Constructing 3D fan blade models in CAD-system on the basis of coordinate measuring techniques

Methods of coordinate measurement are reviewed and a possibility of their usage for fan blade geometry characterization and construction of a 3D CAD model is evaluated with account for actual blade airfoil deviations. Different components of blade geometry deviation from nominal geometry are considered. A technique of constructing a 3D model in a CAD-system on the basis of coordinate measurement, considering real manufacturing deviations of an airfoil is presented. To allow deformation of the nominal model according to the measurement data, the nominal model of the airfoil was recreated with account for the location of the measured sections. The issue of adding the measured profile of the blade root, edges and the peripheral area of the airfoil to the model is discussed. The influence of deviations of the out-of-the-flow path profile on the mechanical characteristics is assessed. A model with maximum and minimum deviations possible was constructed. Expected displacements and natural frequencies of the model were compared to the nominal ones. Further direction of investigation to determine airfoil geometry parameters most efficient for robust optimization is presented.