Upgrading existing hydropower plants into pump storage using pump-turbines is an economical approach to increasing energy storage capacity. Installing an additional pump at the pump-turbine outlet can improve cavitation performance and reduce submergence requirements. The present work proposes a methodology for designing an axial flow pump for such retrofitting applications. A classical method available in the literature was used for establishing the global parameters and boundary conditions of the pump design. The method was automated using a Python 3.13 script to handle a wide range of design parameters. The design output was verified with five different cases covering a wide operational range, from low to high specific speed axial pumps. The results met the required performance criteria, with deviations in head prediction ranging from 0.28 to 1.70 m for most cases. The estimated maximum error was 20% for the mid-range of specific speeds, and the largest deviations were observed for the extreme design conditions. These deviations under extreme specific speeds can be attributed to the limitation of the underlying empirical correlations, which are primarily developed for a typical axial pump. Therefore, further refinement or robust optimization is necessary for reliable application under such extreme conditions. Overall, the verification clearly demonstrated the potential to produce geometrically consistent and hydraulically reasonable designs. The adapted design approach provides good confidence and will provide baseline designs for the booster pump in retrofitted hydropower plants.
Bijukchhe et al. (2026) studied this question.