Numerical analysis of an initial design of a counter-rotating pump-turbine

Abstract Renewable sources of energy are on the rise and will continue to increase coming decades [1]. A common problem with renewable is that they rely effects which cannot be controlled, for instance strength wind or intensity sunlight. The ALPHEUS Horizon 2020 EU project has aim develop a low-head hydraulic pump-turbine can work as grid stabilising unit. This presents numerical results an initial hub-driven counter-rotating design within ALPHEUS. Computational fluid dynamics simulations carried out in both prototype model scale, pump turbine modes, under steady-state unsteady conditions. indicate have efficiency roughly 90 % modes wide range operating reveal complex flow pattern downstream two runners frequency analysis show dominating pressure pulsations originates from rotor dynamics. Given promising high efficiency, this makes ideal platform optimise transient operations further.