ODPP/OESC旋流火焰的试验与模拟研究

Experimental and simulation study of ODPP/OESC swirl flame

利用三维旋流燃烧系统,对稀氧部分预混/富氧补燃(ODPP/OESC)火焰结构和污染物生成特性进行了试验研究,降低稀氧体积分数、提高富氧体积分数,动力火焰呈现轴向拉伸趋势,而扩散火焰长度则逐渐缩短;同时,动力燃烧区和扩散燃烧区温度逐渐降低,NO_x排放量显著下降,CO排放量则有所提高。相同工况下数值模拟结果显示,ODPP/OESC改变了动力燃烧区的NO_x生成机理,是NO_x排放量降低的根本原因。ODPP/OESC基于燃料/氧化剂空间体积分数分布的物理过程控制,有效均衡了动力燃烧区与扩散燃烧区的反应速率,可实现CO与NO_x排放的平衡控制。

A three-dimensional swirl experimental diagnostic system was constructed. The flame structure and emission characteristics of oxygen diluted partially premixed/oxygen enriched supplemented combustion （ODPP/OESC） were explored. With the decreasing of oxygen-diluted concentration and increasing of oxygen-enriched concentration, dynamic flame is elongated in axial and diffusion flame is gradually shortened, with both decreased temperature. Meanwhile NOx emission is reduced a lot while CO emission is increased. The simulation results with the same conditions show that ODPP/OESC changes the NOx formation mechanism, which is the main cause for lower NOx emission. By controlling the physical process of the fuel/oxidant concentration distribution of ODPP/OESC, the reaction rate of dynamic flame and diffusion flame could be balanced and CO/NOx emissions could be controlled.