Investigation of aeration performance of Ilısu Dam outlet using two-phase flow model

Abstract

Cavitational damage is very important for huge hydraulic structures exposed to high flow velocities. The most effective solution to avoid this damage is to mix air into the flow through an aerator device. The conventional method which is the physical model test is not sufficient to determine the air entrainment owing to scale effects caused by viscous forces. Computational fluid dynamic (CFD) method can allow simulating and analyzing the structures with real prototype dimensions by eliminating these scale effects. In this study, an outlet tunnel together with its aeration tunnels having 12 m diameter transformed from three derivation tunnels of a huge dam was analyzed using three-dimensional CFD model in real three dimensions. The scaled physical model results were also used to see the scale effects and to test validation of the numerical results. The aerodynamics of the aeration gallery and aeration tunnel were analyzed by two-phase (air–water) turbulent model, and the aeration performance of the system was tried to be improve with the help of CFD results. Three different designs for the aeration were analyzed and it was seen that the enhanced designs significantly increased the aeration performance of the system.