Analysis and reduction of the pressure and shear damage probability of fish in a Francis turbine

• Published in: Renewable energy 2022-11, Vol.199, p.462-473
• Main Authors: Zhu, Guojun, Guo, Yuxing, Feng, Jianjun, Gao, Luhan, Wu, Guangkuan, Luo, Xingqi
• Format: Article
• Language: English
• Subjects: Damage probability; Fish-friendly; Francis turbine; Runner optimization
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2022.08.158

The fish mortality rate for a Francis turbine mainly depends on the runner. To reduce fish injury and mortality caused by Francis runners, the effects of the number and wrap angle of runner blade on the pressure and shear damage probability are investigated in this paper. The pressure and shear damage probability of different runner schemes are evaluated quantitatively by the computational fluid dynamics (CFD) simulation, and the accuracy of CFD simulation has been verified. The results show that both the pressure and shear damage probability induced by runner have a positive correlation with the discharge. But the shear damage probability is much less than the pressure damage probability. Pressure damage probability should be the main factor to be considered in the design of fish-friendly Francis runner. Reducing the blade number and increasing the warp angle of the runner blade could effectively reduce the damage probability caused by low pressure and high shear stress. But it has little effect on the damage probability caused by high pressure change rate and also results in slight decrease in hydraulic efficiency. This work is beneficial to the fish-friendly turbine design and optimization.