On the correlation between runner blade dynamic stresses and pressure fluctuations in a prototype Francis turbine

Abstract Francis turbines operating in off-design conditions are subject to pressure fluctuations resulting from the development of hydrodynamic instabilities draft tube. Depending on nature flow-induced (synchronous or convective), this may induce dynamic stresses runner blades, increasing fatigue and risk crack propagation. This paper proposes identify impact tube flow turbine runners. Measurements conducted a prototype Hydro-Québec low-load full-load, including strain measurements stationary rotating components, respectively. It is first noted that convective component part-load vortex main source excitation for blades. The amplitude corresponding however reduced at locations closer leading edge, which dominant result propagation synchronous fluctuations. Finally, correlations between measured water passages tentatively established observed both deep conditions. aims evaluate feasibility estimating blade based signals components further investigation.