15min:

YVETTE ZUZEEK, INCHUL CHOI, SHERRIE BOWMAN, IGOR V. ADAMOVICH AND WALTER R. LEMPERT, Department of Mechanical Engineering, The Ohio State University, 201 W. 19th Ave., Columbus OH, 43210.

Pure rotational Coherent Anti-Stokes Raman Scattering (CARS) is used to study low temperature plasma kinetics and ignition in a repetitively pulsed nanosecond discharge in air and hydrogen-air at stoichiometric and fuel lean conditions at 40 Torr pressure. Air and hydrogen-air mixtures are excited by a burst of high-voltage nanosecond pulses at a 40 kHz pulse repetition rate and 10 Hz burst repetition rate. The number of pulses within the burst has been varied from a few pulses to 1,000 pulses. These temperature measurements are then compared to a hydrogen-air plasma chemistry model which includes nonequilibrium plasma processes and low temperature hydrogen-air chemistry. Sensitivity analysis shows that generation of radicals by the nanosecond discharge is critical to low temperature plasma chemical fuel oxidation and associated heat release. With phi = 1.0 and phi = 0.5, a distinct maximum in temperature with respect to discharge burst duration is observed, as predicted by the code, indicative of ignition occurring.