High-Resolution TDLAS Tomography of Gaseous Temperature and H2O Concentration in Steady Flames

In tunable diode laser absorption spectroscopy (TDLAS) tomography, high-resolution images require sufficient projections of absorbed spectral data along line-of-sight laser paths. A reflective TDLAS tomography system was designed to improve the spatial resolved ability of the images, and more than 100 projected laser paths are available in each projection coverage view. In the numerical simulations, the number of projection views and beams per view were evaluated in terms of the image errors of the flame temperature and H2O concentration. The number of projection views and beams per view are optimized for the filtered backprojection (FBP) algorithms, and the proposed reflective TDLAS tomography system yielded a spatial resolution of a grid sizing 1.625 mm. In actual experiments, reconstructed images of different flame distributions in a McKenna burner achieved a high frame rate of 20 frames/s, with a small image error for the flame imaging of temperature and H2O concentration.