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Communication Dans Un Congrès Année : 2021

Responses of lean swirling spray flames to acoustic pressure and transverse velocity perturbations

Résumé

Lean liquid-fuel combustion is a promising solution to reduce the polluting emissions of aircraft engines and gas turbines. However, such operating conditions lead more easily to thermo-acoustic instabilities, generally coupled with an azimuthal mode of the cavity, which can be spinning, standing, or a combination of both. With a standing wave, flames are subjected to perturbations in pressure or transverse velocity, depending on their location in the acoustic field. While it is generally admitted that the flame response is mainly dominated by an axial flow oscillation induced by a pressure perturbation, the response of a flame to transverse velocity perturbations is less documented. This is all the more true with spray flames, for which the responses of the gaseous phase and of the liquid phase are different. This paper explores the responses of a linear array of three swirling spray flames at two locations of a standing transverse acoustic field, one characterized by a pressure perturbation and the other by a combination of pressure and transverse velocity perturbations. The Flame Describing Function based on local pressure fluctuations is used to analyze the global flame response. High-speed OH*-imaging is performed in order to evaluate the space-time evolution of the flame response. Spray dynamics is finally examined through PDPA measurements, showing the space-time modulation of the spray, which leads to inhomogeneities in equivalence ratio in the flame zone. The results obtained help to understand the mechanisms leading to the response of swirling spray flames.
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Dates et versions

hal-03717261 , version 1 (08-07-2022)

Identifiants

  • HAL Id : hal-03717261 , version 1

Citer

Clément Patat, Françoise Baillot, Jean-Bernard Blaisot, Eric Domingues. Responses of lean swirling spray flames to acoustic pressure and transverse velocity perturbations. Symposium on Thermoacoustics in Combustion: Industry meets Academia (SoTiC 2021), Sep 2021, Munich, Germany. ⟨hal-03717261⟩
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