Melting and solidification of binary mixtures with double-diffusive convection in the melt
Abstract
A combined experimental and numerical study is performed of double-diffusive convection during solid/liquid phase-change of binary mixtures in vertical cavities. In both the melting and solidification experiments, it is found that the phase-change processes induce double-diffusive layers and plumes in the liquid. These flow structures have a profound influence on the phase-change process itself. The presence of double-diffusive layers can cause abrupt changes in the phase-change rates as well as remelting or resolidification in parts of the system. Mathematical models are developed to simulate melting and dendritic solidification in binary systems. With these models, it has been possible to predict the double-diffusive layering phenomena in the liquid and their effects on the phase-change processes. While the predictions of the model for melting in binary systems compare favorably with the experimental data, there is considerable disagreement between the results of the model for dendritic solidification and the experimental measurements. The reasons for this disagreement as well as future research needs for modeling solidification of binary mixtures are identified.
Degree
Ph.D.
Advisors
Viskanta, Purdue University.
Subject Area
Mechanical engineering
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