基于灰层累积的焦炭燃烧缩核模型FLUENT数值模拟研究

FLUENT numerical simulation of coke combustion shrinkage model based on accumulation of ash layer

ANSYS FLUENT提供的焦炭燃烧模型中,忽略了碳粒燃烧过程中灰层累积的影响,导致模拟焦炭燃烧速率偏大。为此,基于FLUENT原始模型,结合碳粒燃烧过程中灰层积累对燃烧的抑制原理,利用FLUENT中User Defined Functions(UDF)模块,提出一种基于灰层累积的焦炭燃烧缩核数学模型,称为"基于灰层累积的动力/扩散控制"燃烧模型。计算结果表明:相比于原始模型,改进模型中炉膛速度与温度分布更符合热力计算值;模拟得到的飞灰含碳量与实际测值基本一致,说明改进模型更加合理,且模拟结果相对准确。

In the coke combustion model provided by ANSYS FLUENT, the influence of the accumulation of ash layer during the combustion of carbon particles is neglected, resulting in a large burning rate of coke. Therefore, based on the original FLUENT model, combined with the suppression principle of ash accumulation in the combustion process of carbon particles, a mathematical model of coke combustion reduction considering the accumulation of gray layer is proposed by using the User Defined Functions(UDF) module in FLUENT. It is called the "dynamic/diffusion control based on the accumulation of gray layers" combustion model. The calculation results show that compared with the original model, the furnace velocity and temperature distribution in the improvement model are more in line with the thermal calculation value. The simulated carbon content of the fly ash is consistent with the actual measured value, indicating that the improvement model is more reasonable and the simulation results are relatively accurate.