中文摘要：

在大型电站燃煤锅炉中，辐射是最主要的换热方式，研究煤粉燃烧火焰的黑度（辐射率）对炉内的辐射传热计算有着非常重要的作用。该文提出用彩色摄像机的RGB函数测量火焰黑度。当用彩色CCD摄像机摄取煤粉炉内火焰辐射图像时，实际上获得的是红、绿、蓝三基色波长下的单色辐射图像。基于Wien辐射定律和辐射图像处理技术可以从3幅单色辐射图像中检测到燃粉锅炉中火焰的黑度。该检测方法用黑体炉进行标定。在3种负荷工况下，对两台燃煤锅炉的检测结果表明：沿炉膛高度方向，燃烧器区域的火焰黑度最大，炉膛上部的火焰黑度较小；灰份含量较高的煤，其燃烧火焰黑度较大：当负荷变大时，火焰黑度也随之增加。

英文摘要：

Radiation is the predominant mode heat transfer in coal-fired furnaces. The research of flame emissivity is of practical importance in calculating the radiative heat transfer in furnaces. This paper present that flame smissivity can be measured by the RGB function of a color camera. Three monochromatic images of red, green and blue can be acquired when flame images in furnaces are captured by color CCD cameras. Based on Wien＇s radiation law and image processing techniques, flame emissivity is detected from three monochromatic images. The detecting method is calibrated by a blackbody furnace. The experimental results in two coal-fired boilers show that flame emissivity in burner area is largest, while above the burner area flame emissivity decreases with the increase of height of furnace, the high content of ash in coal will enhance flame emissivity, and flame emissivity changed in direct proportion with the furnace load.