微波辅助强化乙炔-空气火花点火的实验研究

Experimental Study of Microwave Assisted Spark Ignition on Expanding C_(2)H_(2)-Air Spherical Flames

利用乙炔-空气球形火焰的发展特性,对比研究了微波辅助点火(MAI)在燃空当量比0.4~1.4、环境压力0.1~0.6MPa,微波脉冲频率1~ 80 kHz、微波馈入时刻-2~2 ms条件下的点火性能增强效能。并通过干放电实验,探究了微波对火焰核心促进作用的内在机制。结果表明:MAI能将常压下当量比分别为0.4和1.4的早期火焰发展速度提升60%和270%;随着环境压力的增大,MAI对早期火焰的增强作用有所减弱;微波脉冲频率从1 kHz增到80 kHz时,MAI的增强效能先快速增强后逐渐放缓;微波提前触发有助于提升MAI性能。

The performance of Microwave Assisted Spark Ignition(MAI)is investigated using expanding acetylene-air spherical flames over equivalence ratio of 0.4~1.4 and ambient pressure of0.1~0.6 MPa in a constant volume combustion chamber.In addition,the influences of microwave pulse frequency of 1~80 kHz and injection timing of-2~2 ms on performance of MAI are explored through both discharge tests and ignition tests.The results show that,the early flame development is accelerated by 60%at equivalence ratio 0.4 and by 270%at equivalence ratio 1.4 with pulse frequency 40 kHz under ambient pressure 0.1 MPa.However,the enhancement of MAI decreases when equivalence ratio approaches to the stoichiometric ratio or ambient pressure increases.In this situation,increasing the pulse frequency and an earlier injection strategy are beneficial to the ignition.