Wykorzystanie cech obrazu płomienia do oceny procesu spalania

W artykule przedstawiono badania laboratoryjne, na podstawie których określono rodzaje płomieni towarzyszące różnym warunkom procesu spalania. Zmienianymi parametrami był rodzaj spalanego paliwa, wydatki pyłu węglowego oraz powietrza pierwotnego i wtórnego. W analizie uwzględniono niektóre parametry geometryczne opisujące kształt płomienia, takie jak pole obszaru płomienia, długość jego konturu i współrzędne środka ciężkości.

The paper presents flame characterisation using image processing. A laboratory combustion chamber and the methodology of investigations are described. The experiments were carried out on a laboratory stand equipped with a scaled down 1:10 swirl burner, while flows of the primary, secondary and tertiary air as well as coal were changed in order to produce different states of the combustion process. Flame images were captured by a monochrome CCD camera, mounted in an inspection opening as shown in Fig. 1a, b. During the combustion tests, four main types of flames were observed, namely: a flame corresponding to the combustion chamber warming-up phase using an auxiliary oil burner (Fig. 4a), a flame corresponding to the simultaneous operation of both main and auxiliary burner (Fig. 4b), a coal flame with instability caused by variability of the air/fuel ratio (Fig. 4c), and, finally, a flame that was typical for flame extinguishing (Fig. 4d). Since the flame was the only luminous object, determination of its area and edge was based on the pixel amplitude. Several shape parameters, such as the flame area, the flame area contour length as well as the coordinates of its gravity center were used for qualitative description of the flames under consideration. The presented analysis shows that the discussed flame shape features can be helpful for classification of various states of the combustion process and, thus, for avoiding the unstable conditions. It can result in improving the combustion efficiency and safety.