Qinfeng Liang

Multifractal detrended fluctuation analysis of combustion flames in four-burner impinging entrained-flow gasifier

Abstract On a laboratory-scale testing platform of an impinging entrained-flow gasifier with four opposed burners, the flame images for diesel combustion and gasification process were recorded with a single charge coupled device (CCD) camera. The two-dimensional multifractal detrended fluctuation analysis was employed to investigate the multifractal nature of the flame images. Sound power-law scaling relations in the annealed average of detrended fluctuations were unveiled when the order q > 0 , and the multifractal feature of flame images was confirmed. Further analyses identified two multifractal parameters, the minimum and maximum singularities α min ⁡ and α max ⁡ , serving as characteristic parameters of the multifractal flames. These two characteristic multifractal parameters vary with respect to different experimental conditions.

An Experimental Investigation on Characteristics of Individual Flame and Multi-jet Flame

In this article, the differences between individual flame and multi-jet flames are studied. The results show that the air-blast atomization flame length is co-controlled by liquid atomization and combustion intensity. Multi-jet burner is an effective method to improve combustion intensity and shorten flame absolute length. As the oxygen velocity increased, the individual flame increased in length due to better atomization, and yet the multi-jet flame length decreased owing to better combustion intensity. A further increase in oxygen velocity had little effect on flame length but flame noises and luminosity continued to increase. The temperature gradient of the multi-jet flame was higher. An empirical formula to express the variation of the multi-jet flame length and the individual flame length was given.