Numerical study of cavitation characteristics in mixed-flow turbine

Abstract In this paper, a numerical method is employed to investigate the internal flow of a mixed-flow turbine. A fully three-dimensional turbulence calculation method is adopted, utilizing the RNG k-ε turbulence model and SIMPLE algorithm. This simulation calculates the entire flow channel from the volute inlet to the draft tube outlet in a single comprehensive simulation. Based on the obtained three-dimensional cavitation flow field data, a flow field analysis of the runner’s internal flow is conducted, allowing for the computation of the critical cavitation coefficient. Additionally, the cavitation conditions at the runner outlet and within the draft tube under different cavitation characteristics are simulated.