Unsteady CFD analyses with ANSYS CFX to investigate the possibility of vortex shedding at the guide vanes.

The trailing edge used on the guide vanes designed to prevent vortex shedding, and the analysis showed no sign of shedding. Therefore, the engineers concluded that the problem was not caused by vortex shedding at the guide vanes.

SELF-EXCITED VIBRATIONS AND RESONANCE:

To determine the cause of vibration, The engineer’s team began by examining the possibility of resonance effects or self-excited vibrations of a guide vane that would occur at a natural frequency. They used a finite element model to calculate the first four mode shapes using undamped modal analysis. Engineers found that there were no natural frequencies close to the observed vibrational frequencies.