Numerical Analysis of a Model Pump-turbine Internal Flow Behavior in Pump Hump District

Abstract

The hump region of head-discharge characteristic curve has great influence on the operation stability of pump-turbine. Therefore, it is significant to conduct deep research on the flow characteristic in the hump district of pump mode. Detailed study of the internal flow in hump district has been made combined with model experiments in this paper. Research discussed the adaptability of different turbulent model toward calculation in pump mode conditions and carried on three-dimensional numerical simulation of the whole pump-turbine flow passage. Then the head, efficiency and power characteristic curves of different pump modes were analysed. The numerical simulation results are in good agreement with experimental data. Comparing flow field both in hump district and of optimal operating point, it is found that the formation of hump area is concerned with complex flow in the runner and guide vanes domains, such as secondary flow, backflow and vortex patterns. The study aims to explore the cause for hump district generating of pump-turbine and its internal flow mechanism.