3-D flame temperature reconstruction in optical sectioning tomography

The three dimensional (3-D) flame temperature measurement is of great significance to the study of flame structure, fuel mixing and combustion mechanism, and the stability of combustion control. This paper presents the design, implementation and evaluation of a 3-D imaging system based on optical sectioning tomography to reconstruct the temperature distribution of candlelight. A 3-D luminous object can be regarded as a combination of a series of two dimensional luminous sections. Hence, based on superposition theorem, the original luminosity distribution of each section can be retrieved from focused and defocused images taken by focusing on each of sections with a single CCD camera. From the relationship between the gray level of image and the temperature, the 3-D distribution of flame temperature can be reconstructed. The experimental results on candlelight prove the feasibility of the method which can be used as a new measurement and diagnostic tool for quantitative characterization of combustion flame.