98. CFD-based Runner Design for the Dobsina Storage Pump

For the two storage pumps in the hydro power plant Dobsina, VA TECH HYDRO designed new impellers and diffuser vanes. After the thorough numerical analysis of the existing machine new impellers and diffuser vanes were designed with the objective of improving leading edge cavitation in the impeller of the first stage as well as the overall efficiency of the complete machine. According to the project schedule VA TECH HYDRO proposed an impeller design which was created with the help of coupled CFD calculations with improved cavitation behaviour and higher efficiency. The hydraulic design served as the basis for the manufacturing of the prototype without further model testing. The first double-flow group was commissioned in late 2002 and the second group came into operation ahead of the project schedule in the early summer of 2003. Currently both groups operate to the customer's full satisfaction. In 1997 the two Francis turbines in the Dobsina plant were refurbished by VA TECH HYDRO and operate trouble-free and to the customer's full satisfaction.