Analysis Of Fluid-Structure Interaction On Runner Blades Of A Low Head Francis Turbine

In the turbine blades hydraulic performance optimization process,mechanical properties of small low head Francis hydraulic turbine blades are developed by using CFD technology,designers often based on the project experience estimation and ignored the analysis on the special,or understanding of the importance of lag.This makes in recent years,used CFD technology development the new efficient turbine runner is put into operation,high proportion of crack,long term running on non-optimal conditions of the turbine runner blades even breaking or broken.Therefore,based on CFD technology to optimize the new runner on the hydraulic design,mechanical analysis of the the turbine blades have become necessary.In this paper,based on the_***hydropower station turbine generator unit uprating project,using CFD technology development the hydraulic turbine blades,static and dynamic characteristics analysis of the turbine blades conbine with considering FSI.The main work are as follows:（1）According to established components of turbine parameters,the whole flow passage water model and structure model are established by UG,for each components of the grid discretization by grid generation software.（2）Based on the FLUENT software,using RNG k-εturbulence model and SIMPLE algorithm,numerical simulation of the minimum head,rated head,maximum head,guide vane opening from 17o³3oat operating conditions,the turbine internal three-dimensional steady flow.（3）Based on the ANSYS software,using FSI method,subjected to different loading mode and the development condition,static analysis of turbine blades.（4）Based on the ANSYS software,using APDL language,numerical calculation the dry modal and wet modal of turbine runner and single blade,and combined with several units of characteristic frequency analysis of the possibility of resonance in operating conditions of turbine blades.At the same time,influence on dry modal and wet modal of the turbine runner in different loads,different units speed and different fluid domain density are discussed.Through the above work,the evaluation system of the static and dynamic characteristics of the turbine blades.The results showed that:under all the left side of the output restrictions line operating conditions,the turbine blades static strength can meet the requirement,Carmen vortex at the outlet of the runner blades is not easy to induce turbine vibration.In non-optimal operating conditions,outlet of guide vanes due to off flow caused by water pressure fluctuation is easy to induced to turbine vibration.At the same time,the numerical calculation in the paper can also be used as the same type of turbine blade structure analysis of mechanical properties,especially suitable for practical engineering projects.