Modeling of combustion noise spectrum from turbulent premixed flames

Yu Liu , Ann Dowling , Thomas Dunstan , Nedunchezhian Swaminathan

Turbulent combustion processes generate sound radiation due to temporal changes of the total heat release fluctuations within the flame volume. The temporal correlation of the heat release rate fluctuations has not been investigated sufficiently in prior literature due to the difficulty in acquiring heat release rate data from high-fidelity numerical simulations and measurements. In this work, this temporal correlation and its role in the modeling of combustion noise spectrum are studied by analyzing direct numerical simulation (DNS) data of turbulent premixed V-flames. The resulting correlation model is applied to the prediction of far-field combustion noise using different reference time scales. The comparison with recent measurements of open turbulent premixed flames show that the correlation model captures the essential shape of the combustion noise spectrum. Reasonable agreement in the peak frequency and peak sound pressure level (SPL) is also achieved for two turbulent time scales. Further work for the DNS of a Bunsen flame is suggested to study a promising convective time scale $L_f/U_\mathrm{ave}$ where $L_f$ is the flame length and $U_\mathrm{ave}$ is the mean flow velocity.

Mots clés: combustion noise; turbulent premixed flames; correlation of heat release rate; spectral characteristics

Domaines: Acoustique [physics.class-ph]

Yu Liu, Ann Dowling, Thomas Dunstan, Nedunchezhian Swaminathan. Modeling of combustion noise spectrum from turbulent premixed flames. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811265⟩