基于θ映射法的燃气涡轮叶片高温蠕变变形分析

High temperature creep deformation analysis of gas turbine blade based on θ-projection method

采用θ映射法对镍基定向凝固合金DZ408不同温度下的纵向蠕变行为进行数值模拟,其结果与试验数据吻合较好。同时,针对叶片三维有限元分析需要,将单轴蠕变方程进行了多轴拓展,并将其编制成用户子程序植入ABAQUS商用有限元软件。采用该方法对航空发动机60 h持久试车过程中涡轮叶片的高温蠕变进行模拟,得到的叶尖残余变形与试验后实际伸长量接近,验证了方法的有效性,表明本方法能够为涡轮叶片的蠕变变形及叶尖间隙设计提供参考。

The θ-projection method was used to characterize the longitudinal creep deformation of a Ni-base direactionally solified alloy DZ408 under different temperature and stress levels. The calculation results matched well with test results. In order to carry out 3D finite element analysis, the single axial equations of the θ-projection method were developed into multi-axial form which was then implemented into ABAQUS/UMAT as a user material subroutine. The high temperature creep deformation of a gas turbine blade in 60 hours engine durability test was simulated using this method. The residual deformation of blade tip is approximately equal to actual elongation to prove that the method is valid. The method could be provided as reference for turbine blade creep deformation and tip clearance design.