镍基高温合金多叶片定向凝固过程数值模拟

NUMERICAL SIMULATION OF DIRECTIONAL SOLIDIFICATION PROCESS OF MULTIPLE TURBINE BLADES OF Ni-BASED SUPERALLOY

建立了基于Monte Carlo法的射线追踪模型,并用来动态处理定向凝固抽拉过程中多叶片间以及叶片与加热炉间的辐射换热过程.模型中考虑了抽拉速度、加热炉几何尺寸等影响,研究了2种抽拉速度下的温度分布.得到的温度采样点冷却曲线与实际冷却曲线进行了对比并得到了较好的结果.多叶片条件下,冷却区叶片靠近炉壁的温度低于同一水平线上靠近炉腔中心部分的温度.抽拉速度为7.0mm/min时等温线的斜率高于抽拉速度为4.5 mm/min时的斜率.炉腔的几何尺寸对凝固过程温度分布有重要影响.

A ray tracing model was developed based on Monte Carlo method and used to deal with the complex heat radiation transfer among the multiple turbine blades and the furnace wall during the withdrawal process dynamically. The withdrawal rate and furnace geometry were considered in this model, and the temperature distributions during directional solidification process at two different withdrawal rates were investigated. The simulated cooling curves of special sample positions agreed well with the experimental ones. The temperature of the side of multiple blades close to the furnace wall is lower than that close to center of the furnace in horizontal section in cooling zone. The slope of cooling curve at withdrawal rate 7.0 mm/min is larger than that at withdrawal rate 4.5 mm/min. The geometry of furnace has great influence on the temperature distribution of directional solidification process.