Evaluation of the possibility of using fractal analysis to study the flame in the co-firing process

The object of the study were time series reflecting changes in time of selected flame geometric parameters, in the co-firing pulverized coal and biomass. These parameters were: contour length, area size, X and Y coordinates of the geometric center of gravity. Time series were analyzed using seven popular methods for estimating the fractal dimension. The research was conducted for nine variants of the co-firing process, involving different heat power settings and the air flow rate and 30 biomass content. The results showed that the applied fractal dimensions parameters can be a feature that allows to recognize particular variants of the combustion process. Furthermore, the fractal dimension evaluated by the "madogram" method estimation gives good results for most variants providing good separability of the observations. The obtained results confirm the possibilities of using fractal analysis in flame studies in the co-firing of pulverized coal and biomass.