Numerical investigation for intake and discharge conditions of horizontal multi-jet Pelton turbines

Abstract Modernization of existing Pelton turbines comes with a required increase in power and efficiency. At the same time, maintainability and accessibility should be improved. Here a replacement of the existing units with horizontal multi-jet turbines can achieve these requirements. Concurrently, the hydraulic inlet and outlet conditions are challenging as the penstock and tailwater are often reused. At two examples, one in operation, one in construction, the possibilities to design and improve the inflow and discharge situation with the aid of numerical methods is shown. Efficiency and flow conditions can be significantly improved when the turbine in- and outlet is designed for the specific on-site situation.