Continuum modeling and experimentation for solid-liquid phase change in binary systems with natural and mixed convection
Abstract
Semi-empirical laws and microscopic descriptions of transport behavior have been integrated with principles of classical mixture theory to obtain a set of continuum conservation equations for binary, solid-liquid phase change systems. A widely accepted finite-difference scheme has been extended to accommodate the multiconstituent phase change process and used to solve the continuum equations. Numerical calculations have been performed for a binary aqueous ammonium chloride solution in both open and closed configurations and supplemented by bench scale experimental verification and comparison with previous qualitative experimental results. Advective transport of water enriched interdendritic fluids across the permeable liquidus interface has been identified as the primary mechanism for macroscopic species redistribution. The extent of this penetration is governed by the relative strengths of solutally driven mushy region flows and flows established in the bulk fluid by either natural or externally induced means. The redistribution of species which accompanies the mushy region outflow has been shown to significantly affect subsequent phase change behavior, contributing to localized growth rate variations, the formation of channel segregates, and the establishment of irregular liquidus front morphologies.
Degree
Ph.D.
Advisors
Incropera, Purdue University.
Subject Area
Mechanical engineering
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