2014 Volume 80 Issue 809 Pages FE0007
The Rotating instability, abbreviated to RI, in a centrifugal blower with shrouded impeller is investigated by experiments and CFD analyses. The RI occurs in a partial-flow operation of the blower prior to stall with mild fluctuations of impeller-discharge velocity and radiated noise, and appears in the power spectra as a gradual hump at almost half of the blade-passing frequency. The cause of the RI is supposed to be unsteady vortices rotating along the impeller periphery and the irregular change of the vortex rotating speed may generate the gradual hump in the power spectra. The RI noise is generated by the impingement of the impeller-discharge flow with unsteady vortices. Fundamental characteristic and structure of the unsteady vortices are investigated supplementary by detailed measurements using a double-phase-locked averaging method and also CFD analyses.
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A