the nature of the solid-liquid interface. Furthermore the experimental and predicted temperature distributions in the liquid and solid phases differ. These differences are extremely small for mercury. The data for the three materials conform to a relationship observed previously according to which the thickness of the solidified layer is a linear function of the square root of time.