摘要
使用可实现k-ε双方程模型,对600 MW超临界锅炉低NOx轴向旋流燃烧器(low NOx axial swirl burner,LNASB)燃烧过程进行了数值模拟,研究了二次风量及旋流强度对燃烧器热态流场、温度场分布的影响,对燃烧器拟改进方案进行了比较。数值模拟结果表明,内二次风对回流区影响较大,外二次风对扩展角影响明显,增大中心风速可以增加回流区根部距离;内二次风旋流强度及风量过大时容易引起火焰偏斜贴壁,中心风退出后燃烧器喷口处温度上升明显,中心给粉可以有效地增加火焰离喷口距离,为最佳改进方案。与试验结果进行对比,获得了比较一致的结果。通过设备改进和燃烧调整,解决了锅炉长期以来的恶性结渣问题,为LNASB燃烧器设计和运行提供了一定的防结渣理论基础。
The combustion process of low NOx axial swirl burner（LNASB） was numerically studied in a 600 MW supercritical boiler with realizable k-e model.The influence of secondary air flow and swirling intensity on the flow field and the distribution of temperature were studied.the different modification project of the burner was compared.The numerical simulation results had shown that the recirculation zone is hardly affected by the inner secondary air.The extended corner was impacted obviously by the external secondary air.Increasing the velocity of central air could enlarge the root distance of the recirculation zone.Increasing the flow and swirling intensity of the secondary air could make the flame deviation and adherence.The temperature nearby the burner nozzle increased significantly after turning off the center air.The best project is centrally fuel rich which could increase the distance between flame and nozzle.The comparison between the measured values and predicted results shows good agreement.By improving burners and adjusting combustion can settle the problem of malignant coking,it can provide some theoretical basis for the LNASB burner.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2011年第2期15-21,共7页
Proceedings of the CSEE
