Optimisation of a pump-as-turbine runner using a 3D inverse design methodology

Abstract

In this paper the optimisation of a pump-as-turbine runner using a 3D inverse design methodology is presented. The baseline design is based on an existing runner designed with TURBOdesign1 by Zhu et al.[1, 2], that was then optimised by the genetic algorithm in Isight. In the work presented here the baseline design will be further optimised by minimizing secondary flow and profile loss factors while keeping the same meridional profile, stacking characteristics and work distribution in pump mode. The performance curves suggest that minimizing the secondary loss factor leads to an increase of the pump mode efficiency, whereas minimizing the profile loss coefficient benefits the turbine mode efficiency. These results strengthen the understanding of the trade-offs involved and provide guidelines for the design of runners for pump-as-turbine applications.