Numerical Investigation of Laminar Premixed Flame Response to Acoustic Excitation

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Behzadi, Milad | 2012

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 43665 (45)
University: Sharif University of Technology
Department: Aerospace Engineering
Advisor(s): Farshchi, Mohammad
Abstract:
Flame Response to acoustic excitation which plays an important role in combustion chamber stability state may be found through numerical simulation. A finite volume code of higher order accuracy developed for compressible flows was adopted. Species equations along with a single-step irreversible reaction model were added to this non-reacting program. Changes were also made to the energy equation. Premixed methane/air flame in tubes was studied and the same problem was solved with FLUENT software. It was found that whether the Lewis number is considered constant or temperature dependent has a strong effect on flame structure and shape and that using mean values for gas properties yields out acceptable results for this flame configuration. It is suggested that the code be further developed so that it can be reliably utilized to predict flame-sound interaction. Further more, laminar conical flame was simulated and excited by inlet velocity modulation. Then the response of the flame defined as the ratio of heat release fluctuations to velocity oscillations was obtained for a wide range of frequencies. The predicted results agreed well with available experimens, showing the capability of the method
Keywords:
Premixed Flame ; Combustion Instability ; Numerical Method ; Acoustic Excitation

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