TY - JOUR
T1 - Counterflow flame experiments and chemical kinetic modeling of dimethyl ether/methane mixtures
AU - Reuter, Christopher B.
AU - Zhang, Rui
AU - Yehia, Omar R.
AU - Rezgui, Yacine
AU - Ju, Yiguang
N1 - Funding Information:
This research is funded by NSF grant CBET-1507358 . CBR acknowledges support from the DoD National Defense Science and Engineering Graduate (NDSEG) Fellowship program. ORY is grateful for support from the Daniel and Florence Guggenheim Foundation Fellowship at Princeton University.
Funding Information:
This research is funded by NSF grant CBET-1507358. CBR acknowledges support from the DoD National Defense Science and Engineering Graduate (NDSEG) Fellowship program. ORY is grateful for support from the Daniel and Florence Guggenheim Foundation Fellowship at Princeton University.
Publisher Copyright:
© 2018 The Combustion Institute
PY - 2018/10
Y1 - 2018/10
N2 - As advanced engines become more controlled by the fuel reactivity, it is important to have a complete understanding of combustion chemistry of fuel blends at both high and low temperatures. While the high-temperature chemistry coupling with transport and heat release can be examined through the use of flame experiments, low-temperature chemistry has been traditionally limited to homogeneous reactor experiments at fixed temperatures, which leaves the heat release rate unconstrained. In this study, the kinetic coupling between dimethyl ether and methane is examined by studying hot flames, cool flames, and ozone-assisted cool flames in a counterflow burner. At fixed fuel mass fraction, it is found that methane addition to dimethyl ether raises the hot flame extinction limit but lowers the cool flame extinction limit. Ozone addition to cool flames is seen to lead to a substantial increase in the extinction limit, but it also produces a decrease in sensitivity of the extinction limit to the fuel mass fraction. The cool flame extinction measurements are then used to examine the uncertainties of reactions contributing significantly to the low-temperature heat release. The measurements indicate that the original kinetic model significantly overpredicts the cool flame extinction limits. However, by targeting the H-abstraction reaction of dimethyl ether by OH, among other reactions, an updated chemical kinetic model for dimethyl ether/methane mixtures is developed and validated. This study shows the value of the ozone-assisted counterflow cool flame platform in examining the key low-temperature reactions contributing to the heat release rate in cool flames.
AB - As advanced engines become more controlled by the fuel reactivity, it is important to have a complete understanding of combustion chemistry of fuel blends at both high and low temperatures. While the high-temperature chemistry coupling with transport and heat release can be examined through the use of flame experiments, low-temperature chemistry has been traditionally limited to homogeneous reactor experiments at fixed temperatures, which leaves the heat release rate unconstrained. In this study, the kinetic coupling between dimethyl ether and methane is examined by studying hot flames, cool flames, and ozone-assisted cool flames in a counterflow burner. At fixed fuel mass fraction, it is found that methane addition to dimethyl ether raises the hot flame extinction limit but lowers the cool flame extinction limit. Ozone addition to cool flames is seen to lead to a substantial increase in the extinction limit, but it also produces a decrease in sensitivity of the extinction limit to the fuel mass fraction. The cool flame extinction measurements are then used to examine the uncertainties of reactions contributing significantly to the low-temperature heat release. The measurements indicate that the original kinetic model significantly overpredicts the cool flame extinction limits. However, by targeting the H-abstraction reaction of dimethyl ether by OH, among other reactions, an updated chemical kinetic model for dimethyl ether/methane mixtures is developed and validated. This study shows the value of the ozone-assisted counterflow cool flame platform in examining the key low-temperature reactions contributing to the heat release rate in cool flames.
KW - Cool flame
KW - Counterflow diffusion flame
KW - Dimethyl ether
KW - Extinction limit
KW - Methane
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U2 - 10.1016/j.combustflame.2018.06.004
DO - 10.1016/j.combustflame.2018.06.004
M3 - Article
AN - SCOPUS:85048738807
SN - 0010-2180
VL - 196
SP - 1
EP - 10
JO - Combustion and Flame
JF - Combustion and Flame
ER -