CFD-based rehabilitation for the high specific speed Francis turbine. Issue 2 (March 2019)

• Record Type: Journal Article
• Authors: Kubo, K; Nakashima, T; Shima, R; Enomoto, Y
• Is Part Of: IOP conference series. Volume 240:Issue 2(2019)
• Publication Date: 2019-03
• Subjects: Earth sciences -- Periodicals; Environmental sciences -- Congresses; Environmental sciences -- Periodicals; 550.5
• DOI: 10.1088/1755-1315/240/2/022054
• Languages: English
• ISSNs: 1755-1307

Abstract

Abstract: This paper present about the CFD based rehabilitation project for high specific speed (over 300 m-kW) Francis turbine. The area of rehabilitation was Spiral casing, Stay vane, Guide vane, Runner, and restricted Draft tube (draft elbow). The main goal of this project was to increase the turbine efficiency at all operating range with high operational stability, low noise as well as high cavitation performance. On the development phase of this project was carried out with CFD only (without Model test) to reduce the time of development. On the first step of this project, the shape of all components was optimized to reduce the hydraulic loss and to increase the cavitation performance with steady state CFD. After that, the operational stabilities (ex. Pressure fluctuation) on the partial load and over load point were verified with unsteady CFD. Finally, the field tests were carried out to confirm the performance of new turbine. It was found that the new turbine has excellent performance in efficiency, power output and operational stability (vibration and noise) compared with existing turbine.