A Two-Wavelength Holographic Interferometry Study on the Solidification of a Binary Alloy Around a Horizontal Pipe

Abstract

An experimental study on the transient outward solidification of a transparent binary alloy from an internally cooled horizontal pipe is reported in this paper. Two-wavelength holographic interferometry was used to visualize the density field in the liquid phase and to measure the local heat and mass transfer rates at the mush/liquid interface at characteristic times, Stefan numbers, and initial concentrations. The presence of double diffusive convection in the liquid phase greatly affected the local Nusselt and Sherwood numbers. The dependence of the pipe wall temperature, the solidified volume fraction, and the shape of the solid/mush and mush/liquid interfaces on the Stefan number, time, and initial concentration were also determined. The flow field in the liquid phase was visualized with the help of shadowgraphs. Interface photographs presented in this paper demonstrate the effect of the initial concentration on the structure of the mush/liquid interface, which varies from rather smooth to highly dendritic.