TY - JOUR
T1 - Strategy for single-shot CH3 imaging in premixed methane/air flames using photofragmentation laser-induced fluorescence
AU - Li, Bo
AU - Zhang, Dayuan
AU - Yao, Mingfa
AU - Li, Zhongshan
PY - 2017
Y1 - 2017
N2 - Single-shot imaging of methyl radical (CH3) in premixed methane/air flames is demonstrated using photofragmentation laser-induced fluorescence (PF-LIF) technique. A pump-probe strategy was adopted with the pump laser at 212.8 nm photolyzing CH3, and with the probe laser at 426.8 nm detecting the photolyzed CH (X 2Π) fragments. Spatially resolved spectrograph of the PF-LIF signal from a stable laminar flame was recorded across the reaction zone to investigate potential interferences. The results indicate that the single-photon channel, CH3 + 212.8 nm → CH (X 2Π) + H2, dominates the photofragmentation process. The CH2 radical was excluded from being an interfering precursor of the CH (X 2Π) fragments owing to its relatively low concentration and small absorption cross section. Naturally present CH in the flame was identified as the main interference, but was conservatively estimated to account for only less than 4% of the total PF-LIF signal. Signal-to-noise ratio of around 10 was realized for single-shot imaging of natural CH3 in turbulent jet flames.
AB - Single-shot imaging of methyl radical (CH3) in premixed methane/air flames is demonstrated using photofragmentation laser-induced fluorescence (PF-LIF) technique. A pump-probe strategy was adopted with the pump laser at 212.8 nm photolyzing CH3, and with the probe laser at 426.8 nm detecting the photolyzed CH (X 2Π) fragments. Spatially resolved spectrograph of the PF-LIF signal from a stable laminar flame was recorded across the reaction zone to investigate potential interferences. The results indicate that the single-photon channel, CH3 + 212.8 nm → CH (X 2Π) + H2, dominates the photofragmentation process. The CH2 radical was excluded from being an interfering precursor of the CH (X 2Π) fragments owing to its relatively low concentration and small absorption cross section. Naturally present CH in the flame was identified as the main interference, but was conservatively estimated to account for only less than 4% of the total PF-LIF signal. Signal-to-noise ratio of around 10 was realized for single-shot imaging of natural CH3 in turbulent jet flames.
KW - CH
KW - Laser-induced fluorescence
KW - Photofragmentation
KW - Single-shot imaging
KW - Turbulent methane/air flames
UR - http://www.scopus.com/inward/record.url?scp=85008683497&partnerID=8YFLogxK
U2 - 10.1016/j.proci.2016.07.082
DO - 10.1016/j.proci.2016.07.082
M3 - Article
AN - SCOPUS:85008683497
SN - 1540-7489
SP - 4487
EP - 4495
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
ER -