Hydraulic performance of siphonic turbine in low head sites

This paper investigates the performance of a siphonic turbine considered to be installed in Grevelingen Brouwersdam in the Netherlands. Based on available experimental results on air-water ow in downward sloping pipes, a one-dimensional numerical hydrodynamic model is developed to nd optimised combinations of air and water ow rates. The generated power of an air turbine, connected to the siphon, is calculated and the efficiency is determined for several hydraulic and geometrical conditions. A maximum efficiency of 7.2% is observed, which is way below the estimated values in previous studies. The total generated power is about 4 MW for a total water discharge of 4500 m3/s and an available head of 1.25 m. This relatively low performance has to be kept in mind when identifying the best available technology for low head sites.