不同燃烧方式下甲烷与空气火焰光谱特性研究

Spectral characteristics of methane/air flame under different combustion modes

为研究不同燃烧方式下甲烷燃烧火焰光谱特性,利用高速光纤光谱仪分别对预混和扩散燃烧方式下甲烷与空气燃烧火焰光谱进行采集,对比分析了不同燃烧工况中火焰辐射光谱特点,结果表明:在可见光波长范围内,扩散燃烧方式下的光谱强度明显高于预混燃烧;随着空气流量增加, C2*辐射强度呈先增加后下降的趋势,其余三种自由基辐射强度均呈小幅增加趋势,且扩散燃烧火焰中C2*辐射强度峰值明显高于预混燃烧;随着甲烷流量增加,在两种燃烧方式下各自由基辐射强度均呈减少趋势;根据C2*、OH*辐射强度大小与可见光波长范围内连续光谱强度可以判断火焰燃烧方式。

In order to study the spectral characteristics of methane combustion flame under different combustion modes,the methane/air combustion flame spectra of premixed and diffusive combustion modes were detected by a high-speed fiber optic spectrometer.The characteristics of flame radiation spectra in different combustion conditions were compared and analyzed in this paper.The results show that the spectral intensities in the diffusion combustion mode are significantly higher than that in the pre-mixed combustion within the visible wavelength range.As the air flow rate increases,the C2*radiation intensity ascends slightly prior to declining finally.The other three kinds of free radical radiation intensity showed identically a slight ascending trend.And the peak of C2*radiation intensity in the diffusion combustion flame is significantly higher than that of the premixed combustion;As the methane flow rate increases,the radiation intensity of each radical decreases in both combustion modes.Accordingly,the flame combustion mode can be judged according to the C2*、OH*radiation intensity and the continuous spectral intensity within the visible wavelength range.