Author(s): Guillaume Bon; Ludovic Chatellier; Yves Le Guer; Cecile Bellot; Xavier Casiot; Nassim Razaaly; Laurent David

Linked Author(s): Laurent David

Keywords: Trash-rack; Head loss; CFD simulations; Optimization; Fish guidance intake structure; Fluid mechanics

Abstract: Ecological continuity in rivers has become a major concern for low-head hydroelectric power plants. The implementation of new fish protection systems and particularly the updated recommendations regarding inclined trash-racks with small bar spacing, present new challenges. The bar profile of the trash-rack is crucial for reducing head losses and preventing clogging issues. This paper presents the findings of the optimization of an inclined trash-rack bar design for hydroelectric power plant water intakes. It consists in minimizing the head loss coefficient and drag force coefficient of bars while considering dimensioning and feasibility constraints. A parameterized profile is defined to ensure feasible bar shapes in large volumes. The head loss and drag coefficient are calculated using 2D CFD simulations and a genetic algorithm is used to perform a global optimization. In previous bar shape studies, researcher primarily focused on some profiles with low head losses and with specific circular spacers. However, bar shapes must be adapted for different types of spacers, especially with circular and comb spacers. The inclination angle of the trash-rack is also an important parameter to consider when looking for a suitable bar profile. This work aims to address to the adaptation of profiles based on new recommendations for trash-rack inclination and new techniques for maintaining bar spacings. New profiles with minimal head losses have been found for specific trash-rack configurations.

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

Year: 2024