重型燃机导向叶片定向凝固过程数值模拟

Numerical Simulation on Directional Solidification Process of Heavy-duty Gas Turbines Guide Blade

文章采用ProCAST数值模拟软件对某重型燃机高温合金导向叶片定向凝固过程的温度场和晶粒组织形成过程进行数值模拟,研究不同的抽拉速率对叶身糊状区和柱晶组织的影响,确定最佳抽拉速率,并根据模拟结果开展了导叶片铸造工艺的研究.结果表明:数值模拟结果与试验结果吻合.采用将外橼板四边分别与四个引晶块相连,并将叶身下端面延长的方法可获得致密和均匀柱状晶组织的重型燃机导向叶片.在定向凝固过程中,抽拉速率的大小显著影响温度场的分布和晶粒的生长.通过模拟凝固界面的形态变化,可以确定最佳抽拉速率.

In this paper, the temperature field and structure formation process of heavy duty turbine superalloy guide blades in directional solidification are simulated by ProCAST numerical simulation software, the effects of different withdrawal rates on the paste zone and the growth of columnar grains are studied, the best withdrawal rate is determined. According to simulation results, the research on the casting process of the blade has been carried out. The results show that the numerical simulation results are in good agreement with experimental results. The guide blades with the compact and uniform columnar grains can be obtained with the method of using four seeding blocks connecting with the blade edges and extending the end of the blade. The temperature fields and the growth of columnar grains are effected by withdrawal rate in the directional solidification process. the best withdrawal rate is determined by simulating the morphological changes of solidification interface.