Application of control volume finite element method to phase change problems during DC casting

摘要

In this paper,two-dimensional phase change problems during the start-up stage for DC (Direct Chill) casting of a rectangular aluminum ingot are solved using the control volume finite element method (CVFEM).An enthalpy formulation is adopted to express the integral form of conservation of energy on an arbitrary domain,using liquid fraction to prepresent the liquid region,the mushy zone and the solid region.Boundary conditions such as specified heat flux/temperature or convection are considered in an enclosed mathermatical model.Details of implementing the CVFEM on the presented model are described.The solution procedure is first verified by solving heat conduction problems for which exact analytical solutions are available.Then it is applied to predict the solidification pattern of an aluminum alloy ingot which is growing at a prescribed casting speed.The deforming grid technique,in which the element number is fixed while the element size is increasing with the computation proceeding,is employed to account for the continuous growth of the calculation domain.The good agreement was obtained between computations and some experimental measuremnets.