Research on the Flame Structure Characteristics of Methane/Air Turbulent Premixed Flame 2020-01-5075

Experiments of the methane/air turbulent premixed combustion under different turbulence intensities are conducted in a constant combustion bomb to investigate the effect of turbulence intensity on the flame structure characteristics. Fourier transform is adopted to extract detailed information of disturbance acting on the flame front of the methane/air turbulent premixed flame. The results indicate that the fluctuation radius presented an increasing trend as a whole with the development of the flame, and the flame stretch rate gradually decreases. With the increase of turbulence intensity, the disturbance of the flame front increases obviously, which makes the structure of the flame front more complex, and the correlation coefficient of the flame at the same radius decreases gradually. By analyzing the amplitude of the flame front disturbances, finding when the wave number range is 0-1, the disturbance amplitude appears the maximum value, and with the increase of turbulence intensity, the disturbance amplitude presents an increasing trend. To further explore the distribution of disturbances with wave number ranging from 5 to 280, statistical studies have been conducted of the flame front, demonstrating the distribution of the amplitude of the disturbances mainly present two peaks. With the increase of turbulence intensity, the range of the disturbances distribution gradually decreases, and as the distribution became more concentrated, the proportion of larger amplitude disturbance increases gradually.