Research Initiation Award: An Experimental and Theoretical Investigation of Convective Heat and Mass Transfer During Solidification of a Metal Alloy

摘要--美国国家科学基金会要求CTS 9308359普雷斯科特资助一项旨在提高对二元金属合金固-液相变过程中对流输运现象的理解的研究计划的启动。由于动量、热量和物质的传输对凝固材料中的冶金结构、化学均匀性、空洞的形成和夹杂物的捕获有很大的影响，相变过程的改进取决于对伴随的传输现象的详细了解。由于微观和宏观现象之间的耦合，二元固-液相变过程进一步复杂化，这将在拟议的项目中进行研究。提出了一种实验和理论相结合的方法来研究金属合金中的输运现象。这项研究的实验部分将利用中子照相技术对钢锭截面进行实验后的化学分析，并获得相变期间物种重新分布的实时记录。研究的理论部分将包括基于连续介质模型的数值计算，以解释两相(糊状)区域的随机行为和非平衡效应，如过冷和再燃。

ABSTRACT -- CTS 9308359 Prescott Funding is requested from NSF to support the initiation of a research program aimed at improving the understanding of convective transport phenomena during solid-liquid phase change of binary metal alloys. Since the transport of momentum, heat, and species strongly influence the metallurgical structure, chemical homogeneity, formation of voids, and entrapment of inclusions in solidified materials, improvements in phase change processes depend on having a detailed understanding of the attendant transport phenomena. Binary solid-liquid phase change processes are further complicated by coupling between micro- and macro-scale phenomena which is to be examined in the proposed project. A combined experimental and theoretical approach is proposed to study transport phenomena in metal alloys. The experimental portion of the study will utilize neutron radiography to perform post-experimental chemical analyses of ingot sections, as well as to obtain real-time records of species redistribution during phase change. The theoretical portion of the study will involve numerical computations based on a continuum model to account for stochastic behavior of the two phase (mushy) region and non-equilibrium effects, such as undercooling and recalescence.