富氧燃烧含灰烟气辐射特性的部分光谱k模型

Partial spectrum k-distribution model for radiative property of flue gas with soot and flyash from oxygen-enriched combustion

针对煤粉在富氧燃烧方式下烟气为炭黑、飞灰、高浓度CO2和H2O蒸气混合物的辐射换热问题,建立了描述混合物非灰辐射特性的部分光谱k分布模型。为了验证模型的有效性,以文献中煤粉在富氧燃烧方式下烟气生成状况为例,采用该模型与离散坐标法相结合的方法,计算了一维无限大平行平板、单光谱行程和二维矩形封闭系统内混合物的辐射源项和壁面热流量,并与逐线计算、全光谱k分布模型和宽带k分布模型的计算结果进行了比较。结果表明:所提出的部分光谱k分布模型与逐线计算的结果吻合较好;与文献报道的两个模型相比,计算精度有所提高,因此适用于富氧燃烧方式下含灰烟气辐射特性的计算。

A new larger pressure p air-fired boilers. partial spectrum k-distribution mo ath-lengths and possibly different del is developed for oxy-fired boilers, characterized by ratios of water vapor and carbon dioxide compared to In this model spectral regions with similar background properties are grouped into M partial spectrum distributions, in which the k distribution absorption coefficients of mixture are produced from multiplication approach. The absorption coefficients of gas are assembled from a narrow-band k- distribution database, but the scattering and absorption coefficients and phase function of particle are predicted by Mie theory. The radiation source and wall flux between two cold black parallel plates and for one signal spectral path and a two-dimensional rectangular system are calculated to verify the present model by combination of the present model and the discrete ordinate method in the furnace of flue gas with soot, flyash, high concentration of water vapor and carbon dioxide gas under oxygen-enriched coal combustion mode. The results from the present mode are more reasonably consistent with those by the line-by-line method. Moreover, the accuracy of the present model is higher and the computation time is reasonable compared with full-spectrum correlated-k distribution and wide band correlated-k model. It seems that this new partial spectrum k-distribution model is suitable for oxygen-enriched flue gas with flyash.