With the goal of broadening the operation range of hydraulic turbines, we propose a new-type hydraulic turbine in our research. The new turbine has no draft tube, but instead is equipped with a parallel diffuser and a volute, i.e. a radial vaneless diffuser and a spiral discharge collector, respectively. In this research, we carried out a CFD investigation on specific speed 77 [m-kW] prototype turbine to predict its performance. The simulation results showed that under large discharge there is a high risk of cavitation or pressure fluctuation. In this condition, the amplitudes of the pressure fluctuation are 0.6 percent and 1.3 percent of the effective head, on the volute wall and the parallel diffuser wall, respectively. The possibility of flow instabilities such as a vortex rope precession and a rotating stall to occur is small enough to keep operating the turbine at both deep part-load and full load. The final design of the turbine has been decided based on this investigation. The turbine verification tests are going to start in early 2021.
|ジャーナル||IOP Conference Series: Earth and Environmental Science|
|出版ステータス||Published - 2021 6月 15|
|イベント||30th IAHR Symposium on Hydraulic Machinery and Systems, IAHR 2020 - Lausanne, Virtual, Switzerland|
継続期間: 2021 3月 21 → 2021 3月 26
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