摘要
利用Fluent软件对1台900 MW四角切圆燃烧锅炉在不同负荷下炉内燃烧过程进行了数值模拟,分析了负荷变化对炉内流动和传热的影响规律.结果表明：在高负荷工况下运行时,炉内燃烧充分且稳定,但是炉内火焰更容易冲刷水冷壁,可能发生局部结渣现象;在低负荷工况下运行时,炉内火焰充满度较差,切圆燃烧的稳定性显著下降,炉膛水冷壁灰污表面温度也相应降低,水冷壁表面结渣的倾向弱化,沿高度方向水冷壁吸热不均匀性增大.由于该锅炉的低NOx燃烧器采用了分离燃尽风,使得高温区扩展,火焰中心高度比采用有关标准推荐的方法计算所得结果高4-5 m.
The combustion process in a 900 MW tangentially fired supercritical boiler at different loads was simulated with Fluent to investigate the influence of boiler load on the flow and heat transfer in the furnace.The results showed that the combustion was stable and the combustion gas fully filled the furnace under high loads,but the flame would impinge the water wall and result in local slagging.When it was seriously reduced to the lower load,the flame fullness and the combustion stability decreased,while the temperature and the slagging tendency in the outer surface of ash layer on the water wall was lower.The non-uniformity of the heat flux in the height direction increased.The high temperature zone was enlarged due to the adoption of separated over fire air in the low NOx burners,which caused that the height of flame center was 4~5 m higher than the calculated results.
出处
《能源研究与信息》
2015年第4期220-226,共7页
Energy Research and Information
关键词
超临界锅炉
燃烧
数值模拟
锅炉负荷
supercritical boiler
combustion
numerical simulation
boiler load
