煤粉粒子的发射率

The Emissivity of Pulverized Coal Particles

本文基于均质光滑球形粒子散射的Ｌｏｒｅｎｔｚ－Ｍｉｅ电磁理论，利用实验测得的煤粉粒子的复折射率，计算了国产二十种动力煤煤粉粒子的发射率。计算结果表明，煤粉粒子的全波长发射率与粒径、粒子温度及煤种有关，并在很宽的粒径范围内远远偏离文献中常用的假定值０．８，粒径在１－２０μｍ范围内煤粉粒子的发射率常常大于１．０。本文解释了部分煤粒子发射率大于１．０的原因及其物理含义，并给出了国产二十种动力煤煤粉粒子发射率随粒径、温度变化的线算图。

On the basis of the classical Lorentz Mie electromagnetic theory for isotropic and homogeneous spherical particles and by utilizing the experimentally measured complex refractive indices of pulverized coal particles determined are the emissivity of pulverized coal particles of twenty kinds of Chinese coals for power generation The results of calculation show that the full wave length emissivity of pulverized coal particles is dependent on particle diameter,particle temperature and coal type and within a wide range of particle diameters radically deviates from the assumed value of 0 8 often given in technical literature It has also been found that within a particle diameter range of 1-20 μm the emissivity of the pulverized coal particles is often greater than 1 0 The reason why some pulverized coal particles have an emissivity greater than 1 0 is given with an explanation of its physical meaning For engineering calculation purposes the curves showing the variation of emissivity with particle diameter and temperature are given for twenty kinds of typical Chinese coals