Autoignition and flame propagation in non-premixed MILD combustion

Journal article (2019)

Authors

Nguyen Anh Khoa Doan University of Cambridge
Nedunchezhian Swaminathan University of Cambridge
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DNS MILD combustion Flameless combustion Ignition Flux analysis
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Published Date

2019-3

Language

English

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Abstract

Direct Numerical Simulation (DNS) data of Moderate or Intense Low-oxygen Dilution (MILD) combustion are analysed to gather insights on autoignition and flame propagation in MILD combustion. Unlike in conventional combustion, the chemical reactions occur over a large portion of the computational domain. The presence of ignition and flame propagation and their coexistence are studied through spatial and statistical analyses of the convective, diffusive and chemical effects in the species transport equations. Autoignition is observed in regions with lean mixtures because of their low ignition delay times and these events propagate into richer mixtures either as a flame or ignition. This is found to be highly dependent on the mixture fraction length scale, ℓZ, and autoignition is favoured when ℓZ is small.