回转窑内煤粉燃烧的数值模拟

Numerical Simulation of Coal Combustion in a Rotary Kiln

针对一实际回转窑建立模型进行了煤粉燃烧的数值模拟,其中气相采用k-ε双方程湍流模型、离散相采用颗粒轨道模型、燃烧采用非预混燃烧结合简化的PDF模型、辐射采用P1模型。模拟结果表明:在整个窑长方向,流场由"双峰"结构逐渐向"单峰"结构转化;一次风射流对二次风的卷吸作用很明显,形成了内回流区和外回流区。火焰形状呈棒槌形,但燃烧器附近低温区很长,需要改进。

Numerical simulation of coal combustion was carried out aiming at a true rotary kiln. The gas phase was expressed with κ-ε two-equation model; the combustion was described with non-prcmixed model; the radiation was expressed with P1 radiation model. The numerical simulation results show that along the length of the whole kiln, the velocity field looks like double-humped type at first, and then change to single-humped type. there is strong entrainment from the primary air to the secondary air, resulting in inside reeirculation zone and outside recirculation zone. The flame looks like wooden club shape, however, there is long low temperature region near the burner, which should be improved.