材料期刊网

考虑炉壁温度的变化, 基于Monte Carlo射线追踪法建立了高温合金叶片定向凝固过程的温度场计算改进模型. 通过法向射线加密提高加热炉炉壁的辐射计算精度, 并采用叶片三维有限差分网格和加热炉二维网格混合使用的方法提高计算效率. 叶片和炉壁的温度曲线模拟与实验结果吻合良好, 改进模型反映了抽拉过程中炉壁温度的变化及其对叶片内部温度分布的影响, 提高了叶片温度的模拟精度.

Ni--based superalloy turbine blades produced by Bridgman directional solidification technology are widely used in both aeronautic and energy industries as key parts of the gas turbine engines. Because of existence of complex heat radiation between the shell surface and the furnace wall, precise control of the temperature distribution within the blade is a challenging task. A modified model based on the Monte Carlo ray tracing method was proposed for the three dimensional temperature simulation of the turbine blades during directional solidification process, in which the furnace wall temperature evolution was considered and calculated. Ray refinement in normal direction was applied to improve the heat radiation calculation precision. Three dimensional finite differential grids for turbine blades and two dimensional differential grids for furnace wall were used together to increase simulation efficiency and save memory consumption. Heat transfer calculation of the blades with the modified model was performed and compared with that of the simplified model in which the furnace wall temperature was treated as constant. Experiments were carried out to validate the proposed model in this paper. It was demonstrated that the modified model revealed the furnace wall temperature change during the withdrawal process and its impact on the blade, and simulated the temperature distribution of the turbine blade with a higher accuracy.