Experiences with the hydraulic design of the high specific speed Francis turbine

27th IAHR Symposium on Hydraulic Machinery and Systems

Obrovsky, J.^1 ; Zouhar, J.^1

Hydraulic Engineer, R and D Department, KD Blansko Engineering, a.s., apkova 2357/5, Blansko

678 01, Czech Republic^1

关键词: Cavitation characteristics;    Cavitation conditions;    Design process;    High specific speed;    Hydraulic designs;    Hydropower plants;    Optimization algorithms;    Simplex optimization;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/1/012027/pdf
DOI  :  10.1088/1755-1315/22/1/012027

来源: IOP

【 摘 要 】

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of KD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between n s=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.