Numerical simulation of combustion characteristics in a multi-point lean direct injection combustor

A numerical investigation was conducted to study the combustion characteristics in a five-point lean direct injection combustor. The influence of the pilot's swirl number to the combustion characteristics at both idle and takeoff conditions was carried out. The simulation results show that the radial dimension of the central recirculation zone without-reaction is lower than under-reaction at idle condition; but at takeoff condition, there're few distinctions on the structure of the central recirculation zone between the flow fields under-reaction and without-reaction. With the increasing of the pilot's swirl number, the radial dimension of the central recirculation zone increases. The temperature distributions of the center section are different because of the mutual interferences of the pilot and main stage. And with the increasing of the pilot's swirl number, the NO x emissions of the exit of the combustor increases. 针对五点贫油直接喷射单管燃烧室燃烧性能开展数值模拟研究, 研究副模旋流强度对慢车和起飞工况下燃烧室燃烧性能的影响。计算结果表明: 慢车工况下燃烧室热态中心回流区径向尺寸较冷态工况增大, 起飞工况下冷热态中心回流区结构形态接近; 随着副模旋流强度增大, 燃烧室中心回流区径向尺寸也增大, 并且由于主副模流动之间的相互影响, 不同副模旋流强度下燃烧室内温度分布存在差异; 燃烧室中心截面NO x 分布与温度场分布相同, 燃烧室内NO x 热力学生成机理占主要地位; 随着副模旋流强度增强, 燃烧室出口NO x 排放也增大。