Fractal Characteristics of Thin Thermal Mixing Layers in Coal-Fired Flame

The images of turbulent flame were acquired by using a digital imaging system on an industry-scale pulverized coal-fired test rig. The fractal dimensions of thin thermal mixing layers in flame were computed through morphology-based flame image processing techniques. The effects of the ratios of primary air and secondary/tertiary air on fractal dimensions were characterized. The results presented in this work show that the variations of fractal dimension are closely related to the ratio changes of primary air and secondary/tertiary air. Therefore, the fractal dimensions of flame thin thermal mixing layers can be used as an important indicator for the control and optimization of a combustion process.