Impact of the fuel time lag distribution in elliptical premix nozzles on combustion stability

Wolfgang Polifke, Jan Kopitz, Ana Serbanovic

Research output: Contribution to conferencePaperpeer-review

38 Scopus citations

Abstract

The impact of premix nozzle shape on combustion stability in a geometry representative of an annular low-emission combustor is investigated by a combination of numerical and analytical means. For three elliptical premix nozzle geometries with varying eccentricity, the flame shape is computed with computational fluid dynamics using a standard stationary Reynolds-averaged formulation with Reynolds-Stress and turbulent flame speed closure models. From the CFD solution, the time lags for convective transport from the fuel injector to the flame front are determined through Lagrangian particle tracking. Interpreting the histograms of particle arrival times as the unit impulse response of fuel consumption to a perturbation of fuel injection, the corresponding fuel transport frequency response F(LJ) is computed and used to achieve closure for a linear acoustic model of the behavior of a compact premix flame. Using this model for the flame dynamics in a network model of linear acoustics in annular geometries, the impact of nozzle shape and fuel transport time lag distribution on the thermo-acoustic stability of a premixed combustor is explored. For the configurations investigated, the elliptical premix nozzles produce wider time lag distributions with smaller mean values than the circular base configuration and are less prone to combustion instabilities.

Original languageEnglish
DOIs
StatePublished - 2001
Event7th AIAA/CEAS Aeroacoustics Conference and Exhibit, 2001 - Maastricht, Netherlands
Duration: 28 May 200130 May 2001

Conference

Conference7th AIAA/CEAS Aeroacoustics Conference and Exhibit, 2001
Country/TerritoryNetherlands
CityMaastricht
Period28/05/0130/05/01

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