P.H. Bent, D.K. McLaughlin, D.E. Thomson

An experimental investigation has been made to determine the influence of discharge configuration on the aerodynamic sources of broadband noise in centrifugal turbomachinery. By applying a variety of discharge configurations to a single centrifugal impeller and performing detailed measurements of the fluid dynamics and radiated noise, it has been possible to identify two distinct noise generation mechanisms. The first, and often the strongest, is the interaction of the impeller with a highly coherent, rotating discharge flow instability (i.e. of the character of rotating stall). The second noise source is trailing edge scattering resulting from the interaction of the impeller blade trailing edges with the turbulence convecting in the impeller discharge. For both of these sources, it was found that at certain frequencies the interactions on several impeller blades were in phase. This in tum leads to significantly higher levels of radiated noise at those frequencies. The character of the rotating discharge instability, and consequently the noise generated by this phenomenon, was found to be extremely sensitive to the discharge geometry. The trailing edge scattering, however, was found to be relatively insensitive to changes in the discharge configuration.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.607-614; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1992