T.G. Tillmann, W.P. Patrick

This paper describes the results of an experimental study of a supersonic mixer ejector in forward flight. Mixer ejectors are a candidate means to mix out the high-velocity core engine exhaust on the High Speed Civil Transport (HSCT) aircraft, thereby reducing jet noise at takeoff and landing. The mixer ejector concept involves the introduction of largescale, low-loss streamwise vortices into the ejector mixing duct. These vortices entrain large amounts of secondary fluid and rapidly stir it into the primary stream. This results in increased ejector pumping performance, and more completely mixed flows exiting the ejector shroud. Previous investigations of mixer ejectors show that at static and low-speed forward flight conditions, pumping benefits on the order of 100% were achieved relative to conventional ejector designs. The goal of the present study was to document the mixing performance of a two-dimensional, supersonic mixer ejector in the presence of high speed forward flight. The experiment was performed over the range of forward flight Mach numbers from 0.3 to 0.5, a primary total temperature of 1000°F, and a primary jet exit Mach number of 1.5. Detailed flowfield surveys of total temperature, total pressure, and static pressure were performed to characterize the mixing. Laser-Doppler Velocimetry (LDV) measurements of the mixer ejector exit plane three-dimensional velocity field were performed in or- · der to quantify the vortical flows responsible for enhanced mixing. A principal finding of this study is that the mixer ejector axial vorticity mixing benefit exists for increased forward flight Mach numbers. In addition, local regions of high axial velocity were identified at the mixer ejector exit plane. These regions could represent a significant jet noise source.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 9 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.854-862; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1992