在带有预燃室的大缸径定容燃烧系统中进行甲烷/空气射流引燃主燃室内预混气体的实验研究.基于MATLAB软件平台编写火焰图像批处理算法,并通过该算法进行图像预处理进而获取特征参数；通过分析瞬时压力曲线以及高速摄影仪拍摄的火焰传播图像，研究甲烷/空气预混射流火焰的传播特性以及初始压力和过量空气系数等初始条件对射流火焰发展过程及火焰传播速度的影响.研究结果表明：位于预燃室中的火花塞偏置会造成主燃室内的引燃射流火焰的不均衡发展，且这种不均衡性在过量空气系数越小时愈发严重；射流火焰传播速率随初始压力和过量空气系数的增大而减小，并且当过量空气系数较小(λ=0.8)时，射流火焰对背压的变化较为敏感.
To explore the ignition characteristics of methane/air mixture generated by the pre-chamber turbulent jets, experimental studies were conducted in a large bore constant volume chamber. The flame image batch processing was conducted by using MATLAB software to obtain the flame characteristic parameters. By analyzing the pressure variations and flame images taken by a high-speed camera, the effects of air-fuel equivalence ratios and pre-mixed pressures on jet flame ignition process and flame propagation were studied. The results show that the jet flames in the main chamber are asymmetry, which can be even worse when the air-fuel equivalence ratio is lower due to the asymmetric orientation of the spark plug. As the initial pressure or air-fuel equivalence ratios increase, the flame propagation becomes slower. Furthermore, with the lower air-fuel equivalence ratio (λ=08), the flame propagation tends to be more sensitive to the back pressure variation.
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