In this paper, the compound heat transfer of convection and radiation in an internal circulating fluidized bed for low temperature oxidation of pulverized coal was numerically simulated. The numerical prediction about the compound heat transfer characteristics and its relationship of convection and radiation was compared with the experimental measurements of low temperature radiation. The discrete ordinate model (DOM) was employed to investigate the radiation heat transfer in the low temperature oxidation internally fluidized bed, and user-defined function (UDF) was compiled by considering the effect of the particle flow emissivity on radiation heat transfer. The convection heat transfer coefficient increases with the increase of gas inlet volume flow rate and initial bed material height, however, thermal radiation coefficient was opposite. An increase of the thermal flux results in an increase of the surface temperature of the fluid and the heater surface, and the thermal transfer coefficient between bed material and heater surface is also increased. The results have the application reference to complex thermal transfer design of circulating fluidized bed systems wherein thermal radiation transfer must be considered as a significant mode.

数值模拟了内部循环流化床中煤粉低温氧化过程中对流和辐射的复合传热。将复合传热特性及其对流与辐射关系的数值预测结果与低温辐射的实验测量结果进行了比较。利用离散纵坐标模型（DOM）研究了低温氧化内部流化床中的辐射传热，并考虑了粒子流发射率对辐射传热的影响，编制了用户定义函数（UDF）。对流换热系数随进气口体积流量和初始床料高度的增加而增加，但热辐射系数却相反。热通量的增加导致流体和加热器表面的表面温度增加，并且床材料与加热器表面之间的热传递系数也增加。该结果对循环流化床系统的复杂热传递设计具有应用参考，其中必须将热辐射传递视为重要模式。