利用同步辐射研究乙醇和二甲醚低压预混火焰成分

在低压预混层流火焰条件下,利用同步辐射光电离技术,结合分子束质谱法,对当量比为1的二甲醚和乙醇火焰进行了研究.通过扫描火焰中光子的能量,描绘出PIE曲线,探测到了这两种燃料燃烧过程中包含的同分异构中间产物;同时,通过扫描燃烧炉不同位置的光子能量谱,获得了火焰中重要物质的摩尔分数.比较两者的火焰结构,结果表明,这一对同分异构的燃料燃烧时,由于分子结构不同,它们的中间产物和相同中间产物的摩尔分数有很大差异,含氧的中间产物摩尔分数有较大差异.另外,在二甲醚火焰中还发现了甲乙醚,拓宽了对含氧碳氢化合物燃烧的认识.

Study on Composition of Low-Pressure Premixed Ethanol and Dimethy Ether Flames with Synchrotron Radiation

A molecular-beam flame-sampling photoionization mass spectrometer with synchrotron radiation is applied to the measurement of mole fractions in low-pressure premixed stoichiometric ratio(φ=1) DME/oxygen/argon and ethanol/oxygen/argon flat flames. Flame species,including isomeric intermediates,are unambiguously identified with measurements of photoionization efficiency spectra by scanning photon energy. And in the meantime,mole fraction profiles of most observed species are measured by scanning the burner position at selected photon energies near ionization thresholds. The comparisons of the chemical structures of two flames have been made,based on the comprehensive experimental data. It is concluded that different structural features of fuel molecules will cause great variation in intermediate pools,in mole fraction of the same intermediates,and especially in oxygenated intermediates. They further confirm the presence of ethyl methyl ether,a molecule previously unobserved in flames and not included in the present flame models,and this widens the knowledge of oxygenated hydrocarbon combustion.