Parametric generators of geometric models and computational meshes of Francis turbines runners

• Published in: Computer aided design Vol. 184; p. 103886
• Main Author: Bastl, Bohumír
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2025
• Subjects: B-spline surface; Geometric model; Isogeometric analysis; Multi-patch B-spline/NURBS meshes; NURBS surface; Water turbine; Isogeometric analysis; Water turbine; Multi-patch B-spline/NURBS meshes; Geometric model; NURBS surface; B-spline surface
• ISSN: 0010-4485
• DOI: 10.1016/j.cad.2025.103886

In this paper, we present a fully automatic approach to generate a geometric model of a Francis turbine runner wheel based on NURBS surfaces from given shape parameters and also a fully automatic approach to generate NURBS meshes of the inner parts of the runner wheel based on NURBS volumes. All the steps of the presented approaches are described in detail, including several challenges that need to be overcome, such as e.g. obtaining conformal parameterizations of streamsurfaces or automatic determination of suitable B-spline approximation curves for representing spatial blade profiles. NURBS meshes generated by the presented method are of good quality and can be used directly for numerical simulations of incompressible turbulent fluid flows based on isogeometric analysis, or, after simple conversion to hexahedral meshes, based on finite element method. The presented approaches can also be used in automatic shape optimization algorithms for Francis turbine runners based on gradient or gradient-free approaches. •The method constructs NURBS-based description of Francis turbine runner.•Streamsurfaces are obtained by solving 3D potential flow in the runner wheel domain.•Conformal parameterization of streamsurfaces is used for mapping to streamsurfaces.•NURBS-based volumetric model of inner parts of the turbine is also constructed.•NURBS-based volumetric model can be directly used in numerical simulations.