丙烷/空气稀薄预混合气流动下的激光点火特性

基于流动点火平台，在不同当量比和流速下，对丙烷/空气稀薄预混气进行了激光点火实验。研究发现：随着当量比和流速的增加，火焰发展速度加快且火焰面积增大；火焰中的CH^*发光强度随当量比提升有明显提高，通过CH^*的分布及发光强度变化能判断火焰发展阶段。混合气的击穿和点火成功率都随当量比和流速的增加而增加，但改变当量比对成功率的影响比改变流速更大；通过击穿发射光谱中的H/N峰值强度比，可以判断混合气中各组分的含量变化，且使用标定线能确定未知预混合气的当量比。

Laser ignition characteristics in propane/air lean premixed gas flow

Based on a flow-ignition platform, laser ignition experiments were carried out on the propane/air lean premixed gas for different equivalence ratios and velocities of flow. The study found that with the increase of the equivalence ratio and velocity of flow, the flame development speed increased and the flame area increased; the CH* luminous intensity in the flame increased significantly with the increase of the equivalence ratio, and the stage of flame development could be judged by the CH* distribution and luminous intensity changes. The probability of successful breakdown and ignition of the mixed-gas increased with the increase of the equivalence ratio and the velocity of flow, but the change of the equivalence ratio had a greater impact on the probability than the velocity of flow; the changes of the content of each component in the mixed gas could be judged by the H/N peak intensity ratio in the breakdown emission spectrum, and the calibration line could determine the equivalence ratio of the unknown premixed gas.