Turbine blades are designed to achieve its maximum efficiency, but deformations caused by the exposition to extreme operating environments provokes reduction in the engine performance. Often, operators choose to repair a damaged blade instead of replacing it to save money, however, reconstructing its virtual model, commonly the first step in the repairing process, can be challenging due to the geometrical complexity of the blades, variability in deformations and the requirement to meet the dimensions specified by the manufacturer. This paper presents the reconstruction methodology of the virtual model of a steam turbine blade through numerical tools and minimal parameters. First, few cross-sectional airfoil profiles are extracted from the damaged blade and are regenerated using Bernstein polynomials; then, using the previously obtained data, many more profiles are interpolated and stacked along the spanwise direction of the blade via Transfinite Interpolation in order to obtain a smooth and continuous representation of the reference blade.&nbsp; Final maximum deviation between the reference and reconstructed model resulted in an average value of&nbsp; 0.0192 and 0.0007 mm (or&nbsp;1.642 E- 03 %&nbsp;and 3.8418x10-3&nbsp;%&nbsp;) relative to the rotor diameter in the pressure and suction sides respectively, showing an accuracy that could be considered in real world industrial applications.&nbsp;

Reconstruction of a Steam Turbine Blade Using Piecewise Bernstein Polynomials and Transfinite Interpolation

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

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