Flow induced noise characterization of pump turbine in continuous and intermittent load rejection processes. (August 2019) - Mao, Xiuli
Abstract: In order to study pump turbine stability in view of flow induced noise, this paper focuses on two-part operation of one high head reversible turbine: transient load rejection process and intermittent vane closing conditions. Both above simulations are solved by DES turbulent model, additionally, the flow field results are regarded as sound source and analyzed comparatively by LMS software. Except for flow field interpretation, some developing rules of flow induced noise during the period of pump turbine load rejection are found. The result indicates that flow induced noise radiation is consistent with internal fluid characteristics, and the developing trends are similar which acquired from these two part calculations, whereas the values are distinct. This work provides a reference for the study of pump turbine operating stability from the acoustic aspect, and for pump turbine design work as well. Highlights: Transient results show that rotor-rotor interaction influence on flow field is stronger than that of rotor-stator interaction during the continuous load rejection period. The flow induced noise radiation is consistent with fluid characteristics during the period of pump turbine load rejection. Its radiation level is determined by the pressure fluctuating frequency and shell natural frequency. The shape of sound distribution likes ∞ and sound level in different directions and faces are symmetrical. PSD at homologous locations of transient load rejection is with one more magnitude than that of fixed vane conditions. Both fixed vane calculations and continuous vane closure obtained similar flow induced noise developing tendency, even the acoustic pressure levels are different.