Automatic Creation of Blending Surfaces in Hydropower Generators Turbine Blades

Abstract

Hydropower generators turbine blade is a one of kind product that requires specific maintenance. They are designed in very specific software tools based on features, which allow good CAD/CAE automation by simply tweaking parameters. However, such CAD/CAE automation has brought an undesired side effect: it's hard to add new features that are not considered in the original CAD. Specially in simulation-optimization applications, where parameters that are not considered in the design must be modified. This is the case in this work, where fluid-structure analysis is performed and a geometric feature that transcend the design activity (blending surface between the crown and the blade) is modified. This paper describes an ongoing project which involves the implementation of a module able to intercept the geometry generated by a CAD program using the IGES format, create/modify a new geometric feature and update the fluid volume and blade geometries. The surface boundary curves are extracted, and the adjacency relationship between the surfaces is determined by coordinate numerical comparison. The surfaces are coherently oriented and the solid models are completely determined. Using the de Boor's algorithm and the surface orientation a model with exclusive triangular faces coherently oriented is created, and then the blending surface is automatically created. The refined mesh for the models are created and fluid-structure analysis is performed for the simulation-optimization.