Reconstruction of flame temperature field with optical sectioning method

The temperature information is of great significance for the study of flame structure, soot distribution and combustion mechanism. It is also vital to combustion control. This study presents the design, implementation and evaluation of a flame imaging system based on optical sectioning method to reconstruct the steady-state temperature field of candlelight. A three-dimensional luminous object can be regarded as a combination of a series of two-dimensional luminous sections; hence, based on the superposition theorem, the original luminosity distribution of each section can be retrieved from the focused and the defocused images taken by adjusting the focus plane on each of the sections with a single charge coupled device camera. From the relationship between the grey level of image and the temperature, the temperature profile of each section can be reconstructed. The experimental results prove the feasibility of the proposed method, which can be used as a new measurement and diagnostic tool for quantitative characterisation of steady-state flame.