Measurement of flame temperature distribution using optical tomographic and two-color pyrometric techniques

This paper presents the technique which combines optical tomographic and two-color parametric techniques for the three-dimensional (3-D) reconstruction of temperature distribution of a burner flame. Flame images are acquired using eight optical fiber bundles and two RGB CCD (charge-coupled device) cameras from eight different directions on one side of the burner. The new tomographic algorithm which combines the LFBP (Logical Filtered Back-Projection) and SART (Simultaneous Algebraic Reconstruction Technique) is proposed for the 3-D reconstruction of the gray-levels for two primary color (Red and Green) images. The temperature distribution of the flame is then determined from the ratios of the reconstructed gray-levels of the two primary color images based on the two-color principle. Experimental results on a gas fired combustion test rig are also presented and discussed. The results demonstrate that the proposed technique is effective in measuring the 3-D temperature distribution of the flame.