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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal align=center style='margin-bottom:12.0pt;text-align:center'><b>ChBE Dept. Seminar<br>10:30am-11:30am, Friday, December 6, 2013<br>Rm W122</b><o:p></o:p></p><p class=MsoNormal align=center style='text-align:center'><b><span style='font-size:14.0pt'>Computational Modeling of Cold Plasma Discharges for Plasma-Assisted Combustion Applications<o:p></o:p></span></b></p><p class=MsoNormal align=center style='text-align:center'><o:p> </o:p></p><p class=MsoNormal align=center style='text-align:center'>Laxminarayan Raja<o:p></o:p></p><p class=MsoNormal align=center style='text-align:center'>University of Texas at Austin<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-align:justify;text-indent:.5in'><b><u><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'>ABSTRACT:</span></u></b><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> </span><span style='font-family:"Times New Roman","serif"'>High fidelity computational modeling study of plasma assisted combustion is discussed in this talk. Non-equilibrium plasmas are found to provide significant advantages to the ignition and flame holding of fuel-air mixtures under high speed flow conditions and in high-pressure automotive engine conditions. The plasma assisted combustion is facilitated by efficient radical production in the plasma as well as other flow-plasma coupling processes. We present a computational simulation study of non-equilibrium streamer discharges in a coaxial electrode and a corona geometry for automotive combustion ignition application. The study was performed using a self-consistent, two-temperature plasma model with finite-rate plasma chemical kinetics. Positive high voltage pulses of order tens of kV and duration of tens of nanoseconds were applied to the powered inner cylindrical electrode which resulted in the formation and propagation of a cathode-directed streamer. The resulting spatial and temporal production of active radical species such as O, H, and singlet delta oxygen is quantified and compared for lean and stoichiometric fuel-air mixtures. For the coaxial electrode geometry, most of the radicals are produced in a secondary streamer that forms in the latter stages of the pulse transient. For the corona geometry, the peak radical production is localized near the high reduced electric field regions of the inner electrode rather than the ionizing streamer head. The stoichiometry of the mixture was observed to have a relatively small effect on both the plasma discharge structure and the resulting yield of radical species. The two-way coupling between fluid mechanics and plasma dynamics in these discharges is discussed.</span><a name="_GoBack"></a><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></b></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>