低温等离子体点火乙炔／空气爆震特性试验

Experimental research on detonation combustion of acetylene／air mixture igniting by low-temperature plasma

摘要:

为研究交流驱动低温等离子体点火触发爆震特性,在长1.5 m、内径60 mm的爆震管上,以乙炔为燃料,空气为氧化剂,按分压法配气,通过循环,使爆震管内混气混合均匀,进行气相单次爆震实验．采用交流驱动低温等离子体点火,单次放电时间0.5 ms,放电能量约为0.2 J．在点火的同时,用压力传感器和离子探针同时采集爆震管内的压力波和火焰传播特性．实验表明:交流驱动低温等离子体实现了乙炔／空气点火起爆过程,余气系数0.6及1.0混气产生很强的爆震波,余气系数下降,混气压力下降,爆震波传播速度和峰值压力下降,DDT距离和时间增加;余气系数1.4混气不能产生爆震波．

Abstract:

In order to obtain the characterization of AC driven low-temperature plasma initiating the detonation combustion, single-trial detonation has been ignited by low-temperature plasma using acetylene as fuel and the air as oxidant in a 1.5 m long detonation tube and with 60 mm inner diameter. The air and acetylene were filled in the tube according to Dalton law of additive pressure. The air and acetylene would be mixed uniformly by circulating pump. The discharge time of the AC driven low-temperature plasma igniter was 0.5 ms and the energy was 0.2 J once. Meanwhile, propagation characteristics of flame and pressure wave were measured by ion probes and pressure sensors. The experimental results indicated that low-temperature plasma ignited detonation combustion successfully in the mixture when the excess air coefficients were 1.0 and 0.6; the peak pressure values of detonation waves reduced as the initial pressure and the excess air coefficient went down, meanwhile the DDT (Deflagration to Detonation Transition) time and distance increased. Detonation waves cannot be generated in the detonation tube when the excess air coefficient was 1.4.