基于急速混合管状火焰技术的丙烷富氧燃烧

Oxy-fuel combustion of propane based on rapidly mixed tubular flame technology

采用燃料与氧化剂分别切向注入柱形燃烧室的急速混合管状火焰燃烧技术,开展了丙烷富氧燃烧实验研究,重点分析了火焰结构和燃烧稳定性随氧气摩尔分数xO_2的变化规律。丙烷空气实验中,急速混合获得了与预混燃烧相近的均匀稳定层流火焰。以CO_2为稀释剂,利用急速混合燃烧分析了不同xO_2的火焰特性。结果表明:当xO_2≤0.5时,在可燃范围内可获得均匀稳定的管状火焰;xO_2=0.6,火焰结构不均匀但仍为稳定层流火焰;xO_2增加至0.7时,仅在低当量比下获得了稳定管状火焰,当量比为1.0附近则出现了不稳定燃烧;随着xO_2进一步增加,不稳定燃烧范围扩大。实验测量了xO_2≤0.4的丙烷可燃界限,相同xO_2下N2为稀释剂的可燃范围比CO_2的大;且在xO_2低至0.125时仍能燃烧,而CO_2为稀释剂时此值为0.18。

An inherently safe technique of rapidly mixed tubular flame combustion,with the fuel and oxidizer individually injected into a combustor,was adopted to investigate the oxy-fuel combustion of propane.The variations of flame structure and combustion stability with oxygen mole fraction were addressed.Based on propane/air combustion,it was found that the rapidly mixed combustion could obtain almost the same flame structure as that of the premixed combustion.Thereafter CO_2 was used as the diluent,and combustion tests were conducted under different oxygen mole fractions.Results illustrated that when oxygen mole fraction was no more than 0.5,a uniform and stable tubular flame can be established from lean to rich limit;by increasing oxygen mole fraction to 0.6,the laminar flame became non-uniform in structure,however,the flame was stable;by raising oxygen mole fraction to 0.7,the stable tubular flame was merely obtained at lean combustion,and oscillatory combustion appeared when the equivalence ratio of 1.0.By further increasing oxygen mole fraction,the oscillation region was expanded.The combustion range for propane/oxygen mixture diluted by N2 and CO_2 was examined when oxygen mole fraction was no more than0.4.It was found that the flammable range diluted by N2 was wider than that diluted by CO_2,and the minimum oxygen mole fraction to sustain propane/oxygen combustion diluted by CO_2 was 0.18,higher than that of 0.125 diluted by N2.