Flame Quenching at Walls: A Source of Sound Generation

Abdulla Ghani (1) , Thierry Poinsot (2)

1 TUM - Technische Universität Munchen - Technical University Munich - Université Technique de Munich
2 IMFT - Institut de mécanique des fluides de Toulouse

This paper presents a numerical study of head on quenching (HOQ) (an extreme case of flame/wall interactions) as a source of sound generation, which in turn can trigger combustion instabilities and enhanced noise levels. High-fidelity numerical simulations are performed to investigate the impact of wall temperature, high chamber pressures and Lewis number of the fuel on the noise generation. It is demonstrated by theory and simulations that the underlying mechanism of sound generation is flame surface destruction (flame annihila- tion). Special emphasis is put on chemical modeling where simple and complex mechanisms were compared: it is shown that simple chemistry simulations overestimate the generated pressure peaks due to a too fast extinction of the heat release rate compared to the complex scheme. In contrast to the simple mechanism, the complex scheme accounts for minor and intermediate species production and destruction which slows down the extinction process and thus lead to a lower sound level. This effect has to be taken into account, especially in the context of Large Eddy Simulation (LES) of combustion instabilities and combustion noise where simple chemical descriptions are often employed.

Mots clés: Head on quenching; Noise generation; Chemistry modeling

Domaines: Mécanique des fluides [physics.class-ph]

Abdulla Ghani, Thierry Poinsot. Flame Quenching at Walls: A Source of Sound Generation. Flow, Turbulence and Combustion, 2017, vol. 99 (n° 1), pp. 173-184. ⟨10.1007/s10494-017-9810-5⟩. ⟨hal-01548373⟩