Title£º Global heat transfer model and dynamic ray tracing algorithm for complex multiple turbine blades of Ni-based superalloys in directional solidification process
Author£º Wen Wang, Jian-xin Zhou, Zhao Guo, Ya-jun Yin, Xu Shen and Xiao-yuan Ji
Address£º State Key Laboratory of Materials Processing and Die &Mould Technology,Huazhong University of Science and Technology, Wuhan 430074, China
Key words£º radiative heat transfer; ray tracing; turbine blade; directional solidification; numerical simulation
CLC Nmuber£º TG146.1+5/TP391.9
Document Code£º A
Article ID£º 1672-6421(2019)05-326-10

High-quality solidification microstructure during directional solidification relies on precise temperature gradient control, so accurate calculation of the temperature field is critical. In this study, a 3D transient global heat transfer model of directional solidification by the Bridgman method based on the finite difference method is developed. The radiation heat in this model is calculated by the discrete transfer method, and a modified method of external surface area for irregular geometric models is proposed to reduce the zigzag shape caused by finite difference grids. Considering the radiative heat transfer between any surface elements of all materials in the directional solidification furnace, a dynamic ray tracing algorithm is developed to simulate the entire process of directional solidification. Then, the simulated results are compared with the theoretical results and experimental results, respectively. Finally, based on the present model and method, the simulation program developed is applied to the directional solidification of actual castings. The simulated results are in good agreement with the experimental results, which indicate that the model and method developed in this study is effective and practical.