A new low NO_x burner for gas boiler is designed. A hollow tube is embedded in the burner axial center line, which is combined with the flared flame stabilizer to draw back the internal flue gas from inside the boiler, and a flue gas recirculation tube is installed outside the boiler to draw back the flue gas from the end of the boiler. The effectiveness of the burner is evaluated by industry experiments and extensive computational fluid dynamics (CFD) simulations. The research results show that the excess air ratio and external flue gas recirculation (e-FGR) rate significantly alter the temperature distribution and NO_x emission of the boiler. The temperature and NO_x emission do not vary monotonically with the excess air ratios, but decrease monotonically with the e-FGR rates. To achieve the low NO emission, the optimum excess air coefficient α should be 1.15 due to the better temperature uniformity, and the value of e-FGR rate should be in the range of 28%–40%. In addition, the maximum concentration of NO does not appear on the flame surface, but in the downstream region of the flame.

设计了一种新的燃气锅炉低NO _x燃烧器。燃烧器轴向中心线内嵌有一根空心管，该空心管与喇叭形火焰稳定器结合在一起，从锅炉内部抽回内部烟气，锅炉外部安装了烟气再循环管，从锅炉内抽回烟气。锅炉的末端。燃烧器的有效性通过工业实验和广泛的计算流体动力学（CFD）模拟进行评估。研究结果表明，过量空气系数和外部烟气再循环（E-FGR）速率显著改变的温度分布和NO _X锅炉的排放。温度和NO _x排放不会随过量空气比率单调变化，而是随着e-FGR速率单调减少。为实现低NO排放，由于更好的温度均匀性，最佳过量空气系数α应为1.15，e-FGR率的值应在28％–40％的范围内。另外，NO的最大浓度没有出现在火焰表面上，而是出现在火焰的下游区域。