22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-3.9.R1

EFFICIENCY OF EJECTOR DEVICES AND OF SOUNDABSORBING STRUCTURES FOR JET NOISE REDUCTION

V. M. Kouznetsov, A. G. Munin, A. F. Sobolev
Central Aerohydrodynamics Institute (TsAGI), Russia

Keywords: ejector devices, noise reduction, sound absorption

The experimental investigation results related to noise of model jets issuing from ejector noisesuppressing devices of rectangular and axisymmetrical shape and containing multielement nozzle and ejector are presented. The acoustical efficiency of noise-suppressing devices relative to axisymmetrical profiled nozzle with identical critical section areas and pressure ratios at the nozzles is determined. The results of theoretical and experimental research of high frequency noise reduction in the ejector duct with the use of soundabsorbing treatments are presented. The optimum treatment impedance dependency on aeroacoustical and geometrical parameters of the duct providing the most effective attenuation for the definite duct model is determined. Parameters of real structures, the impedance of which is the closest to the optimum values obtained on condition of the treatment impedance optimization are found. The experimental investigation data on noise reduction at the ejector exit due to locating multi-layered soundabsorbing structures in the duct are given. Comparison between the prediction and experimental investigation results is made.

view full paper