STUDY OF CORRELATION BETWEEN CAVITATION AND SEDIMENT EROSION IN FRANCIS TURBINE

Abstract

Cavitation in reaction turbines is undesirable and more vulnerable, presenting challenges such as vibration, performance degradation, and damage to hydraulic turbine components in hydropower plants. In Nepal, the Himalayan Rivers generate substantial sediment with hard abrasive particles, posing a hindrance to the economic development of hydropower resources. The current study employs numerical analysis to investigate the effects of cavitation and sediment, as well as the correlation between these two factors in a Francis turbine. The SST k-omega turbulence model is utilized to address fluid turbulence phenomena, and computational fluid dynamics (CFD) techniques are applied through ANSYS-Fluent software to explore the performance characteristics related to sediment and cavitation erosion in a hydraulic Francis turbine. For erosion rate calculations, the Tabakoff–Grant particle trajectory erosion model is employed. The study predicts cavitation characteristics using the Schnerr and Sauer cavitation model for interphase mass transfer. Furthermore, the Multi-phase Dense Discrete Phase model is chosen to examine the combined impact of cavitation and sediment erosion in ANSYS-Fluent. The study investigates three distinct operating conditions under the effects of cavitation and sediment erosion, namely part load, Best Efficiency Point (BEP), and