000255262 001__ 255262
000255262 005__ 20190812210021.0
000255262 037__ $$aCONF
000255262 245__ $$aModal Response of Hydraulic Turbine Runners
000255262 260__ $$c2006$$bInternational Association For Hydraulic Research
000255262 269__ $$a2006
000255262 300__ $$a9
000255262 336__ $$aConference Papers
000255262 490__ $$aVibration, noise, and pressure surge$$vF264
000255262 520__ $$aThe mechanical design of hydraulic turbines is conditioned by the dynamic response of the runner that is usually estimated by a computational model. Nevertheless, the runner has complex boundary conditions that are difficult to include in the computational model. One of these boundary conditions is the water in which the runner is submerged. The effect of the added mass and damping of water can modify considerably the natural frequencies of the runner. In order to analyze this effect on a Francis turbine runner, an experimental and a numerical investigation in a reduced scale model was carried out. The experimental investigations was based on modal analysis. Several impact tests with the runner in air and in water were done. The response was measured with accelerometers located in different positions of the runner. Special attention was taken to determine the most suitable positions of measurements and impacts. From the modal analysis, the natural frequencies, damping ratios, and mode shapes were determined. The simulation of the same runner was also carried out using a FEM method. First, some tests including a sensitivity analysis wee done to check the accuracy of the numerical results. Second, the runner was simulated and the frequencies and mode shapes were calculated both in air and in water like in the experiment. The simulation was compared with the experimental results to determine its accuracy especially regarding the added mass effects. Similar mode shapes and frequency reduction ratios were obtained so the simulation gave rather good results. In the paper, the frequencies, damping and mode shapes obtained in air and in water both from experiment and simulation are indicated. The same mode shapes obtained in air were obtained in water bit with lower natural frequencies and higher damping ratios. The difference in the natural frequencies is shown to be dependent basically on the added mass effect of the water and not on its added damping. This difference also depends on the geometry of the mode presenting different values for different mode shapes. Using non-dimensional values, the reduction in the natural frequencies can be extrapolated to other Francis runners presenting similar geometrical characteristics.
000255262 542__ $$fCC BY
000255262 700__ $$aLiang, Q.W.
000255262 700__ $$aRodriguez, C.G.
000255262 700__ $$aEgusquiza, E.
000255262 700__ $$aEscaler, X.
000255262 700__ $$aAvellan, François$$0241012$$g104417
000255262 7112_ $$dOctober 17- 21, 2006$$cYokohama, Japan$$a23rd IAHR Symposium on Hydraulic Machinery and Systems
000255262 773__ $$q1-9$$j1$$tProceedings of the 23rd IAHR Symposium on Hydraulic Machinery and Systems, Yokohama, Japan
000255262 8560_ $$femilie.reynaud@epfl.ch
000255262 8564_ $$uhttps://infoscience.epfl.ch/record/255262/files/Modal%20Response%20of%20Hydraulic%20Turbine%20Runners.pdf$$s1022883
000255262 8564_ $$xpdfa$$uhttps://infoscience.epfl.ch/record/255262/files/Modal%20Response%20of%20Hydraulic%20Turbine%20Runners.pdf?subformat=pdfa$$s1888179
000255262 909C0 $$xU10309$$pLMH$$mfrancois.avellan@epfl.ch$$0252135
000255262 909CO $$qGLOBAL_SET$$pconf$$pSTI$$ooai:infoscience.epfl.ch:255262
000255262 960__ $$aemilie.reynaud@epfl.ch
000255262 961__ $$alaurence.gauvin@epfl.ch
000255262 973__ $$aEPFL$$rREVIEWED
000255262 980__ $$aCONF
000255262 981__ $$aoverwrite