Abstract: A simple and efficient reversing methodology of adjusting featured parameters is proposed for the casting-die profile design of turbine blades. On the one hand, casting shrinkages at different positions of the blade are considered as nonlinear thermo-mechanical casting deformations that are calculated with accuracy by finite element analysis. On the other hand, twelve featured parameters describing the camber line and thickness of the blade profile are identified, analyzed and adjusted to counteract blade deformations. This method therefore exhibits its advantage over the traditional linear scaling method. As the reversing design of the die profile is directly based on the CAD parameterized model, the post-processing of surface smoothing and surface patching is no longer needed as compared with the existing mesh-based reversing method. By investigating the investment casting of a typical blade with chord length of 60.5 mm, the proposed method is compared with the linear scaling method and mesh-based reversing method. Results show that the die profile obtained can satisfy the design requirement more accurately. Compared with the traditional linear scaling method, the maximum profile error, the chord length error and the twist angle error of the blade decrease by 83.8%, 96.3% and 66.7%, respectively.

Key words: blade profile, featured parameter, investment casting, die profile, reversing design