应用改进的移动火焰锋面(MFF)模型对碳粒燃烧的能量分配系数进行了研究,得到了考虑CO在颗粒边界层内燃烧及CO2发生表面还原反应的能量分配系数表达式.在一实际煤粉火焰条件下,计算了可在单膜(SF)模型中直接应用的可比能量分配系数,并与传统SF模型的取用值进行了比较.计算结果表明,碳粒直径越小,平均能量分配系数越大;随着碳粒温度的升高,能量分配系数下降.在本文的计算条件下,平均能量分配系数约为0.7,平均可比能量分配系数值高于0.5,远大于传统单膜模型(SF-CO)计算的可比能量分配系数0.3.
The energy distribution coefficient (Xo) in combustion of char particles was studied by using the improved moving flame front (MFF) model. The energy distribution coefficient considering the homogeneous oxidation of CO and the surface reduction of CO2 was derived explicitly. Under a practical pulverized coal flame condition, the comparable energy distribution coefficient was calculated and compared with the value used in the traditional single film (SF-CO) model. The calculated results show that the smaller the particle diameter, the greater the energy distribution coefficient is. With the increase of the particle temperature, the energy distribution coefficient decreases. Under the calculation condition, the averaged energy distribution coefficient is about 0.7, and the averaged comparable energy distribution coefficient value is over 0.5 ,which is much higher than 0.3 obtained by the traditional single film (SF-CO) model.