Enhancement of lean blowout limits of swirl stabilized NH3-CH4-Air flames using nanosecond repetitively pulsed discharges at elevated pressures
B. Aravind, Liang Yu, Deanna A. Lacoste
Abstract
This study experimentally examines the impact of nanosecond repetitively pulsed (NRP) discharges on lean premixed methane-ammonia-air swirl flames at pressures up to 4 bar. The results reveal the extension of flame blowout by 10 -12% under atmospheric conditions and 5-6% at 4 bar, when NRP discharges are applied. This decrease in the plasma effect could be attributed to the detrimental impact of strong shock waves at high pressure, destabilizing the flame. NH3-CH4-air flames shows higher lean blowout limits in comparison to CH4-air flames. NRP discharges exhibit consistent impact on the lean blowout limit enhancement across ammonia fractions (20-60%), irrespective of pressure conditions. These results are obtained for a ratio of NRP discharge power to flame thermal power of 0.63 % and constant pulse repetition frequency of 30 kHz.