In this study, banded one gas spectral line-based weighted sum of grey gases (banded SLW-1) model is coupled with a 3-D radiation code based on method of lines (MOL) solution of discrete ordinates method (DOM) for freeboard of METU 0.3 MW_t atmospheric bubbling fluidized bed combustion (ABFBC) test rig containing non-gray gas, non-gray particle mixture bounded by non-gray walls. Spectral parameters of banded SLW-1 are estimated by the approach based on two emissivities calculated at two different path lengths L₁ and L₂. The predictive accuracy of banded SLW-1 model is tested by comparing its incident wall heat flux and source term predictions with measurements and predictions of banded SLW. The results indicate that band-wise selection of L₁ and L₂ based on spectrally averaged mean beam length provides the most accurate radiative heat transfer predictions. Furthermore, based on a sensitivity analysis on the test rig under consideration, utilization of path lengths L₁ and L₂ which are 0.10 and 1.10 times of the spectrally dependent mean beam length is found to yield the best radiative heat transfer predictions in terms of accuracy. Incident heat flux and source term predictions of banded SLW-1 are found to be in reasonable agreement with those of banded SLW under both air and oxy-fired conditions. Furthermore, CPU time requirement of banded SLW-1 is about 20-25 times lower than that of banded SLW. With the introduction of fly ash recycling, particle load increases an order of magnitude leading to further improvement in the accuracy of banded SLW-1. On the other hand, gray wall assumption leads to accurate radiative heat flux predictions whereas this assumption leads to considerable inaccuracies in the source term predictions in the upper region of freeboard. However, those inaccuracies become insignificant with the introduction of fly ash recycling. Application of the model to different wall conditions common in the industry indicates that discrepancies between the source term predictions of gray and non-gray cold water wall and those of gray and non-gray cold slag covered water wall are insignificant for the combustion test rig under consideration which is attributed to the combined effects of low wall temperatures and similar gray and non-gray wall emissivities.

在这项研究中，基于带状气体光谱线的灰色气体加权总和（带状SLW-1）模型与基于干线离散坐标法（DOM）的线法（MOL）解的3-D辐射代码结合的METU 0.3 MW _t大气鼓泡流化床燃烧（ABFBC）试验装置包含以非灰色壁为边界的非灰色气体，非灰色颗粒混合物。通过该方法，基于在两个不同路径长度L ₁和L ₂处计算出的两个发射率，估计带状SLW-1的光谱参数。通过将带状SLW-1模型的入射壁热通量和源项预测与带状SLW的测量和预测进行比较，来测试带状SLW-1模型的预测准确性。结果表明，L _1的带状选择基于频谱平均平均光束长度的L ₂和L ₂提供了最准确的辐射传热预测。此外，基于对所考虑的测试装置的敏感性分析，可利用路径长度L ₁和L ₂发现它们是光谱相关平均光束长度的0.10倍和1.10倍，就准确度而言，它们可得出最佳的辐射传热预测。发现带状SLW-1在空气和氧气燃烧条件下的入射热通量和源项预测与带状SLW的合理一致。此外，带状SLW-1的CPU时间要求比带状SLW的CPU时间要求低约20-25倍。随着粉煤灰循环利用的引入，颗粒载荷增加了一个数量级，从而进一步提高了带状SLW-1的精度。另一方面，灰墙假设导致精确的辐射热通量预测，而此假设导致在干舷上部区域的源项预测中存在相当大的误差。然而，随着粉煤灰回收的采用，这些不准确的地方变得微不足道了。该模型在行业中常见的不同壁面条件下的应用表明，灰色和非灰色冷水壁的源项预测与灰色和非灰色冷渣覆盖水壁的源项预测之间的差异对于在以下条件下的燃烧试验台来说是微不足道的考虑归因于低壁温以及类似的灰色和非灰色壁面发射率的综合影响。