煤粉低尘燃烧器内燃烧特性的数值模拟

介绍了一种用于中小型工业窑炉的新型煤粉低尘燃烧技术，利用计算机数值模拟考察了煤粉低尘旋流燃烧器的特性. 在合理选择气相流动、固相流动、煤燃烧及NO的生成等模型的同时，针对旋流燃烧场中固体颗粒在壁面附近的碰撞及熔融特性，探讨了煤粉在壁面处的运动模型，并以此为基础考察了燃烧场的两相流动特性，模拟了燃烧器内煤粉的燃烧过程及各物理量的分布. 在与实验比较的基础上，对燃烧器的结构进行了改进. 结果表明，在低化学计量比下，改进后的燃烧器性能更好，颗粒在燃烧器内充分燃尽，在保证液排渣效果的同时，NO的排放远低于常规液排渣旋风器的NO排放量.

Numerical Simulation of Burning Characteristics of the Novel Low-dust Slagging Combustor of Pulverized Coal

The technology of pulverized coal low-dust slagging combustion, which is most suitable to small industrial furnaces, was introduced. Numerical method was used to simulate the burning characteristics of a f400 mm combustor. In addition to selecting several proper models for gaseous flow, solid phase flow, coal combustion and NO emission, the behavior of coal particles near the wall was discussed. Based on these models, the two-phase flow and combustion characteristics in the combustor were analyzed in detail. The predicted temperatures and NO concentrations were compared with the experimental data from the combustor, and acceptable agreement was achieved. Based on the experimental data and computational analysis, the old slag combustor was modified because of some defects. The recent experimental results proved that the performance of the new combustor was much superior to old one at low stoichiometric ratio, offering the advantages of high carbon burning efficiency, not very high temperature at the rear of combustor, high slag-capturing efficiency and low NO emission. When stoichiometric ratio is about 0.8, NO concentration at the rear of combustor is about 400 mg/Nm3, which is much less than that in conventional cyclone combustors.