RESOLVING TURBULENT FLAME FRONT FROM MIE SCATTERING MEASUREMENTS

Turbulent swirl stabilized methane/air flames were studied to investigate the flame front characteristics. Swirl number and equivalence number were selected as 0.74 and 0.7 respectively. This study is mainly based on image processing algorithms. Therefore flame front information is recovered from Mie scattering images. Flame edges were detected by Canny edge detection algorithm. Statistical analysis was applied to instantaneous flame front areas and velocity vectors which were provided from Mie scattering images. In addition, fractal approach was employed to the flame front areas to predict the wrinkling factor thus the turbulent flame speed. As a consequence flame front was stabilized both on the edge of the inner and outer shear layer. Turbulent burning velocity was provided on the flame front by superposition of flame front found from Mie images and velocity data analyzed from Particle Image Velocimetry (PIV). Furthermore, flame area ratios were procured to reason the flame front wrinkling factor and the fractal approach to determine turbulent burning velocity. The probability density function of the turbulent flame speeds and flame area fluctuations appear to be Gaussian in shape. Measurements demonstrate that flame wrinlding increases the burning velocities by almost an order of magnitude.