R. Taghavi, G. Raman

A parametric experimental study of a multi-jet rectangular ejector was conducted. The jets emerged from four converging rectangular nozzles into a straight, adjustable area rectangular ejector. The fully expanded primary jet Mach numbers studied were 1.2, 1.4 and 1.6 at area ratios (ejector area/primary area) of 7, 12 and 17. A pitot tube was used to survey the flowfield at the exit of the ejector. In addition, pressure sensitive paint (PSP) was used for mapping the static pressure distribution on the ejector wall. The flow measurements indicated that for all Mach numbers studied, increasing the area ratio from 7 to 12 improved the mixing between primary and secondary streams. A further increase in the area ratio from 12 to 17 did not produce a proportional increase in the mixing. The acoustic measurements indicated that the frequency of the. screech tone decreased with the addition of the ejector shroud. In addition, the screech frequency decreased with a decrease in the area ratio. The static pressure distribution on the ejector wall (both pressure sensitive paint and measured pressures) indicated that when the area ratio was increased from 7 to 12, the pressures relaxed to ambient levels upstream of the ejector exit A further increase in the area ratio did not provide any further benefits. It appears from our data that there is the potential to shorten ejector length for certain Mach number and area ratio combinations.

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 9 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.113-121; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics, noise measurement

Bibliothek

1995