Three-dimensional computerized tomographic reconstruction of instantaneous distribution of chemiluminescence of a turbulent premixed flame

The advanced CT (computerized tomography) reconstruction technique for measuring an instantaneous three-dimensional distribution of chemiluminescence of a turbulent pre-mixed flame is accomplished. In the technique, first, instantaneous two-dimensional images (`projection' images) of an objective flame are simultaneously taken from forty horizontal directions with a forty-lens camera. Next four hundred horizontal CT images, which are reconstructed from the `projection' images by MLEM (maximum likelihood expectation maximization) algorithm, are vertically accumulated, resulting in an instantaneous three-dimensional distribution of flame-chemiluminescence. Results for a propane-air fuel-rich-premixed turbulent flame are as follows. The flame front is observed to be a thin wrinkled luminous region of 0.6 mm in thickness. The three-dimensional result clearly shows that the cusps observed in horizontal cross-sections correspond to ridges of the three-dimensional flame front. The luminosity is quenched at the ridges by Lewis number effect. Finally, various types of display of three-dimensional distribution are performed to demonstrate the three-dimensionality of data acquisition.