Experimental and numerical study of cap-like lean limit flames in H 2 -CH 4 -air mixtures
Name:
Zhou_etal_2018_CNF_cap_like_flame_authors.pdf
Size:
3.810Mb
Format:
PDF
Description:
Accepted Manuscript
Type
ArticleAuthors
Zhou, ZhenShoshin, Yuriy
Hernandez Perez, Francisco
van Oijen, Jeroen A.
de Goey, Laurentius P.H.

KAUST Department
Clean Combustion Research CenterDate
2017-11-15Online Publication Date
2017-11-15Print Publication Date
2018-03Permanent link to this record
http://hdl.handle.net/10754/626178
Metadata
Show full item recordAbstract
Lean limit flames of H2-CH4-air mixtures stabilized inside a tube with an inner diameter of 30 mm in a downward flow are studied experimentally and numerically. A transition from bubble-like flames, with a long decaying skirt, to cap-like flames with a sharp visible flame edge at the bottom is observed as the lean flammability limit is approached. This transition is accompanied by formation of a secondary weak flame front inside the cap-like flame. The CH* chemiluminescence distribution of the studied flames is recorded and the velocity field of the lean limit flames is measured using Particle Image Velocimetry (PIV). The flame temperature field is measured utilizing the Rayleigh scattering method. Numerical prediction with a mixture-averaged transport model and skeletal mechanism for CH4 qualitatively reproduces the above experimentally observed phenomena. The presence of negative flame displacement speed for the entire leading edge of the cap-like flames is numerically predicted and experimentally demonstrated. The secondary weak flame front is located in a region with reverse upward flow of the recirculation zone, which is found to support the propagation of the leading edge with a negative flame displacement speed. Furthermore, radiative heat loss has a significant influence on the lean flammability limit of the cap-like flames.Citation
Zhou Z, Shoshin Y, Hernández-Pérez FE, van Oijen JA, de Goey LPH (2018) Experimental and numerical study of cap-like lean limit flames in H 2 -CH 4 -air mixtures. Combustion and Flame 189: 212–224. Available: http://dx.doi.org/10.1016/j.combustflame.2017.10.031.Sponsors
The financial support of the Dutch Technology Foundation (STW), Project 13549, is gratefully acknowledged. The authors thank Prof. Clinton Groth for providing access to the CFFC (Computational Framework for Fluids and Combustion) code.Publisher
Elsevier BVJournal
Combustion and FlameAdditional Links
http://www.sciencedirect.com/science/article/pii/S0010218017304285ae974a485f413a2113503eed53cd6c53
10.1016/j.combustflame.2017.10.031