Effects of CO2 dilution on turbulent premixed flames at high pressure and high temperature
Effects of CO2 dilution on turbulent premixed flames at high pressure and high temperature
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DOI：
10.1016/j.proci.2006.07.159
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Hideaki Kobayashi;H. Hagiwara;H. Kaneko;Yasuhiro Ogami
中科院分区：
文献类型：
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作者：
Hideaki Kobayashi;H. Hagiwara;H. Kaneko;Yasuhiro Ogami
为了研究废气再循环（EGR），特别是EGR气体中CO2的含量对湍流火焰特性的影响，对高温高压下CH 4和CO2稀释空气的湍流预混火焰进行了实验研究。最大的CO2稀释比，定义为CO2的摩尔分数的空气和CO2的比例，是0.1。将混合物预热至573 K，最高压力为1.0MPa。混合物的本生型湍流预混火焰在高压室中稳定。进行了火焰的OH-PLIF可视化。通过对OH-PLIF图像的分析，计算了湍流燃烧速度、湍流火焰区平均体积和平均燃料消耗率。结果表明，湍流燃烧速度，ST，归一化使用层流燃烧速度，SL，变得更小，当混合物被稀释与CO2。当湍流火焰区被定义为在λ c =0.1和λ c =0.9之间的区域时，在CO2稀释的情况下，火焰区的平均体积增加。随着CO2稀释比的增加，火焰区的平均燃料消耗率降低。这种影响比由于CO2稀释导致的燃料质量分数的降低更强。在CO2稀释的情况下，火焰阵面的最小湍流尺度随湍流雷诺数的减小比无CO2稀释的情况下更明显，这与先前提出的湍流和固有火焰不稳定性的尺度关系相一致.这些结果，以及先前报道的燃烧振荡的放热区的轮廓的影响，意味着排气再循环的高压，高温湍流预混火焰是有效的抑制燃烧振荡的预混型燃气轮机燃烧室。
Turbulent premixed flames of mixtures of CH4and air diluted with CO2at high pressure and high temperature were experimentally studied to clarify the effects of exhaust gas recirculation (EGR), especially the effects of CO2in EGR gases, on turbulent flame characteristics. The maximum CO2dilution ratio, defined as the ratio of the molar fraction of CO2to those of air and CO2, was 0.1. The mixture was preheated up to 573K and the maximum pressure was 1.0MPa. Bunsen-type turbulent premixed flames of the mixtures were stabilized in a high-pressure chamber. OH-PLIF visualizations of the flames were performed. By analyzing the OH-PLIF images, turbulent burning velocity, mean volume of turbulent flame region, and mean fuel consumption rate were calculated. Results showed that the turbulent burning velocity, ST, normalized using laminar burning velocity, SL, became smaller when the mixture was diluted with CO2. When the turbulent flame region was defined as the region between 〈c〉=0.1 and 〈c〉=0.9, the mean volume of the flame region increased in the case of CO2dilution. Moreover, the mean fuel consumption rate in the flame region decreased with increasing CO2dilution ratio. This effect was stronger than the decrease in mass fraction of fuel due to CO2dilution. The decrease in the smallest wrinkling scale of the flame front with increasing turbulence Reynolds number in the case of CO2dilution was more significant than that in the case of no CO2dilution, corresponding well to the scale relation due to turbulence and intrinsic flame instability proposed previously. These results, as well as the previously reported effects of the profiles of the heat-release region on combustion oscillation, imply that exhaust gas recirculation for high-pressure, high-temperature turbulent premixed flames is effective for restraining combustion oscillation of premixed-type gas-turbine combustors.