Injection System Design Impact on the Stabilization and Acoustic Response of Premixed Swirling Flames

M. Gatti (1) , R Gaudron (1) , Clément Mirat (1) , Thierry Schuller (1)

1 EM2C - Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion

This article reports a series of experiments on the stabilization and acoustic response of swirling lean premixed methane/air flames when the injector system design is modified. The design modifications comprise changes of (1) the main dimensions of a radial swirler, (2) the diameter of the injection nozzle, (3) the diameter of a cone used as a bluff body and (4) the distance L between the swirler and the injector nozzle outlet. In agreement with previous observations, the FTF of these swirling-flames features a drop of the gain in a frequency range that depends on the bulk flow velocity and on the distance L. As the swirl number increases, the difference between FTF gain extrema is found to increase as well, a feature which is more evident when the flow passage area is increased, compared to when the swirler geometry is optimized. It is concluded that, even if the FTF gain decreases for increasing swirl levels, a compromise needs to be found between flame stabilization and acoustic response optimization, since an excessive swirl level could result in flame flashback.

Domaines: Sciences de l'ingénieur [physics]

M. Gatti, R Gaudron, Clément Mirat, Thierry Schuller. Injection System Design Impact on the Stabilization and Acoustic Response of Premixed Swirling Flames. 8th European Combustion Meeting 2017, Apr 2017, Dubrovnik, Croatia. ⟨hal-01877594⟩