论文部分内容阅读
电站锅炉系统中,换热器表面的积灰结渣过程关系到机组的安全及高效运行。积灰的光谱发射率是影响高温烟气与积灰之间辐射换热的重要参数。基于双通量方程和相关散射修正,建立了积灰光谱发射率的理论模型,计算2种积灰样品的光谱发射率,计算结果与实验值吻合。在此基础之上,讨论了波长、颗粒粒径和化学成分对积灰光谱发射率的影响。积灰发射率在4μm以下非常小;在4~6μm,发射率显著增大;6μm以上发射率趋于稳定。积灰光谱发射率随着颗粒粒径以及氧化铁含量的增大而增大。颗粒粒径以及氧化铁含量对积灰发射率的影响在5μm以下较为显著。
In power plant boiler system, the process of fouling and slagging on the heat exchanger surface is related to the safe and efficient operation of the unit. Fouling spectral emissivity is an important parameter that affects radiative heat transfer between high temperature flue gas and fouling. Based on the two-flux equation and the correlative scattering correction, a theoretical model of the emissivity of the fouling spectrum was established and the spectral emissivity of the two fouling samples was calculated. The calculated results are consistent with the experimental values. On this basis, the effects of wavelength, particle size and chemical composition on the emissivity of the ashes were discussed. The fouling emissivity is very small below 4μm; at 4 ~ 6μm, the emissivity increases significantly; and the emissivity above 6μm tends to be stable. Fouling spectral emissivity increases with increasing particle size and iron oxide content. The effect of particle size and iron oxide content on fouling emissivity is significant below 5μm.