Dynamics of and noise radiated by a perturbed impinging premixed jet flame
Résumé
This paper presents an experimental study of an acoustically excited, premixed, laminar-jet flame impinging on a water-cooled plate. Without excitation, different types of flame shapes are identified. With excitation, a strong noise is produced. The mechanism of flame-induced noise generation is investigated in detail. The results show that the modulation of the flow upstream of the flame produces strong variations in the flame's area and also intense noise emission. The amplitude of the sound exceeds by one or two orders of magnitude that associated with a flame under the same flow modulation, but without the plate. The source of sound is identified as the cyclic extinction of flame area as the jet interacts with the cool plate. The link between the far-field pressure, the chemiluminescence from the flame and the flame surface is successfully compared with classical results of combustion-noise theory.