Numerical investigation of the interaction between jet and bucket in a Pelton turbine

This article presents the numerical investigation of the interaction between the jet and the bucket in a Pelton turbine. Unsteady numerical analyses were carried out on a single jet Pelton turbine installed in the north of Italy. A two-phase inhomogeneous model was used. Two different jet configurations were analysed and compared. In the first configuration, the interaction between the runner and an axial-symmetric jet characterized by a given velocity jet profile was investigated, whereas in the second configuration the runner was coupled with the needle nozzle and the final part of the penstock and the interaction between the jet and the bucket was analysed. A detailed analysis of the torque highlighted the influence of the shape of the water jet on the turbine losses and the influence of the stator on the efficiency of this type of hydraulic machines was shown. The numerical results were compared with the experimental data derived from the installation test of the turbine in order to validate the numerical analysis.