Author(s): Adriano Oliveira; Irene Fernandes; Maria Teresa Viseu; Marco Zorn; Stefan Riedelbauch
Linked Author(s): Stefan Riedelbauch
Keywords: No Keywords
Abstract: The Alqueva dam has created one of the largest artificial lakes in Europe on the Guadiana River in southern Portugal. The Alqueva II Pump Storage Power Plant (PSPP) began operating in 2012 and is equipped with two reversible pump-turbines (PT1 and PT2), each one with a nominal turbine flow of 200 m3s-1. The outlet structure diverges symmetrically across two draft tubes and four tailrace channels per power unit, all of them equipped with trash racks (14x4.25 m2 cross section each) at the tailwater reservoir connection. In the project design, the overall dimensions of the outlet structure and trash racks were defined based on the flow rate, to allow maximum performance and operational efficiency. Design validation was conducted using a scale physical model where several analyses were performed focusing on the flow velocities along the outlet structure. More recently, in the scope of the XFLEX Hydro project, both computational fluid dynamics (CFD) simulations and prototype tests were performed in collaboration with the University of Stuttgart, further complementing our overall knowledge regarding the prior results. This abstract presents a comparative analysis of flow behaviour and mean velocities obtained at the trash racks section of the outlet structure through physical and numerical models, as well as within prototype tests, considering different inlet conditions in turbine mode, as well as distinct tailwater reservoir levels.
Year: 2024