Propagation and extinction behavior of methane/air premixed flames through straight and converging-diverging microchannels

Sayan Biswas, Pei Zhang, Haifeng Wang, Li Qiao

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Propagation and extinction behavior of a CH4/air premixed flame passing through straight and converging-diverging (C-D) microchannels (diameters ranging from 1 to 10 mm) were investigated both experimentally and numerically. The dynamic behavior of flame propagation inside the channels was experimentally studied by using CH chemiluminescence and direct imaging. Three patterns of flame propagation were observed, i.e., the flame can survive, partially extinguish and then re-ignite downstream, or completely extinguish. Regime diagrams showing these different patterns as functions of channel geometry and equivalence ratio were generated for both the straight and C-D channels. Numerical simulations were carried out to explain the experimentally observed flame dynamics inside the channels using detailed CH4/air chemistry. In general, flames were easier to extinguish in C-D channels than in straight channels for a fixed channel diameter and equivalence ratio. Additionally, flames were harder to survive in C-D channels with larger exit-to-throat area ratios. Both heat loss and flame stretch were key factors that can generally cause flame extinction in narrow C-D channels. Heat loss was found to be the primary reason for flame extinction inside the microchannel in comparison with the stretch effect.

Original languageEnglish (US)
Pages (from-to)1395-1406
Number of pages12
JournalApplied Thermal Engineering
Volume148
DOIs
StatePublished - Feb 5 2019
Externally publishedYes

Bibliographical note

Funding Information:
The work was supported by the National Science Foundation with Dr. Song-Charng Kong as the technical monitor.

Publisher Copyright:
© 2018

Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.

Keywords

  • Converging-diverging (C-D) microchannels
  • Extinction
  • Flame propagation
  • Simulations

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