TY - JOUR
T1 - Low-temperature chemistry triggered by probe cooling in a low-pressure premixed flame
AU - Zhang, Xiaoyuan
AU - Zhang, Yan
AU - Li, Tianyu
AU - Li, Yuyang
AU - Zou, Jiabiao
AU - Dagaut, Philippe
AU - Yang, Jiuzhong
AU - Li, Wei
AU - Zeng, Meirong
AU - Jin, Hanfeng
AU - Yuan, Wenhao
AU - Qi, Fei
N1 - Funding Information:
The authors are grateful for the funding support from National Natural Science Foundation of China ( 51622605 , 51761135111 , 91541201 , U1832171 ) and the Shanghai Science and Technology Committee (No. 17XD1402000 ). Xiaoyuan Zhang appreciates China Scholarship Council (CSC) for the financial support to visit I.C.A.R.E. (C.N.R.S.–I.N.S.I.S.).
Publisher Copyright:
© 2019 The Combustion Institute
PY - 2019/6
Y1 - 2019/6
N2 - Previous studies on sampling probe effects in the premixed flat flame showed that the temperature in the preheat zone can be lowered down to low-temperature oxidation regime (e.g., 400–800 K). In order to investigate the contribution of the low-temperature chemistry in flame-sampling experiments, a stoichiometric laminar premixed flat flame of ethylene/oxygen/argon was investigated at 30 Torr using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) in this work. Ethyl hydroperoxide (C2H5OOH) was identified and quantified in the present experiment, providing an experimental evidence for the existence of low-temperature chemistry in flame-sampling experiments. In addition to C2H5OOH, the formation of several other intermediates like ethanol and formaldehyde was also influenced by the low-temperature chemistry in the present flame-sampling experiment. A literature kinetic model (Hashemi et al., 2017) was used for predictions and analyses. The difference between the predicted maximum mole fractions of C2H5OOH with the perturbed and unperturbed temperature profiles can reach up to five orders of magnitude. The great improvement of the predictions with the perturbed temperature profiles indicates that the observed low-temperature chemistry in the present flame sampling experiment originates from the probe-induced perturbations, which lowers down the temperature window of the preheat zone and leads to a temperature drop of more than 400 K compared with the unperturbed temperature profile. Through modeling analysis, the low-temperature oxidation chemistry of ethylene involved in the present flame-sampling experiment was discussed. The influence of low-temperature chemistry in the present experiment has also been demonstrated by comparing the model predictions with/without key reactions at low temperatures. It is concluded that predicted maximum mole fractions of several low-temperature chemistry related intermediates, i.e. C2H5OOH, ethanol and formaldehyde, are strongly reduced without these reactions, while low-temperature chemistry only has negligible influence on the predictions of the fuel and the majority of flame intermediates. Furthermore, preliminary experiments were also conducted in ethane, propene and n-butane flames under similar conditions, where hydroperoxides can also be observed.
AB - Previous studies on sampling probe effects in the premixed flat flame showed that the temperature in the preheat zone can be lowered down to low-temperature oxidation regime (e.g., 400–800 K). In order to investigate the contribution of the low-temperature chemistry in flame-sampling experiments, a stoichiometric laminar premixed flat flame of ethylene/oxygen/argon was investigated at 30 Torr using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) in this work. Ethyl hydroperoxide (C2H5OOH) was identified and quantified in the present experiment, providing an experimental evidence for the existence of low-temperature chemistry in flame-sampling experiments. In addition to C2H5OOH, the formation of several other intermediates like ethanol and formaldehyde was also influenced by the low-temperature chemistry in the present flame-sampling experiment. A literature kinetic model (Hashemi et al., 2017) was used for predictions and analyses. The difference between the predicted maximum mole fractions of C2H5OOH with the perturbed and unperturbed temperature profiles can reach up to five orders of magnitude. The great improvement of the predictions with the perturbed temperature profiles indicates that the observed low-temperature chemistry in the present flame sampling experiment originates from the probe-induced perturbations, which lowers down the temperature window of the preheat zone and leads to a temperature drop of more than 400 K compared with the unperturbed temperature profile. Through modeling analysis, the low-temperature oxidation chemistry of ethylene involved in the present flame-sampling experiment was discussed. The influence of low-temperature chemistry in the present experiment has also been demonstrated by comparing the model predictions with/without key reactions at low temperatures. It is concluded that predicted maximum mole fractions of several low-temperature chemistry related intermediates, i.e. C2H5OOH, ethanol and formaldehyde, are strongly reduced without these reactions, while low-temperature chemistry only has negligible influence on the predictions of the fuel and the majority of flame intermediates. Furthermore, preliminary experiments were also conducted in ethane, propene and n-butane flames under similar conditions, where hydroperoxides can also be observed.
KW - Hydroperoxide
KW - Laminar premixed flame
KW - Low-temperature chemistry
KW - Probe-induced perturbation
KW - SVUV-PIMS
UR - http://www.scopus.com/inward/record.url?scp=85063407617&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2019.03.021
DO - 10.1016/j.combustflame.2019.03.021
M3 - Article
AN - SCOPUS:85063407617
SN - 0010-2180
VL - 204
SP - 260
EP - 267
JO - Combustion and Flame
JF - Combustion and Flame
ER -