Decreasing liftoff height behavior in diluted laminar lifted methane jet flames
Jung, Ki Sung
Yoo, Chun Sang
Lee, Byeong Jun
Cha, Min Suk
Chung, Suk Ho
KAUST DepartmentClean Combustion Research Center
Combustion and Laser Diagnostics Laboratory
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2018-06-22
Print Publication Date2018-06
Permanent link to this recordhttp://hdl.handle.net/10754/630497
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AbstractStabilization of laminar lifted coflow jet flames of nitrogen-diluted methane was investigated experimentally and numerically. As the fuel jet velocity was increased, two distinct behaviors in liftoff height were observed depending on the initial fuel mole fraction; a monotonically increasing trend and a decreasing and then increasing trend (U-shaped behavior). The former was observed in the jet-developing region and the latter in the jet-developed region. Because the decreasing behavior of liftoff height with jet velocity has not been observed at ambient temperature, the present study focuses on decreasing liftoff height behavior. To elucidate the physical mechanism underlying the U-shaped behavior, numerical simulations of reacting jets were conducted by adopting a skeletal mechanism. The U-shaped behavior was related to the buoyancy. At small jet velocities, the relative importance of the buoyancy over convection was strong and the flow field was accelerated in the downstream region to stabilize the lifted flame. As the jet velocity increased, the relative importance of buoyancy decreased and the liftoff height decreased. As the jet velocity further increased, the flame stabilization was controlled by jet momentum and the liftoff height increased.
CitationVan K, Jung KS, Yoo CS, Oh S, Lee BJ, et al. (2018) Decreasing liftoff height behavior in diluted laminar lifted methane jet flames. Proceedings of the Combustion Institute. Available: http://dx.doi.org/10.1016/j.proci.2018.05.031.
SponsorsThis work was supported by the National Research Council of Science and Technology (NST) grant by the Korea government (MSIP) No. CRC-14-01-ETRI. MSC and SHC were supported by Clean Combustion Research Center (CCRC), King Abdullah University of Science and Technology (KAUST).