高炉内煤粉燃烧速度场的数值模拟

文章利用商业软件FLUENT,采用有限体积法建立了高炉内回旋区煤粉燃烧三维数学模型。在不同煤比和不同富氧率下,分析研究了煤粉燃烧过程的速度场、颗粒轨迹。模拟结果表明:采用动量方程、标准双方程湍流模型、离散相模型对高炉回旋区煤粉运动过程进行数值模拟,结果是合理的、可信的。喷煤量对煤粉颗粒运动过程气体的运动速度影响比较明显,对漩涡内的气体速度影响不是很明显。煤粉颗粒运动过程气体的运动速度随着富氧率的增加而有所增加,卷入漩涡的煤粉颗粒并不是随着富氧率的增加而增加。只有卷入漩涡的颗粒越多,越有利于煤粉的燃烧。富氧率对煤粉燃烧过程的有利影响随着富氧率的增加出现拐点,表明富氧率应该维持在一个合适的水平,并不是越高越好。

Numerical Simulation for Velocity Field of Pulverized Coal Combustion in Blast Furnace

In the paper, the 3 D mathematical model for pulverized coal combustion in the raceway of blast furnace is es- tablished with finite volume method and commercial software FLUENT. Wth different coal ratios and oxygen ratios, the veloc- ity field and track of particle in the process of pulverized coal combustion are analyzed and studied. The simulated results in- dicate that the results with momentum equation, standard double- equation turbulence model and discrete phase model are reasonable and reliable. The effect of coal injection quantity on velocity of movement for air in the movement of pulverized coal particle is more obvious, but not obvious on the velocity of gas in vortex. The velocity of movement for air in the move- ment of pulverized coal particle is increased with the increase of oxygen ratio, while tile pulverized coal particle involved in vortex is not increased with the increase of oxygen ratio. The more particle involved in vortex, the better for pulverized coal combustion;the positive effects of oxygen ratio on pulverized coal combustion may contribute to point of inflection with the increase of oxygen ratio,which indicates that the oxygen ratio should be kept at a suitable level, not the higher, the better.