Effect of Boundary Conditions on Fluid–Structure Coupled Modal Analysis of Runners

To predict the resonance characteristics of hydraulic machinery, it is necessary to accurately calculate natural modes runners in operating environment. However, existing research, boundary conditions numerical modal analysis runner were not unified. In this paper, a prototype Francis pump turbine was carried out using acoustic–structure coupling method. The results three different constraints compared. influence energy loss on chamber wall studied by absorption boundary. show that constraint condition (especially rotating shaft) has significant impacts torsional mode, radial 1 nodal-diameter and 0 nodal-circle maximum differences frequencies under are 69.3%, 56.4%, 35.1%, 9.4%, respectively. change closely related shapes. On other hand, mainly affects modes, negligible. can provide references for design machinery runners.