定容燃烧室有无废气稀释燃烧特性实验研究

研究了甲醇燃料在有、无废气稀释情况下的燃烧特性，采用定容燃烧室进行实验，并利用激光纹影技术和高速摄影机对火焰图像进行可视化，研究了不同燃烧初始压力、不同化学当量比和废气稀释情况下的燃烧时间和火焰传播情况。结果表明，在贫燃料状态，当化学当量比增大时，燃烧时间明显缩短，在废气稀释情况下，燃烧时间延长，在高初始燃烧压力时，火焰传播速度下降更明显。同时，采用图像技术可以获得初始压力变化和废气稀释情况下非常有用的火焰结构信息。实验表明，当燃烧时间较长时，定容燃烧过程要考虑浮升力的影响。

Experimental Investigation of Combustion Characteristics With and Without Exhaust Gas Dilution in the Constant Volume Combustion Chamber

This paper presented the combustion characteristics of methanol with and without exhaust gas dilution conditions. A constant volume combustion chamber was used for the experiments. The behaviors of the flame were visualized by instantaneous schlieren and direct photography. Effects of initial pressure, equivalence ratio and exhaust gas dilution on burning duration and flame propagation velocity were discussed. The results show that the burning duration can be decreased considerably by the increase of equivalence ratio at lean burning condition. At the exhaust gas dilution condition, the burning duration is extended and the flame speed drops faster at high initial pressure than at low one. Various information can be obtained from the photographs such as the structure of flame front affected by initial pressure and exhaust gas dilution, and it is suggested that the buoyancy must be considered at longer burning duration.