对冲燃烧超临界锅炉气固两相流动数值模拟

Numerical Simulation of Gas-solid Two-phase Flowing in Opposed Firing Supercritical Boiler

为研究1 900 t/h超临界燃烧锅炉炉内气固两相流动问题,采用标准k-ε模型和DPM模型(离散相模型)对3种典型负荷下炉内流动特性和固体颗粒轨迹进行研究。研究结果表明:在不同典型负荷下前后墙射流均能形成稳定对称的流场,炉内气流扰动较强,有利于煤粉的燃烧燃尽;100%负荷下在炉膛四周产生漩涡,颗粒对水冷壁产生冲刷;炉内合适的煤粉粒径能够保证煤粉在炉内的停留时间。研究结果对锅炉的热态燃烧调整和效率的提高提供理论依据。

To study the flow characteristics in furnace of a 1 900 t/h opposed firing supercritical boiler,this paper carried out the corresponding numerical simulation under different load with standard k-ε model. The pulverized coal particle trajectories in furnace were described with DPM model. The study showed that the jets of burners can form a stable and symmetric flow field under different loads. Strong disturbance in the air flow inside furnace is beneficial to the burning of pulverized coal. Eddies appear on the wall under 100% load,and the particles erode furnace wall. The proper pulverized coal particle size can ensure the particle residence time in furnace.