冷却边界下变孔隙多孔介质燃烧特性研究

针对天然气等高热值气体燃烧氮氧化物排放高和多孔介质烧蚀问题，设计开发了变孔隙多孔介质燃烧试验系统，研究了不同燃烧器内芯结构的孔隙排列方式及冷却空气流量对燃烧温度及污染物排放的影响。结果表明：积木式结构外环孔密度呈阶梯状排列比呈均匀型排列更有利于热量沿燃烧器径向传递；积木式结构的内芯孔密度呈阶梯状排列时，有利于提高燃烧室下游的温度；随着冷却空气流量的增大，冷却空气吸热量所占燃烧放热量的比例由23.62%增至70.87%，尾部烟气带走热量占燃烧放热量比例由71.65%降至21.63%，CO排放升高，NO排放最低降至3mg/m3。

Study on combustion characteristics of porous media with variable porosity under cooling boundary

Aiming at the problems of high NOx emission and erosion of porous media during combustion of high calorific value gases such as natural gas, a variable porosity porous media combustion test system was designed and developed. The effects of pore arrangement and cooling air flow rate on combustion temperature and pollutant emission were studied. The results show that the pore density of the outer ring of the building block structure is more conducive to the heat transfer along the radial direction of the burner than the uniform arrangement. When the pore density of the inner core of the building block structure is arranged in a stepwise, it is beneficial to increase the downstream temperature of the combustion chamber. With the increase of cooling air flow rate, the proportion of heat absorbed by cooling air in combustion heat release increased from 23.62% to 70.87%, the proportion of heat carried away by tail gas in combustion heat release decreased from 71.65% to 21.63%, CO emission increased, and NO emission decreased to 3mg/Nm3.