Optical temperature measurement method of premixed flames using a multi-laser system

The temperature distribution of a methane-air premixed flame was measured by the optical measurement technique. The absorption line was decomposed through 3rd order polynomial analysis, and the simultaneous multiplicative algebraic reconstruction technique (SMART) algorithm was adopted for computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS) data reconstruction. Methane-air premixed combustion system was used to construct laminar and turbulent flames. A double tube structure was adopted to solve combustion instability factors that occur when turbulent flames are generated. To overcome the high-temperature measurement limitations of a single laser system, two types of distributed feedback (DFB) lasers were mixed and measured. The relative error in temperature was largely confirmed at the central location of the burner. It was about 1.22 % for the laminar flame and 14.47 % for the turbulent flame.