Author(s): Ozbey; Serhat Kucukali
Linked Author(s): Serhat Kucukali
Keywords: No Keywords
Abstract: High head losses at fine screens built for fish protection at hydropower plants lead to energy and revenue loss. We addressed this operational problem by investigating the hydrodynamics characteristics of a streamlined Oppermann bar profile. Accordingly, two types of physical barriers used at the water intakes of hydropower plants, the Oppermann and the rectangular fine screen, each having the same bar spacing of 10 mm, were numerically compared by the head losses. The flow through both screens was simulated in FLOW-3D under identical initial and boundary conditions, and the up-and downstream water surface profiles were analyzed to evaluate the head losses. Simulations were performed under three different turbulence models, namely the standard k-ε, k-ω, and the Large Eddy Simulation (LES). The numerical results revealed that the head loss generated by the Oppermann fine screen was 21.5% less than the rectangular fine screen. This head loss difference was attributed to the fact that the recirculation zone area is reduced by almost 90% behind the Oppermann profile due to the streamlined bar shape. Among the tested turbulence models, different from the existing studies, it was numerically shown that the triangular shape of the recirculation zone was only captured by the LES model for very fine mesh indicating the importance of mesh resolution.
Year: 2024