Impact of pressure on simulated FREI combustion

Document Type

Conference Proceeding

Publication Date

1-1-2017

Abstract

Flames with repetitive extinction and ignition (FREI) are self-excited instabilities that are observed in externally heated tubular micro-combustors with a controlled wall temperature profile. In FREI, flames ignite in the downstream hot region and move upstream while losing heat, and eventually quench in the upstream cold region. This periodic phenomenon repeats itself at several hundred Hz. The present numerical study seeks to investigate effects of pressure on the behavior of FREI inside a 1mm tubular microchannel. In this study, the impact of pressure is investigated for stoichiometric (F = 1) premixed propane/air mixtures in an axisymmetric 2D configuration. Transient numerical simulations are performed using detailed chemistry. Externally imposed wall temperatures are kept the same for all four cases. Results show that temperature levels characteristic for extinction and ignition decrease as the pressure increases. The decrease is more pronounced for extinction temperatures, which is consistent with a known decrease of the quenching diameter for increasing pressures.

Publication Source (Journal or Book title)

2017 Fall Technical Meeting of the Western States Section of the Combustion Institute, WSSCI 2017

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