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Article Dans Une Revue Proceedings of the Combustion Institute Année : 2007

An experimental investigation of flame propagation through a turbulent stratified mixture

Résumé

Propagation of a propane/air flame is investigated through a spatially stratified mixture and turbulent flows. An unsteady jet is injected in a constant volume chamber to generate a turbulent flow and a mixture stratification. The flame is spark-ignited in a near stoichiometric mixture and then propagates towards lean mixtures. Simultaneous particle image velocimetry (PIV) and laser induced fluorescence (LIF) measurements are performed to study flame propagation. These measurements provide instantaneous velocity and equivalence ratio fields enabling conditioned measurements in the region ahead of the flame front. Quantitative equivalence ratio measurements are obtained from the fluorescence of a molecular tracer seeding propane by a method based on oxygen quenching of the excited state. The flame is submitted to large-scale and small-scale variations of mixture in a turbulent flow. The flame is ignited on the jet axis and propagates towards the jet boundary. To isolate the effects of mixture stratification from those of turbulence, flame propagation is also investigated for the same aerodynamic jet conditions, but with three different homogeneous mixtures. First, the global enhancement of flame propagation, thanks to mixture stratification, is demonstrated from analysis of the tomography images compared to flame behavior in homogeneous mixtures. Second, the pdfs of local burning velocity conditioned on the local equivalence ratio are obtained and compared with the homogeneous case. These results show that in a turbulent flame, the local burning velocity can increase or decrease depending on the local mixture and mixture distribution along the flame front. (C) 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Dates et versions

hal-00638764 , version 1 (07-11-2011)

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Nathalie Pasquier, Bertrand Lecordier, Michel Trinite, Armelle Cessou. An experimental investigation of flame propagation through a turbulent stratified mixture. Proceedings of the Combustion Institute, 2007, 31, pp.1567-1574. ⟨10.1016/j.proci.2006.07.118⟩. ⟨hal-00638764⟩
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