燃油低氮燃烧器的大涡模拟

Large Eddy Simulation of Low NOx Oil-fired Burner

对采用烟气再循环的旋流非预混燃油低氮燃烧器开展了数值模拟,在相似性原理的基础上分析了各相似特性及准则数,确定十分之一缩尺模型与原模型的湍流燃烧过程相似且保证燃尽。对模型进行最小贯通时间和收敛性研究,分析了运行工况下燃烧器温度、速度、NO排放、涡与火焰等特性。燃烧器在模拟工况下表现出较好的燃尽特性,炉膛中能较好地展示燃烧不稳定及火焰面的拉伸扭曲现象,同时保证了NO排放浓度低于50 mg/m^(3)(标态)(O_(2)=3.5%)。

The computational fluid dynamic(CFD)software FLUENT was used to simulate the swirl non-premixed fuel low nitrogen burner with flue gas circulation. Based on the similarity principle, the similarity characteristics and similarity number were analyzed, and the one-tenth scale model was confirmed to be similar to the original model and burnt in turbulent combustion process. The minimum penetration time and convergence of the model were studied, and the characteristics of burner temperature, velocity, NOemission, vortex and flame were analyzed under operating conditions. The burner showed good burnout characteristics under simulated conditions, and the combustion instability and the tensile distortion of flame surface could be well displayed in the furnace, and assureed that the emission of NOis less than 50 mg/m^(3)(O_(2)=3.5%).