Line-of-Sight Temperature Profile Reconstruction of Axisymmetric Laminar Flame by Multispectral Dispersion Spectroscopy

This article introduces a novel multispectral dispersion spectroscopy method designed to reconstruct the line-of-sight (LOS) temperature profile of an axisymmetric laminar flame. By integrating multispectral thermometry with heterodyne phase-sensitive dispersion spectroscopy (HPSDS), the method enables the reconstruction of nonuniform temperature distributions along the laser path. The combination of dispersion spectral lines is optimized for measuring nonuniform temperature distribution. The simulation results validate the effectiveness of the proposed method in accurately reconstructing the LOS temperature profile. Experimental validation conducted on a laminar flat flame burner demonstrates successful reconstruction of the LOS temperature profile, with a maximum temperature deviation from thermocouple readings of within 4.5%. Furthermore, this method directly addresses the characteristic issue of nonmonotonic intensity distributions during wavelength tuning of external-cavity diode lasers (ECDLs). This article expands the application scope of laser dispersion spectroscopy (LDS) by pioneering its application in nonuniform combustion diagnostics.