Temperature mapping in flames by moire deflectometry.

The theory of moire deflectometry is derived using the Fourier series approach. The advantages and disadvantages of the infinite fringe limit are demonstrated. The approach of fringe deviation is compared to the intensity measurement, which is selected as being more suitable for flames. An experimental technique based on pointwise scanning is developed to obviate the deficiencies of the video system used previously. Moire data of CH 4/air flame are interpreted, and a full map of the temperature and gas density in the flame is produced. A comparison between moire deflectometry and related techniques is given.