E.J. Gutmark, T.P. Parr

An active control method designed to improve combustion was demonstrated in open and enclosed systems. The control is based on synchronized acoustical modulation of fuel injection into acoustically forced air vortices at a timing which ensures energizing of the vortices and homogeneous mixing. Laser diagnostics were utilized to obtain simultaneous planar visualizations of the mixing process between the fuel and air flows as well as the combustion zone, indicated by OH, and soot production regions. It was shown that a proper timing of fuel injection results in homogeneous fuel/air mixing within the vortices, while injection which is out of phase with the proper one results in interference with the vortex formation and islands of unmixed fuel, leading to poor combustion. The interaction of the forced reacting jet with the external air was studied using Particle Imaging Velocimetry (PIV). It was determined that the entrained air is crucial to maintain control authority on the combustion. Blockage of the entrained external air resulted in the loss of control. A method for substitution for the external air by direct injection of air into the air jet base was developed. Its efficacy was demonstrated in open and enclosed systems. The latter is especially significant due to the lack of air rich flow in the ambient of such systems. The secondary air injection doubled the flame temperature near the flame holder of an enclosed flame.

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.411-418; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1995