Author(s): A. Aghakouchak; N. Nasrollahi; D. Schlabing; J. Tuhtan; M. R. Kavianpour
Linked Author(s): Jeffrey Tuhtan
Keywords: Erator; Air-water flow; Cavitation
Abstract: The flow downstream of hydropower plant outlet gates is frequently subjected to cavitation due to high flow velocity and low pressure. The most effective method in preventing cavitation is through the use of flow aeration just after the gates, where the risk of cavitation is the highest. Several previous experimental and numerical studies have been done on air-water flow downstream of the gates to quantify the air demand needed to prevent cavitation. However, due to the complexity of the flow system and the number of effective parameters that effect flow aeration, still a general relationship to quantify the air demand has not been found. In this study, the experimental analyses of gated outlet tunnels for 7 different dams are used to develop a fuzzy base rule system, optimized by Simulated Annealing (SA) method, to predict the air demand downstream of the outlet gates. A numerical model, calibrated with the experimental data, was used to investigate the aerator size and the critical gate opening. Moreover, a new method to predict the air demand downstream of the outlet gates based on the experimental data is proposed. It is hoped that the results of this study can be used by the designers of hydraulic structures.
Year: 2007