Interferometric measurements of a dendritic growth front solutal diffusion layerAn experimental study was undertaken to measure solutal distributions in the diffusion layer produced during the vertical directional solidification (VDS) of an ammonium chloride - water (NH4Cl-H2O) solution. Interferometry was used to obtain concentration measurements in the 1-2 millimeter region defining the diffusion layer. These measurements were fitted to an exponential form to extract the characteristic diffusion parameter for various times after the start of solidification. The diffusion parameters are within the limits predicted by steady state theory and suggest that the effective solutal diffusivity is increasing as solidification progresses.
Hopkins, John A. (Tennessee Univ. Tullahoma, TN, United States)
Mccay, T. D. (Tennessee Univ. Tullahoma, TN, United States)
Mccay, Mary H. (Tennessee, University Tullahoma, United States)