本文采用完全可压缩的N-S方程,对当量比为1.0的H_2/air旋流预混火焰进行了直接数值模拟研究。氢气和空气的化学反应采用9种组分19步的详细机理。模拟结果表明,强旋流流场中存在回流区,碗形旋流火焰稳定在回流区的外围。在火焰面上沿火焰法向提取了局部火焰结构,将局部湍流火焰结构与层流预混火焰的火焰结构进行了比较,发现局部湍流火焰比层流预混火焰更薄,燃烧强度更高。
Direct numerical simulation is employed to study a H_2/air swirling premixed flame with an equivalence ratio of 1.0 using the fully compressible N-S equation system.A 9 species 19-step reduced mechanism for hydrogen/air combustion is adopted.The result shows that a recirculation zone exist in the high swirling flow filed,around which the bowl shape flame is stabilized.The local flamelet structures are extracted randomly along the flame front and compared with the corresponding laminar flame structure.It is shown that the local flamelet is thinner than the laminar flame,and the combustion is more intensive in the local flamelet than in the laminar flame.