Effects of Differential Diffusion on the Stabilization of Unsteady Lean Premixed Flames Behind a Bluff-Body
Type
ArticleAuthors
Kim, Yu Jeong
Lee, Bok Jik
Im, Hong G.

KAUST Department
Clean Combustion Research CenterComputational Reacting Flow Laboratory (CRFL)
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2020-09-29Online Publication Date
2020-09-29Print Publication Date
2021-04Embargo End Date
2021-09-29Submitted Date
2019-12-13Permanent link to this record
http://hdl.handle.net/10754/665375
Metadata
Show full item recordAbstract
Two-dimensional direct numerical simulations were conducted to investigate the effects of differential diffusion on flame stabilization and blow-off dynamics of lean premixed hydrogen–air and syngas–air flames stabilized on a meso-scale bluff-body in a square channel. The unity Lewis number for all species was imposed to isolate the effects of differential diffusion. Four sets of simulation cases were conducted. Two different inflow temperature with unity Lewis number were applied to examine distinct levels of hydrodynamic instability. Each unity Lewis number case was compared with the non-unity Lewis number case to investigate how differential diffusion affects the overall flame responses, instabilities, and blow-off mechanism. For all cases, the overall flame dynamics were observed in several distinct modes as the inflow velocity approaches blow-off limit. One of the primary effects of unity Lewis number was an increased level of hydrodynamic instability due to the lower flame temperature and thus a lower density ratio. The lower gas temperature also led to a weakening of the re-ignition of the quenched local mixture by the product gas entrainment. The combined effects were manifested as suppression of the re-ignition events, leading to a revised conclusion that the ultimate blow-off behavior at high velocity conditions are mainly controlled by the onset of local extinction.Citation
Kim, Y. J., Lee, B. J., & Im, H. G. (2020). Effects of Differential Diffusion on the Stabilization of Unsteady Lean Premixed Flames Behind a Bluff-Body. Flow, Turbulence and Combustion. doi:10.1007/s10494-020-00217-ySponsors
This work was sponsored by King Abdullah University of Science and Technology (KAUST). Computational resources were provided by the KAUST Supercomputing Laboratory (KSL). BJL was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry and Energy (MOTIE) of the Republic of Korea (Grant No. 20181110100290).YJK and HGI were funded by King Abdullah University of Science and Technology (no grant number). BJL was sponsored by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry and Energy (MOTIE) of the Republic of Korea (Grant No. 20181110100290).
Publisher
Springer NatureJournal
Flow, Turbulence and CombustionAdditional Links
http://link.springer.com/10.1007/s10494-020-00217-yae974a485f413a2113503eed53cd6c53
10.1007/s10494-020-00217-y