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对一台1000MW超超临界机组双切圆锅炉的燃烧过程进行数值模拟,分析过量空气系数、AA风率、燃烧器投运方式及锅炉负荷等因素对NO排放的影响特性。计算与分析结果表明:燃烧过程中,炉膛内形成2个旋向相反的椭圆形流场。在炉膛下部,温度场与流场表现出很好的协同性。随着高度的增加,温度场与流场的协同性不断减弱;根据NO浓度沿炉高方向的变化规律,可以将炉膛沿炉高分为浓度迅速升高、浓度迅速下降和浓度缓慢上升3个区段;过量空气系数越小,NO排放越少;AA风率越高,炉膛出口NO排放越少;燃烧器的投运方式是影响NO生成的一个关键因素,在各负荷下,与投入上部燃烧器相比,投入下部燃烧器时NO排放量少。
The combustion process of a double-tangentially fired boiler for a 1000MW ultra-supercritical unit was numerically simulated and the influence of excess air ratio, AA wind rate, burner operating mode and boiler load on NO emission was analyzed. The results of calculation and analysis show that during the combustion process, two elliptical flow fields with opposite directions are formed in the furnace. In the lower part of the furnace, the temperature and flow fields show good synergy. With the increase of height, the synergy between temperature field and flow field is declining. According to the variation rule of NO concentration along the furnace height, the furnace can be divided into high concentration, high concentration, rapid decrease and concentration slowly increase 3 Section; the smaller the excess air ratio, the less the NO emissions; the higher the AA air rate, the less the NO emissions from the furnace exit; the mode of operation of the burner is a key factor that affects the NO generation. Under each load, Compared to the burner, when the lower burner into the NO emissions less.