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Yoo, Chun Sang
Clean Combustion & Energy Research Lab
Research Interests
  • Carbon-free combustion
  • Numerical turbulent combustion
  • Combustion modelling
  • Hydrogen/Ammonia Gas turbine combustion

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Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in heated coflow: flame stabilization and structure

Cited 72 times inthomson ciCited 90 times inthomson ci
Title
Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in heated coflow: flame stabilization and structure
Author
Yoo, Chun SangSankaran, R.Chen, J. H.
Issue Date
2009-12
Publisher
CAMBRIDGE UNIV PRESS
Citation
JOURNAL OF FLUID MECHANICS, v.640, pp.453 - 481
Abstract
Direct numerical simulation (DNS) of the near field of a three-dimensional spatially developing turbulent lifted hydrogen jet flame in heated coflow is performed with a detailed mechanism to determine the stabilization mechanism and the flame structure. The DNS was performed at a jet Reynolds number of 11000 with over 940 million grid points. The results show that auto-ignition in a fuel-lean mixture at the flame base is the main Source of stabilization of the lifted Jet flame. A chemical flux analysis shows the occurrence of near-isothermal chemical chain branching preceding thermal runaway upstream of the stabilization point, indicative of hydrogen auto-ignition in the second limit. The Damkohler number and key intemediate-species behaviour near the leading edge of the lifted flame also verify that auto-ignition occurs at the flame base. At the lifted-flame base, it is found that heat release occurs predominantly through ignition in which the gradients of reactants are opposed. Downstream of the flame base, both rich-premixed and non-premixed flames develop and coexist with auto-ignition. In addition to auto-ignition, Lagrangian tracking of the flame base reveals the passage of large-scale flow Structures and their correlation with the fluctuations of the flame base. In particular, the relative position of the flame base and the coherent flow structure induces a cyclic motion of the flame base in the transverse and axial directions about a mean lift-off height. This is confirmed by Lagrangian tracking of key scalars, heat release rate and velocity at the stabilization point
URI
https://scholarworks.unist.ac.kr/handle/201301/11840
URL
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6774360&fileId=S0022112009991388
DOI
10.1017/S0022112009991388
ISSN
0022-1120
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