S.D. Erbslöh, W.J. Crowther

This paper describes the application of flow control to a civil turbofan intake for the purpose of relaxing the compressor face distortion due to crosswind constraint at take-off. Wind tunnel experiments were conducted on a 7% scale intake model capable of simulating conditions representative of high thrust at low forward speed and high sideslip angle. The baseline (unactuated) flow topology at these conditions is characterised by a separation line on the windward leading edge of the nacelle, leading to a region of re-circulating flow on the windward wall of the diffuser and a region of reduced total pressure on the windward side of the compressor face. Flow control was implemented using both classical Vane Vortex Generators (VVGs) and Air Jet Vortex Generators (AJVGs). Both these devices work by redistributing the momentum in the boundary layer on the windward lip and hence delaying the separation on the windward leading edge of the nacelle. The VVGs were set at an angle of 18° to the local flow direction and were arranged in a co rotating array. The AJVGs were set at a pitch of 45° and skew of 90°. Experimental results show that compressor face total pressure distortion compared to the unactuated baseline could be reduced by a maximum of 52% using the VVGs and 34% using the AJVGs. For the AJVGs it is shown that the most important parameters affecting flow control efficiency and effectiveness are the jet velocity ratio and the orifice spacing ratio. At experimental scale, the typical bleed requirement for AJVGs is approximately 0.1% of engine mass flow. At full scale, dimensional analysis suggests that the bleed requirement is lower than at model scale.

CEAS/KATnet Conference on Key Aerodynamic Technologies, Bremen, 2005

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 2005, 2005-07, CEAS/KATnet Conference on Key Aerodynamic Technologies - Proceedings; S.1-8; 2005; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

aerodynamics

Bibliothek

2005