Simulació de la cavitació en un rodet de turbina Francis per diferents condicions d'operació.

Abstract

Clean energy development is vital for combating climate change and limiting its most devastating effects. Th erefore, this thesis presents the study and analysis of the performance of a hydraulic turbine that provides clean electric energy. The turbine it has been studied is the GAMM Francis turbine . Using Ansys® CFX, the Francis turbine is analysed working at di fferent operating conditions. A uniform incoming flow is simulated through the runner blades for different values of discharge and head . Then, t he static pressure at the draft tube outlet boundary condition is gradually decreased until the vapour pressure is reached inside the runner . Thus, the cavitation phenomenon that come up on the blade is studied while keeping the remaining parameters unchanged. To study the influence of the distributor, and benefiting of its axisymmetry , a slice of the 3D fluid domai n is made using SolidWorks® . Then, the 3D fluid simulation is performed for different opening angles of the guide vanes to see how this affects the fluid’s velocity profile . Finally, an analysis of the flow at the outlet of the distributor is carried out t o compare if using a uniform incoming flow at the inlet of the runner provides results realistic enough, according to the experimental data