The impact of chemical modelling on turbulent premixed flame acoustics

Direct numerical simulations are used to study the impact of chemical modelling on the flame dynamics and the sound generated by three-dimensional, turbulent, premixed methane/air jet flames. The semi-global BFER mechanism from Franzelli et al. (Combust. Flame, vol. 159, issue 2, 2012, pp. 621–637)...

Full description

Saved in:
Bibliographic Details
Published in:Journal of fluid mechanics 2021-03, Vol.915, Article A3
Main Authors: Brouzet, D., Talei, M., Brear, M.J., Cuenot, B.
Format: Article
Language:English
Subjects:
Acoustics
Aerodynamics
Air jets
Chemistry
Coffee
Direct numerical simulation
Gas turbines
Heat
Heat release rate
Heat transfer
Jet flow
JFM Papers
Mathematical models
Modelling
Noise
Premixed flames
Sound
Three dimensional models
Turbines
Turbulence
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Direct numerical simulations are used to study the impact of chemical modelling on the flame dynamics and the sound generated by three-dimensional, turbulent, premixed methane/air jet flames. The semi-global BFER mechanism from Franzelli et al. (Combust. Flame, vol. 159, issue 2, 2012, pp. 621–637) and the more complex skeletal COFFEE mechanism from Coffee (Combust. Flame, vol. 55, issue 2, 1984, pp. 161–170) are considered. A more wrinkled flame is observed at downstream locations when using the COFFEE mechanism, demonstrating stronger flame/turbulence interaction. This flame also has a significantly lower acoustic power even though it features more acoustic output at high frequencies. The former is shown to arise from lower fluctuations of the heat release rate, whilst the latter is caused by the COFFEE mechanism creating more wrinkled flame surfaces. These results suggest that the accurate simulation of the noise emitted by turbulent premixed flames requires a chemical mechanism that ensures two main features: the heat release rate profile is important for modelling the overall sound amplitude and low frequency acoustics, whilst the flame/turbulence interaction impacts the higher frequency sound.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2020.1184