000126025 001__ 126025
000126025 005__ 20190812205232.0
000126025 020__ $$a978-85-60858-13-1
000126025 037__ $$aCONF
000126025 245__ $$aSurface Roughness Impact on Francis Turbine Performances and Prediction of Efficiency Step Up
000126025 260__ $$c2008$$bInternational Association For Hydraulic Research$$aFoz do Iguassu, Brazil
000126025 269__ $$a2008
000126025 300__ $$a10
000126025 336__ $$aConference Papers
000126025 520__ $$aIn the process of turbine modernizations, the investigation of the influences of water passage roughness on radial flow machine performance is crucial and validates the efficiency step up between reduced scale model and prototype. This study presents the specific losses per component of a Francis turbine, which are estimated by CFD simulation. Simulations are performed for different water passage surface roughness heights, which represents the equivalent sand grain roughness height. As a result, the boundary layer logarithmic velocity profile still exists for rough walls, but moves closer to the wall. Consequently, the wall friction depends not only on roughness height but also on its shape and distribution. The specific losses are determined by CFD numerical simulations for every component of the prototype, taking into account its own specific sand grain roughness height. The model efficiency step up between reduced scale model and prototype value is finally computed by the assessment of specific losses on prototype and by evaluating specific losses for a reduced scale model with smooth walls. Furthermore, surveys of rough walls of each component were performed during the geometry recovery on the prototype and comparisons are made with experimental data from the EPFL Laboratory for Hydraulic Machines reduced scale model measurements. This study underlines that if rough walls are considered, the CFD approach estimates well the local friction loss coefficient. It is clear that by considering sand grain roughness heights in CFD simulations, it forms a significant part of the global performance estimation. The availability of the efficiency field measurements provides a unique opportunity to assess the CFD method in view of a systematic approach for turbine modernization step up evaluation. Moreover, this paper states that CFD is a very promising tool for future evaluation of turbine performance transposition from the model scale to the prototype.
000126025 542__ $$fCC BY
000126025 6531_ $$aFrancis Turbine, Model & Prototype Testing, CFD Simulation, Efficiency Step Up
000126025 700__ $$g172125$$aMaruzewski, Pierre$$0243093
000126025 700__ $$g176678$$aHasmatuchi, Vlad$$0243100
000126025 700__ $$g105887$$aMombelli, Henri-Pascal$$0243096
000126025 700__ $$aBurggraeve, Danny
000126025 700__ $$aIosfin, Jacob
000126025 700__ $$aFinnegan, Peter
000126025 700__ $$g104417$$aAvellan, François$$0241012
000126025 7112_ $$dOctober 27-31, 2008$$cFoz do Iguassu, Brazil$$a24th IAHR Symposium on Hydraulic Machinery and Systems
000126025 7112_ $$dOctober 27-31, 2008$$cFoz do Iguassu, Brazil$$a24th Symposium on Hydraulic Machinery and Systems
000126025 773__ $$q1-10$$j1$$tProceedings of the 24th Symposium on Hydraulic Machinery and Systems
000126025 8564_ $$uhttps://infoscience.epfl.ch/record/126025/files/Surface%20Roughness%20Impact%20on%20Francis%20Turbine%20Performances%20and%20Prediction%20of%20Efficiency%20Step%20Up.pdf$$s836766
000126025 8564_ $$xpdfa$$uhttps://infoscience.epfl.ch/record/126025/files/Surface%20Roughness%20Impact%20on%20Francis%20Turbine%20Performances%20and%20Prediction%20of%20Efficiency%20Step%20Up.pdf?subformat=pdfa$$s2160503
000126025 8560_ $$femilie.reynaud@epfl.ch
000126025 909C0 $$xU10309$$pLMH$$0252135
000126025 909CO $$ooai:infoscience.tind.io:126025$$qGLOBAL_SET$$pconf$$pSTI
000126025 917Z8 $$x176678
000126025 937__ $$aEPFL-CONF-126025
000126025 973__ $$rREVIEWED$$aEPFL
000126025 980__ $$aCONF