The effect of hydrogen enrichment on the forced response of CH4/H2/Air laminar flames
File(s)
Accepted version
Author(s)
Lim, Zhengli
Li, Jingxuan
Morgans, Aimee S
Type
Journal Article
Abstract
Hydrogen-enrichment of conventional natural gas mixtures is an actively-explored strategy for reducing pollutant emissions from combustion. This study investigates the effect of hydrogen enrichment on the unsteady flame response to perturbations, with a view to understanding the implications for thermoacoustic stability. The Level Set Approach for kinematically tracking the flame front was applied to a laminar conical premixed methane/hydrogen/air flame subjected to 2D incompressible velocity perturbations. For hydrogen enrichment levels ranging from 0% to 80% by volume, the resulting unsteady heat release rate of the flame was used to generate the Flame Describing Functions (FDFs). This was performed across a range of perturbation frequencies and levels at ambient pressure. The mean heat release rate of the flame was fixed at Q_ ¼ 2:69kW and the equivalence ratio was set to ϕ = 1.08 for all hydrogen enrichment levels. Hydrogen-enrichment was found to shift the FDF gain drop-off to higher frequencies, which will increase propensity to thermoacoustic instability. It also reduced the effective flame time delay. Sensitivity analyses at ϕ = 0.8 revealed that the changes in FDF were driven predominantly by the flame burning speed, and were insensitive to changes in Markstein length.
Date Issued
2021-07-06
Date Acceptance
2021-04-27
Citation
International Journal of Hydrogen Energy, 2021, 46 (46), pp.23943-23953
ISSN
0360-3199
Publisher
Elsevier
Start Page
23943
End Page
23953
Journal / Book Title
International Journal of Hydrogen Energy
Volume
46
Issue
46
Copyright Statement
Copyright © Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
http://arxiv.org/abs/2105.05706v1
Subjects
physics.flu-dyn
physics.flu-dyn
Publication Status
Published
Date Publish Online
2021-05-20