不同稀释气体下等离子体辅助甲烷点火

等离子体由于可以同时在燃料反应中增加化学效应与热效应,有望成为辅助点火的有效技术途径。构建了基于激波管的等离子体辅助甲烷点火实验系统,测量了甲烷自点火、持续放电以及放电后断电条件下的点火延迟时间,分析了不同稀释气体下等离子体对甲烷点火延迟的缩短效果。构建了等离子体发射光谱测量系统,测量了放电单元中的发射光谱。在实验条件下,点火温度越高,持续放电下活性粒子的浓度越高。较小的放电功率(4 W)即可将甲烷的点火延迟时间缩短30%~95%。稀释气体为Ar时,等离子体在点火温度小于1 000 K或大于1 400 K时对甲烷点火延迟时间缩短作用更好。稀释气体为N2时,随着点火温度的升高,等离子体对甲烷点火延迟时间作用效果随之降低。

Plasma assisted methane ignition under different diluent gas

Plasma could increase chemical and heat effect at the same time during the fuel reaction and it is expected to be an effective technical way of ignition assistance.Plasma assisted methane ignition experiment system was built based on shock tube.The methane ignition delay time of autoignition,under continuous discharge and when discharge is cut down was measured.The plasma's effect to shorten methane ignition delay under different diluent gas was analyzed.The plasma emission spectrum measurement system was built and the emission spectrum in discharge unit was measured.The active particle concentration is higher with higher ignition temperature under experimental condition.The methane ignition delay time could be shortened by 30％ to 95％ by a little discharge power (＜4W).The shortening effect of plasma is better when the ignition temperature is lower than 1 000 K or higher than 1 400 K with the diluent gas Ar.The shortening effect of plasma decreases with the increase of ignition temperature with the diluent gas N2.