Geometrical modeling to improve the accuracy of drilled cooling holes on turbine blades

摘要

Film cooling represents one of most advanced technologies that facilitate the operation of gas turbine blades in today's high-thrust-to-weight-ratio gas engines. The accuracy of the film cooling holes in a turbine blade is of central importance to cooling performance. However, in all the state-of-the-art methods known for producing turbine blades with drilled holes, complexity in the manufacturing processes will inevitably cause unwanted consequences such as non-uniform deformation of turbine blades and fixture layouts, and resisting motions and deflections of workpieces during drilling. These manufacturing issues will cause deviations in the geometrical and positional parameters of drilled holes. In this paper, we propose a systematic methodology to establish an improved parameterized model for drilled cooling holes on turbine blades. The non-uniform deformation of turbine blades, including the wall thickness and shrinkage distribution, was established by deformation decoupling analysis; the surface error generated before and after machining was obtained using locating error analysis and finite element analysis (FEA). An accurate model for film cooling holes can be established by considering the process-induced deviations in geometry and positioning. The applicability of the proposed methods is validated using numerical simulation data and experimental results.