Simulation of unsteady flow in a Francis turbine draft tube

摘要

If the performance of a runner and draft tube can be predicted at the design stage, savings can be made in both time and money. In the study described here, the unsteady flow field in the draft tube of a Francis turbine is numerically simulated for part load conditions. The runner and draft tube are coupled in the calculation. The results successfully represent the eccentric spiral vortex swirling in the draft tube and the induced pressure oscillations.