Detection of CO concentration in a methane-air flame by TP-LIF

The principle and the linear model of two photo laser induced flluorescence(TP-LIF) were presented and discussed in this paper. The CO Q-branch (0,0) band of the B1∑+←←X1∑＋ transition was excited near 230 nm and the B1∑+→A1Π band fluorescence was detected at around 483nm. Through the analysis of the fluorescence spectrum and intensity, the effects of laser intensity, laser wavelength and the temperature on measurement were discussed. Finally the CO distribution was measured in a methane-air flame, which shows a good agreement with the results measured by other method. It was demonstrated that in the linear model of TP-LIF, the quenching effects and the other effects can be avoided. TP-LIF can be used to detect the minor species concentration conveniently.