A MATHEMATICAL MODEL OF HEAT TRANSFER AND FLUID FLOW IN THE DIRECT CHILL CASTING OF AZ31 MAGNESIUM BILLETS

摘要

A 2-D axisymmetric mathematical model of heat transfer and fluid flow during direct chill (DC) casting of AZ31 magnesium billets was developed using the finite volume modeling package FLUENT. Model boundary conditions were based on those used in a 2-D axisymmetric finite element model previously developed in ABAQUS, which approximates the effects of fluid flow by manipulating material properties. Materials properties were based on literature and knowledge of the physical phenomena occurring during the DC casting process. Temperature predictions from both models are compared with plant trial temperature data acquired from billets produced with different casting conditions at Timminco Metals in Haley, Ontario. Following initial comparison using identical material properties and boundary conditions, the high temperature material properties and primary mould cooling boundary condition of the FLUENT model were altered to fit the measured temperatures. The significance of fluid flow on the apparent material properties of AZ31 and the thermal boundary conditions is presented.