报告内容摘要：

The directly fired supercritical carbon dioxide (sCO2) power cycle has high efficiency while allowing nearly complete carbon dioxide (CO2) capture. The operating condition of sCO2 power cycle (10 MPa to 30 MPa) combustors is dramatically different from conventional gas turbine combustors. However, combustion properties, e.g., autoigntion delays, have never been reported under sCO2 conditions. An urgent question to be answered for supercritical carbon dioxide oxy-combustion is how well existing chemical kinetic models perform as no experimental data exists at relevant conditions. For the first time, autoignition delays at sCO2 condition are reported for CH4/O2/CO2 mixtures above the CO2 critical pressure (approximately 100 bar) and temperature range of 1274 to 1433 K. Experiments reveal that a widely used kinetic model, GRI 3.0, underpredicts the ignition delay by a factor of 3. However, kinetic models Aramco 2.0, USC Mech II and HP-Mech are capable of predicting autoignition delays though not validated at these conditions. At high pressure conditions CH3 recombination to form C2H6 through CH3+CH3+M=C2H6+M becomes dominant compared to direct oxidation to form CH3O. The branching ratio of these two reaction pathways dictates the autoignition delays. Further simulation shows that autoignition delay is not sensitive to the third body collision efficiency of CO2.  

报告人简介：

Dr. Wenting Sun is currently an assistant professor of Georgia Institute of Technology, School of Aerospace Engineering. He received his B.E/M.E degrees from Tsinghua University, Department of Engineering Physics in 2005 and 2007, respectively, and Ph.D degree from Princeton University, Department of Mechanical and Aerospace Engineering in 2013. His current research focuses on combustion kinetics, model reduction, plasma-assisted combustion, and laser diagnostics. He has been awarded the Bernard Lewis Fellowship from the Combustion Institute, and Distinguished Paper Award at the 33rd International Symposium on Combustion. He is a 2016 Air Force Office of Scientific Research Young Investigator Program Awardee.

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