Dynamic stress analysis of a large capacity Pelton turbine runner

Abstract The dynamic stress characteristics of a Pelton turbine runner is an important index to evaluate the stability of unit. Aiming to analyse the dynamic stress of a large capacity prototype Pelton turbine runner influenced by the unsteady impact load of a high-speed jet, the unsteady flow simulation was firstly taken for the Pelton turbine runner to conclude the hydraulic model of internal flow and the performance parameters. Then, the dynamic stress of the Pelton runner was solved by fluid-structure coupling numerical method. The dynamic stress variation trend of several monitor points distributed on the splitter, brim, bucket root was analysed. It is concluded that the impact load of the jet could lead to the significant change in the dynamic stress on specific location of the bucket surface, and the stress concentration was found at the bucket root.