Experimental study of the sound reduction for the side air-intake of a helicopter turboshaft engine

  • S.-A. Meslioui Aiolos Eng. Corp., Toronto, Ont., Canada
Keywords: helicopters, noise abatement, helicopter, lining, noise reduction, inlet, turboshaft engine, blade passing frequency, feltmetal material, honeycomb, total power, BPF tone, sound reduction, side air-intake, solid backplate, acoustic treatment, compressor

Abstract

Helicopters are of considerable interest for short haul flights especially between airports and downtown. However, the high sound levels involved represent one of the main obstacles to the development of this very promising market. The paper deals with the use of a lining for reducing the noise radiated by the inlet of a turboshaft engine at the blade passing frequency of the compressor (8 to 10 Hz). The inlet is perpendicular to the shaft axis. The used liners consists of a solid backplate and a layer of feltmetal material separated by an internal partition in the form of a honeycomb. The efficiency of the acoustic treatment is evaluated in an anechoic room by comparing the total power radiated by full-scale models of the inlet with both reflecting and absorbent walls. It is shown that a 12 dB reduction of the BPF tone can be achieved by using the proposed lining
Published
1997-09-01
How to Cite
1.
Meslioui S-A. Experimental study of the sound reduction for the side air-intake of a helicopter turboshaft engine. Canadian Acoustics [Internet]. 1997Sep.1 [cited 2019Sep.21];25(3):10-. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/1081
Section
Proceedings of the Acoustics Week in Canada