Experimental study on measurement of flame temperature distribution using the two-color method

A novel optical instrumentation system for flame characterization was developed and tested. The two-color system is capable of performing on-line measurement of flame and temperature distribution, providing temporal and spatial characterization of the combustion process. In addition, the system has the advantage of being non-intrusive. The on-line measurement of temperature distribution on a methane-air combustor revealed some interesting characteristics. When air flow rate was kept constant, an increase in CH4 flow rate would enhance the combustion intensity and elevate the flame temperature. While under constant CH4 flow rate, the increase of air flow rate would lead the measured flame temperature first to increase and then decrease. The drop of temperature might partially be caused by the heat losses due to excessive air. However, with insufficient soot particles in the flame, the temperature could be under-evaluated.