Seeing that hydraulic turbines have been well developed and widely used in generation system with capacities up to 1 GW per unit [21,22], at the end of the loop circuit, a hydraulic turbine is driven by the pressurized seawater from the pump, through which the high water energy is transformed into mechanical rotational energy. Finally, the electric generator connected to hydraulic tur- bine is driven. In the existing hydraulic turbines, the Pelton turbine is the most suitable for high pressure and velocity jets, for its oper- ating pressure range is from 5 to 185 bars.
In this turbine, the hydraulic potential energy is converted into hydraulic kinetic energy by a set of fixed nozzles. When the high speed water jets from nozzles hit the buckets placed around the turbine runner, mechanical torque is produced at the turbine shaft. The diagram of the Pelton turbine is shown in Fig. 5.
As a nozzle model is developed, the velocity of the water at the nozzle is derived by Bernoulli equation