基于火焰发射光谱的转动温度和振动温度的测量

利用光学多通道分析仪(OMA)对酒精和煤油在大气中燃烧时的火焰发射光谱进行了分析.实验发现上述火焰发射光谱在275-600 nm波段范围内存在多支辐射强度很大的带状分子光谱,其中以OH自由基A²Σ⁺→X²Π_r(300-330 nm),CH自由基A²Δ→X²Π(410-440 nm)和C₂自由基A³Π_g→X³Π_u(500-520 nm)电子带系的发射光谱最为强烈.实验中采用高分辨率光栅对OH自由基A²Σ⁺→X²Π_r和CH自由基A²Δ→X²Π电子带系发射光谱的精细结构进行了分析.与此同时,本文基于分子光谱理论计算了不同转动温度和振动温度条件下OH自由基A²Σ⁺→X²Π_r和CH自由基A²Δ→X²Π电子带系发射光谱的强度分布,同时通过理论计算光谱和实验光谱进行比较确定了酒精燃烧火焰的转动温度和振动温度. 关键词： 火焰发射光谱 谱线强度 转动温度 振动温度

Measurements of rotational and vibrational temperatures based on flame emission spectroscopy

This study addresses emission spectra of Air-ethanol and Air-kerosene flames by using optical multichannel analysis system (OMA). Experimental results show that there are several bands of molecular spectrum in a range from 275 to 600nm. Among them, the OH A²Σ⁺→X²Π_r(300—330 nm), the CH A²Δ→X²Π(410—440 nm), and C₂ A³Π_g→X³Π_u (500— 520 nm) emissions have the strongest intensity. In turn, the fine structures of OH (A²Σ⁺→X²Π_r) and CH (A²Δ→X²Π) emission are studied by using a high resolution grating in experiment, and the distributions of spectra intensity are calculated at different rotational and vibrational temperatures based on the molecular spectroscopy. Moreover, by comparing the simulated spectra with the experimental spectra of OH (A²Σ⁺→X²Π_r) and CH (A²Δ→X²Π) emissions, the rotational and the vibrational temperatures of Air-ethanol flame are determined in this paper.