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一、引言铸件凝固过程中,铸造合金和铸型都要发生一系列复杂的物理化学变化,因此影响凝固过程的因素很多。其中主要有:铸件的大小和形状;铸造合金成分及其热物性参数;铸型热物性参数;铸造合金与铸型间的边界条件和界面作用;铸型与环境间的边界条件;熔炼、浇注和铸型工艺等。为了使用计算机数值模拟法正确模拟,研究铸件的凝固过程,必须确切把握凝固过程的各个影响因素。其中不少因素,如热物性参数和界面换热系数,在凝固过程中还随时间而变,而实测这些参数又常很困难。为简化数值模拟的计算,有人常把这些参数作为常数处理,而不同文献所录用的数值往往还差别较大。实践证明,如果这些影响因素处理不当,
I. INTRODUCTION In the process of solidification of castings, a series of complicated physicochemical changes occur in the cast alloy and the castings, so there are many factors that affect the solidification process. Among them are: the size and shape of the casting; casting alloy composition and thermal properties of parameters; thermal properties of the mold parameters; casting alloy and the boundary conditions between the mold and the interface; boundary conditions between the mold and the environment; melting, pouring And mold technology. In order to simulate correctly using computer numerical simulation method and to study the solidification process of castings, it is necessary to know exactly all the factors that influence the solidification process. Many of these factors, such as thermophysical properties and interfacial heat transfer coefficients, also change with time during the solidification process, and it is often difficult to measure these parameters. In order to simplify the calculation of numerical simulation, some people often deal with these parameters as constants, and the values recorded in different literatures often differ greatly. Practice has proved that if these factors are not handled properly,