Three-dimensional Design Optimization for Fir-tree Root of Turbine Blade with Finite Element Method

摘要

Fir-tree root is widely used inblades of gas turbine and large power steam turbine. The structure of root and rim affects the security of the entire blade to a certain extent. Based on the parametric design language APDL, the fir-tree root and rim with complex three-dimensional contact stress, are numerical studied and optimized with multi-variable using the finite element software ANSYS. The zero-order optimization algorithm and the first-order optimization algorithm are combined in the optimization process to enhance the credibility of results. A novel structure of the turbine blade fir-tree root and rim is then obtained. Moreover, numerical results show that equivalent stress has a reduction after the multi-variable optimization when the maximum equivalent stress of root is set as the objective function. Compared with the results of the initial design, the maximum equivalent stress of the root of the optimized design reduces by 4.56%, and the maximum equivalent stress of the rim reduces by 4.40%. Relevant results are expected to support the design of turbine blade in theory and then improve the operation reliability of turbo-machinery to some extent.