AN INVERSE HEAT CONDUCTION MODEL FOR DETERMINING THE CASTING/CHILL INTERFACIAL HEAT TRANSFER COEFFICIENT

Abstract

The interfacial heat transfer coefficient (IHTC) is required for accurate simulation of the casting process. However, it cannot be easily obtained simply by using either experimental or theoretical methods. Using measured temperature data, an inverse method can be used to predict the IHTC. However, the latent heat released during the solidification of a molten metal complicates the associated temperature and IHTC calculations. To overcome this difficulty, an equivalent specific heat method is applied in this study to calculate the IHTC for the casting process. It is found that the identified IHTC varies with time during castings solidification. The IHTC values calculated for an aluminum alloy casting of simple geometry cast on a steel chill vary from 1200 to 3500 W·m−2·K−1. Application of the indentified IHTC in the forward heat conduction model with the same boundary condition allows comparison between numerically calculated and experimentally obtained results for validation of the method. The results show that the numerically calculated temperatures are in good agreement with those measured experimentally. This confirms that the proposed method is a feasible and effective tool for determining the casting-mold IHTC. Additionally, the characteristics of the time−varying IHTC have also been discussed.