Research On Structural Analysis Of Francis Hydro Turbine Runner

Hydraulic turbine runner is core part of energy conversion for hydro-power unit, and its structural and mechanical property will directly affect safety, reliability, economic operation for hydro-power unit. The research of structural and mechanical properties including the rigidity strength and modal analysis ,is the key part of digital design for hydraulic turbine. As Hydro turbine blade is a very complex body closed by sculptured surfaces and the operating condition of the runner is also very complicated, traditional research way was combined the simplified theoretical analysis and model test. Hydroelectric units are becoming larger and larger in size, it make a great challenge of structural design and analysis for hydraulic turbine, With the development of numerical simulation technique and computer science in recent decades, hydro-power equipments industry is trying to explore that the simulation technique of structural analysis based on FEM is how to be applied in optimization the design of runner structure and upgrade the reliability of design.Taken the runner of a Francis turbine as the research object, this dissertation study the mechanical and mathematical model, mechanical analysis, boundary condition and simplified loads of computational force based on the operationconditions of Francis turbine. On the basis of hydraulic design and numerical simulation of flow field for runner of rehabilitation scheme, 3D geometry of Francis runner was constructed. Research on structural analysis of the Francis hydro turbine runner is carried out with ANSYS software. In consideration of structural features and operation conditions, FEM model of the runner is presented using 10-node tetrahedral structural solid element in the process of structural analysis. Centrifugal force, gravity and water pressure which was obtained from the inside flow simulation are considered in the calculation model. As water pressure distribution is related to Fluid-structure Interaction, sequence couple method is adapted in computation. The water pressure distribution on the runner was calculated with FLUENT software and loaded on the finite element model by the APDL .A static analysis and modal analysis for the runner have been done with ANSYS software, in which modal analysis is respectively analyzed in both water and air. The analysis result proves the correctness of design of the hydro turbine's runner, and also offers the theoretical basis and suggestions for the practical engineering application and safe operation of the hydro-power unit.It shown that not only reduce the cost and the cycle of the runner design, but also can optimize structural design with applying Structural analysis simulation technique, which is significant both in theoretical and actual engineering.