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

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On the flame stabilization of turbulent lifted hydrogen jet flames in heated coflows near the autoignition limit: A comparative DNS study

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dc.contributor.author Jung, Ki Sung ko
dc.contributor.author Kim, Seung Ook ko
dc.contributor.author Lu, Tianfeng ko
dc.contributor.author Chen, Jacqueline H. ko
dc.contributor.author Yoo, Chun Sang ko
dc.date.available 2021-07-22T08:15:07Z -
dc.date.created 2021-07-16 ko
dc.date.issued 2021-11 ko
dc.identifier.citation COMBUSTION AND FLAME, v.233, pp.111584 ko
dc.identifier.issn 0010-2180 ko
dc.identifier.uri https://scholarworks.unist.ac.kr/handle/201301/53245 -
dc.description.abstract Three-dimensional direct numerical simulations of turbulent lifted hydrogen jet flames in heated coflows are performed with a detailed H2/air chemical mechanism to understand their ignition dynamics and stabilization mechanisms. Turbulent lifted jet flames with four different coflow temperatures, Tc, between 750 K and 1100 K are investigated by examining the instantaneous/time-averaged values and conditional means of heat release rate and species critical to ignition, and by performing a displacement speed analysis and a local combustion mode analysis with an indicator, α. Although Tc at 950 K is higher than the autoignition limit, the flame is primarily stabilized by flame propagation rather than autoignition, while at 1100 K, flame stabilization is found to be highly affected by autoignition. The local combustion mode analysis further reveals that at 950 K, even if a local ignition mode with |α|<1 first appears in the near field of the jet, it develops into a local extinction mode with α<−1 as local temperature decreases due to the excessive mixing of heated coflow and cold H2 within vortical structures, which inhibits the ignition kernel development upstream of the flamebase. At 1100 K, however, a local ignition mode prevails upstream of the flamebase. To further identify the effect of a vortex on the early development of an ignition kernel in a mixing layer between the heated coflow and cold H2, a series of two-dimensional DNSs are performed, varying several vortex parameters and air temperature, as a reference for the more complicated corresponding 3-D turbulent DNS cases. The results substantiate that the development of a vortex in the mixing layer tends to retard the autoignition within the vortex, especially when its temperature is slightly above the autoignition limit. ko
dc.language 영어 ko
dc.publisher Elsevier BV ko
dc.title On the flame stabilization of turbulent lifted hydrogen jet flames in heated coflows near the autoignition limit: A comparative DNS study ko
dc.type ARTICLE ko
dc.type.rims ART ko
dc.identifier.doi 10.1016/j.combustflame.2021.111584 ko
dc.identifier.url https://www.sciencedirect.com/science/article/pii/S0010218021003278?via%3Dihub ko
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