# Mécanismes de couplage dans les interactions acoustiques-combustion

Abstract : Interactions between flames and perturbations of the flow leading to self-sustained combustion oscillations are considered. Based on observations, theoretical or numerical models of these interactions are proposed. Predictions are compared to experiences. It is shown that a fast rate of change of the flame surface area constitutes a strong source of combustion noise. These sources are characterized during flame-wall interaction and during mutual annihilation of neighboring flame front elements. These two phenomena may in turn generate a combustion instability. The coupling mechanism between the unsteady combustion and the burner acoustics is analyzed in these situations. Using a combined approach, a method is developed to predict the stability map of laminar annular burners. The response of the flame to forced modulations of the flow is a key element in the analysis of the stability of a burner. In many industrial furnances the flame is inclined with respect to the flow direction. A theoretical analysis and a numerical model of the response of inclined premixed flame to incident flow perturbations are envisaged. A unified model is developed which extends the validity of previous modelings restricted to low frequencies to convective flow perturbations. Predictions are compared to measurements for a conical flame and a V" flame attached to a rod. The unified model improves the flame transfer function results for the conical flame. The V" flame case is less well predicted because of the roll-up of vortices in the mixing layer between the reactive jet and the surrounding air. Observations, models and methods of analysis proposed in this manuscript improves our understanding of more realistic situations.
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Cited literature [176 references]

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Contributor : Thierry Schuller <>
Submitted on : Sunday, February 10, 2008 - 7:25:43 PM
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### Identifiers

• HAL Id : tel-00250137, version 1

### Citation

Thierry Schuller. Mécanismes de couplage dans les interactions acoustiques-combustion. Energie électrique. Ecole Centrale Paris, 2003. Français. ⟨tel-00250137⟩

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