【摘要】 针对燃烧模拟中颗粒辐射特性精确度不高、燃煤锅炉辐射特性计算十分复杂的问题，建立了一种新的单颗粒煤粉燃尽模型，该模型拟合了多煤种随燃尽率变化的密度比和直径比．以焦作煤为例，利用Mie理论计算了煤颗粒的吸收、散射效率，进一步考虑煤粉粒子群计算了吸收、散射系数．以此为基础，通过用户自定义函数(UDF)将模拟中颗粒发射率和散射因子分别修正为多项式模型和线性模型，与现场检测结果比较验证，研究了随燃尽率变化的燃煤锅炉辐射特性．结果表明：各煤种燃尽过程中密度变化较大，完全燃尽时粒径缩小至50%～70%．颗粒发射率在燃尽前中期从0.897开始略微上升，末期急剧下降．上述修正后与现场断面温度检测的误差从6.07%下降至2.96%，与实际情况更加吻合．更多还原

【Abstract】 To address the issues of low accuracy in particle radiation characteristics in combustion simulation and complex calculation of radiation characteristics in coal-fired boilers,a new single particle pulverized coal burnout model is established. This model fits the density ratio and diameter ratio of multiple coal types varying with burnout rate. Taking Jiaozuo coal as an example,the Mie theory is used to calculate the absorption and scattering efficiency of coal particles. With further consideration of pulverized coal particle swarm,the absorption and scattering coefficients are calculated. Based on this,the particle emissivity and scattering factor in the simulation are modified into polynomial and linear models using user-defined functions(UDF),which is compared and verified with on-site detection results. The radiation characteristics of coal-fired boilers varying with burnout rate are studied. The results show that there is a significant change in density during the combustion process of each coal type,and the particle size decreases to 50%—70% when fully burned. The particle emissivity slightly increases from 0.897 in the early and mid-term of combustion,and sharply decreases in the late stage. The error between the above correction and the on-site section temperature detection decreases from 6.07% to 2.96%,which is more consistent with the actual situation.更多还原