Measurement enhancement of TDLAS based on variable weighted cross-correlation tomography for the simultaneous reconstruction of 2D temperature and concentration

Abstract

Tunable diode laser absorption tomography is a technology that enables the visualization of 2D temperature and concentration in combustion fields. This study proposes a method called variable weighted cross-correlation tomography to improve the traditional two-wavelength scheme affected by signal noise and bias error. The proposed approach combines the multiplicative algebraic reconstruction technique and pattern matching at nine wavelengths by adding peak and bottom wavelengths. In addition, this method iteratively calculates using a corrective multiplication line-of-sight and a modified return process to simultaneously estimate the images of 2D temperature and concentration. Numerical tests are performed using various thermodynamic models with additive noise. The validation experiments involving premixed methane-air flames demonstrate the good agreement between the average relative error values of the reconstructed temperature and the temperature measured using thermocouple (3.32 %), which can be ascribed to the introduction of modified broadening coefficients.