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 language | English |
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DOIs | |
State | Published - 2001 |
Event | 7th AIAA/CEAS Aeroacoustics Conference and Exhibit, 2001 - Maastricht, Netherlands Duration: 28 May 2001 → 30 May 2001 |
Conference
Conference | 7th AIAA/CEAS Aeroacoustics Conference and Exhibit, 2001 |
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Country/Territory | Netherlands |
City | Maastricht |
Period | 28/05/01 → 30/05/01 |