Fuel Spray Formation in an Experimental Swirl Chamber

The mixing of a fuel spray with swirling gas in a cylindrical chamber was studied by means of single shot, high speed photography. The investigation was principally concerned with the developing form of the spray, the variation of fuel concentration within it and the effect of swirl rate on this distribution. Quantitative data were obtained by scanning the photographic negatives with a densitometer; this enabled contours to be plotted to supplement the visual observations. The results indicated that the spray should be considered as consisting of several regions with differing characteristics, implying that models which fail to take account of this are unlikely to provide an accurate representation. As might be expected, the outer regions of the jet were found to be especially sensitive to changes in gas motion; the effect of swirl on the spray core was more complex than could be accounted for by assuming simple curvature of the axis.