Intermittency as a transition state in combustor dynamics: an explanation for flame dynamics near lean blowout

Nair, Vineeth ; Sujith, R. I. (2015) Intermittency as a transition state in combustor dynamics: an explanation for flame dynamics near lean blowout Combustion Science and Technology, 187 (11). pp. 1821-1835. ISSN 0010-2202

Full text not available from this repository.

Official URL: http://www.tandfonline.com/doi/abs/10.1080/0010220...

Related URL: http://dx.doi.org/10.1080/00102202.2015.1066339

Abstract

The dynamic transitions preceding lean blowout were investigated experimentally in a laboratory scale turbulent combustor by systematically varying the flow Reynolds number (RE). Previous studies on combustor dynamics have shown that the onset of large-amplitude, combustion-driven oscillations is, at times, presaged by intermittent bursts of high-amplitude periodic pressure pulsations. These intermittent bursts appear in a near random fashion amidst regions of aperiodic low-amplitude fluctuations, provided the underlying flow-field is turbulent. In the present study, we show that intermittent burst oscillations are also observed in combustors close to the lean blowout limit. We show that such intermittent oscillations emerge through the establishment of homoclinic orbits in the phase space of pressure oscillations. The formation of such orbits points to the complex nature of the interaction between the hydrodynamics and acoustic subsystems, which operate over a range of different time scales. High-speed flame images reveal that the intermittent states observed prior to lean blowout correspond to aperiodic detachment of the flame from the bluff-body lip. These findings are consistent with other reports of possibly intermittent states in the literature.

Item Type:Article
Source:Copyright of this article belongs to Taylor & Francis Group.
Keywords:Intermittency; Lean Blowout; Thermoacoustics; Turbulent Combustion
ID Code:109943
Deposited On:21 Dec 2017 11:00
Last Modified:21 Dec 2017 11:00

Repository Staff Only: item control page