燃气轮机燃料轴向分级燃烧室的数值分析

为改善燃气轮机燃烧室的火焰筒壁温较高以及污染物排放等问题,提出了在火焰筒的壁面增加二次燃料喷口的轴向分级燃烧模式。利用ANSYS CFX软件并根据化学反应机理计算和分析了燃气轮机轴向分级燃烧室的流场和温度场,并与非分级燃烧室的结果进行了比较。结果表明:增大二次燃料比例可以使火焰筒壁面温度降低、出口污染物质量分数及出口不均匀系数减小,但出口平均温度会随之降低,导致做功能力减小。过量空气系数会影响火焰筒壁温、出口平均温度与NO质量分数。合理的二次燃料比例区间取决于多个条件。

Numerical analysis of gas turbine combustor with axially-staged fuel feed

Axially-staged combustion was proposed by feeding secondary fuel into the combustor in order to improve the high wall temperature and pollutant emmission in a gas turbine combustor. With detailed chemical kinetic mechanism, the flow field and temperature field of the axially-staged combustor in a gas turbine were calculated and analyzed using ANSYS CFX software, which were comparied with those of the non-staged combustior. It was found that the wall temperature of flame tube, the mass fraction of outlet pollutant and the uneven coefficient of outlet temperature decreased with the increase of secondary fuel ratio. However, the average outlet temperature decreased as well, which resulted in the decline of work capacity. In addition, the results showed that the excess air coefficient affected the wall temperature of flame tube, the average outlet temperature and the mass fraction of NO. Therefore, the range concerning the appropriate secondary fuel ratio depended on several conditions.