浓缩环对旋流燃烧器NO_x生成影响的数值模拟

Numerical Study of the Influence of Concentration Rings on the Formation of NO_x Produced By Swirl Burners

运用Fluent软件对中心给粉旋流燃烧器进行了燃烧数值模拟,探讨了浓缩环对燃烧器NOx生成的影响,分析了燃烧器燃烧时的温度场、氧浓度场以及包含热力NOx、燃料NOx和快速NOx在内的NOx浓度场,比较了不同浓缩环结构下燃烧器出口沿轴向方向NOx浓度曲线。模拟结果表明:浓缩环可降低旋流燃烧器的NOx生成量100～200 mg/m3,NOx的排放量也相应降低;调节浓缩环距端口距离和调节浓缩环间距,亦可降低燃烧器的NOx排放量,两者调节的最佳值分别为325 mm和80 mm。

By using the CFD software Fluent,a combustion numerical simulation was performed of a centrally-fed pulverized coal swirl burner.In this connection,the influence of the concentration rings on the formation of NOx produced by the burner was investigated,the temperature field,oxygen concentration field and NOx concentration field,including thermal NOx,fuel NOx and prompt NOx,were analyzed when the burner was in its combustion and the NOx concentration curves along the axial direction at various concentration ring configurations were compared.The simulation results show that the concentration rings can lower the NOx production capacity of the burner by 100~200 mg/m3.To adjust both distance of the concentration rings to the port and their intervals can reduce NOx emissions of the burner,optimum values of which are 325 mm and 80 mm respectively.