A comparison of multivariate LIBS and chemiluminescence-based local equivalence ratio measurements in premixed atmospheric methane-air flames

► Ungated, multivariate LIBS-based methodology for flame equivalence ratio measurements. ► Multivariate LIBS calibration better than H656nm/N500nm+ and H656nm/O777nm spectral line intensity ratio LIBS calibrations. ► Multivariate LIBS calibration provides more accurate equivalence ratio predictions compared to chemiluminescence-based calibration.