超临界循环流化床锅炉二次风射程的数值模拟研究

Numerical Simulation of Secondary Air Penetration Depth in Supercrtical CFB Boiler

针对超临界循环流化床锅炉的二次风穿透性问题,应用欧拉-欧拉双流体模型,对该大型炉膛进行数值模拟计算,研究主气流流速、二次风射流速度、颗粒背景和二次风射流角度对二次风射程的影响。结果表明,二次风射程随二次风射流速度的增大而增大,随主气流流速和背景颗粒浓度的增大而减小,同时,二次风射流角度对二次风射程也有一定的影响。二次风射程不足是循环流化床锅炉的大型化过程中的重要问题,本模拟结果具有一定理论价值,为大型循环流化床锅炉的设计和优化提供理论指导。

Aiming at the problem of the secondary air penetration depth in supercritical CFB（Circulating Fluidized Bed） boilers, numerical simulation was carried out for the furnace of a supercritical circulating fluidized bed boiler by use of the Eulerian-Eulerian model. The influence of following factors on secondary air penetration were studied, such as primary air velocity, secondary air jet velocity, background particle parameters and secondary air jet angle. Results show that the secondary air jet penetration is proportional to secondary air velocity, inversely proportional to primary air velocity and background particle concentration. Meanwhile, the secondary air jet angle also has a certain influence on the secondary air penetration. The secondary air penetration deficiency is an important problem in the process of large-scale CFB boiler, results of this simulation has a certain theoretical value, which provides theoretical guidance for the design and optimization of large CFB boilers.