等离子燃烧器燃烧特性的数值模拟

Numerical Simulation of Combustion Characteristics of Burners with Plasma Ignition

结合煤粉锅炉等离子燃烧器的结构特点,用数值仿真软件Fluent对套筒式等离子燃烧器的内燃特性进行了二维流动数值模拟,计算了一次风从燃烧器的等离子点火区到炉膛内的燃烧特性,并与实验和工程应用结果进行了比较。模拟结果表明:在等离子燃烧器喷口形成了“粉包火”的着火工况,降低了燃烧器喷口温度,改善了燃烧器的工作环境。该燃烧模拟结果与等离子燃烧器在某600MW机组现场应用以及在等离子热态试验台点火试验的结果基本吻合。

In connection with structural features of plasma igniting burners of pulverized coal fired boiles, with the help of software Fluent, a two-dimensional numerical flow field simulation, for disclosing the internal combustion characteristics of a sleeve type plasma igniting burner, has been performed. The scope of calculation extended form the entry of primary air in the ignition zone up to the furnace, and results were compared with experimental observations and practical applications. Simulation results show that the powder envelop, around the plasma burnet＇ s nozzle, reduces its temperature and improves the burner＇s working condition. Simultaneously, the sleeve like structure with stepped ignition allows part of the coal powder to be pushed out of the burner and be burned in the furnace, so that the inner and outer sleeve form a cocentric double-layer duct, rewith the velocity in the inner sleeve being reduced, which is advantageous for ignition and burn out of the coal powder. Simulation results basically agree with observations made on a 600 MW unit and those of ignition tests performed on a hot plasma test rig. Figs 6, tables 2 and refs 3.