Author(s): C. Ozbey; Serhat Kucukali

Linked Author(s): Serhat Kucukali

Keywords: Angled fine screen; numerical modeling; porous media approach; flow field; turbulent kinetic energy

Abstract: The flow field as well as the turbulent quantities around the angled Oppermann fine screen, a specific type of physical barrier used at the water intakes of hydropower plants, were numerically analyzed in FLOW-3D under two different bar spacings of b=6 mm and b=10 mm, and horizontal angles of α=30° and α=45°. Darcy-Forchheimer porous media model coupled with the Large Eddy Simulation approach was applied in establishing the numerical model, and the results were compared with the experimental data for all bar spacing and angles that are under investigation. The comparisons were made considering the mean absolute percentage error between the physical and the numerical model results in accordance with the velocity and turbulent kinetic energy values. According to the simulation results, for all cases, the errors were lower than 10% which remains in the acceptable range. The so-called error values were significantly higher for the 45° angled Oppermann screen compared to the 30° angled case. Moreover, for both horizontal angles, the Oppermann screen having 10 mm bar spacing was found to yield higher prediction errors than the 6 mm bar spacing. Finally, the flow-straightening effect of the Oppermann fine screen was numerically shown to create a symmetrical and homogeneous downstream flow field.

DOI: https://doi.org/10.3929/ethz-b-000675921

Year: 2024