Concurrent measurement of temperature and soot concentration of pulverized coal flames

This paper presents a novel instrumentation system for the concurrent measurement of temperature and soot concentration of pulverized coal flames. The system operates on the two-color principle, combining optical sensing and digital image processing techniques. The temperature and its distribution of,a flame are calculated from the ratio between the grey-levels of corresponding pixels within two images captured at two carefully selected wavelengths. The soot concentration distribution of the name is represented and estimated using the KL factor that is derived from intermediate information obtained during the temperature measurement. The system is calibrated using a tungsten lamp as a standard temperature source. The maximum relative error in the temperature measurement is 1.83%. Experimental results obtained on a 0.5-MWth combustion test facility show that the temperature distribution of a coal-fired flame ranged from 1380 to 1700 degreesC, while the KL factor ranged from 0.18 to 0.33.